From 0d5b05c704d1e15de2ce075f70d0de9f29ba1386 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Wed, 18 Nov 2020 20:26:58 -0500
Subject: lib: Add kconfiglib code

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 lib/kconfiglib/menuconfig.py | 3278 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 3278 insertions(+)
 create mode 100755 lib/kconfiglib/menuconfig.py

(limited to 'lib/kconfiglib/menuconfig.py')

diff --git a/lib/kconfiglib/menuconfig.py b/lib/kconfiglib/menuconfig.py
new file mode 100755
index 00000000..7e765d36
--- /dev/null
+++ b/lib/kconfiglib/menuconfig.py
@@ -0,0 +1,3278 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2018-2019, Nordic Semiconductor ASA and Ulf Magnusson
+# SPDX-License-Identifier: ISC
+
+"""
+Overview
+========
+
+A curses-based Python 2/3 menuconfig implementation. The interface should feel
+familiar to people used to mconf ('make menuconfig').
+
+Supports the same keys as mconf, and also supports a set of keybindings
+inspired by Vi:
+
+  J/K     : Down/Up
+  L       : Enter menu/Toggle item
+  H       : Leave menu
+  Ctrl-D/U: Page Down/Page Up
+  G/End   : Jump to end of list
+  g/Home  : Jump to beginning of list
+
+[Space] toggles values if possible, and enters menus otherwise. [Enter] works
+the other way around.
+
+The mconf feature where pressing a key jumps to a menu entry with that
+character in it in the current menu isn't supported. A jump-to feature for
+jumping directly to any symbol (including invisible symbols), choice, menu or
+comment (as in a Kconfig 'comment "Foo"') is available instead.
+
+A few different modes are available:
+
+  F: Toggle show-help mode, which shows the help text of the currently selected
+  item in the window at the bottom of the menu display. This is handy when
+  browsing through options.
+
+  C: Toggle show-name mode, which shows the symbol name before each symbol menu
+  entry
+
+  A: Toggle show-all mode, which shows all items, including currently invisible
+  items and items that lack a prompt. Invisible items are drawn in a different
+  style to make them stand out.
+
+
+Running
+=======
+
+menuconfig.py can be run either as a standalone executable or by calling the
+menuconfig() function with an existing Kconfig instance. The second option is a
+bit inflexible in that it will still load and save .config, etc.
+
+When run in standalone mode, the top-level Kconfig file to load can be passed
+as a command-line argument. With no argument, it defaults to "Kconfig".
+
+The KCONFIG_CONFIG environment variable specifies the .config file to load (if
+it exists) and save. If KCONFIG_CONFIG is unset, ".config" is used.
+
+When overwriting a configuration file, the old version is saved to
+<filename>.old (e.g. .config.old).
+
+$srctree is supported through Kconfiglib.
+
+
+Color schemes
+=============
+
+It is possible to customize the color scheme by setting the MENUCONFIG_STYLE
+environment variable. For example, setting it to 'aquatic' will enable an
+alternative, less yellow, more 'make menuconfig'-like color scheme, contributed
+by Mitja Horvat (pinkfluid).
+
+This is the current list of built-in styles:
+    - default       classic Kconfiglib theme with a yellow accent
+    - monochrome    colorless theme (uses only bold and standout) attributes,
+                    this style is used if the terminal doesn't support colors
+    - aquatic       blue-tinted style loosely resembling the lxdialog theme
+
+It is possible to customize the current style by changing colors of UI
+elements on the screen. This is the list of elements that can be stylized:
+
+    - path          Top row in the main display, with the menu path
+    - separator     Separator lines between windows. Also used for the top line
+                    in the symbol information display.
+    - list          List of items, e.g. the main display
+    - selection     Style for the selected item
+    - inv-list      Like list, but for invisible items. Used in show-all mode.
+    - inv-selection Like selection, but for invisible items. Used in show-all
+                    mode.
+    - help          Help text windows at the bottom of various fullscreen
+                    dialogs
+    - show-help     Window showing the help text in show-help mode
+    - frame         Frame around dialog boxes
+    - body          Body of dialog boxes
+    - edit          Edit box in pop-up dialogs
+    - jump-edit     Edit box in jump-to dialog
+    - text          Symbol information text
+
+The color definition is a comma separated list of attributes:
+
+    - fg:COLOR      Set the foreground/background colors. COLOR can be one of
+      * or *        the basic 16 colors (black, red, green, yellow, blue,
+    - bg:COLOR      magenta, cyan, white and brighter versions, for example,
+                    brightred). On terminals that support more than 8 colors,
+                    you can also directly put in a color number, e.g. fg:123
+                    (hexadecimal and octal constants are accepted as well).
+                    Colors outside the range -1..curses.COLORS-1 (which is
+                    terminal-dependent) are ignored (with a warning). The COLOR
+                    can be also specified using a RGB value in the HTML
+                    notation, for example #RRGGBB. If the terminal supports
+                    color changing, the color is rendered accurately.
+                    Otherwise, the visually nearest color is used.
+
+                    If the background or foreground color of an element is not
+                    specified, it defaults to -1, representing the default
+                    terminal foreground or background color.
+
+                    Note: On some terminals a bright version of the color
+                    implies bold.
+    - bold          Use bold text
+    - underline     Use underline text
+    - standout      Standout text attribute (reverse color)
+
+More often than not, some UI elements share the same color definition. In such
+cases the right value may specify an UI element from which the color definition
+will be copied. For example, "separator=help" will apply the current color
+definition for "help" to "separator".
+
+A keyword without the '=' is assumed to be a style template. The template name
+is looked up in the built-in styles list and the style definition is expanded
+in-place. With this, built-in styles can be used as basis for new styles.
+
+For example, take the aquatic theme and give it a red selection bar:
+
+MENUCONFIG_STYLE="aquatic selection=fg:white,bg:red"
+
+If there's an error in the style definition or if a missing style is assigned
+to, the assignment will be ignored, along with a warning being printed on
+stderr.
+
+The 'default' theme is always implicitly parsed first, so the following two
+settings have the same effect:
+
+    MENUCONFIG_STYLE="selection=fg:white,bg:red"
+    MENUCONFIG_STYLE="default selection=fg:white,bg:red"
+
+If the terminal doesn't support colors, the 'monochrome' theme is used, and
+MENUCONFIG_STYLE is ignored. The assumption is that the environment is broken
+somehow, and that the important thing is to get something usable.
+
+
+Other features
+==============
+
+  - Seamless terminal resizing
+
+  - No dependencies on *nix, as the 'curses' module is in the Python standard
+    library
+
+  - Unicode text entry
+
+  - Improved information screen compared to mconf:
+
+      * Expressions are split up by their top-level &&/|| operands to improve
+        readability
+
+      * Undefined symbols in expressions are pointed out
+
+      * Menus and comments have information displays
+
+      * Kconfig definitions are printed
+
+      * The include path is shown, listing the locations of the 'source'
+        statements that included the Kconfig file of the symbol (or other
+        item)
+
+
+Limitations
+===========
+
+Doesn't work out of the box on Windows, but can be made to work with
+
+    pip install windows-curses
+
+See the https://github.com/zephyrproject-rtos/windows-curses repository.
+"""
+from __future__ import print_function
+
+import os
+import sys
+
+_IS_WINDOWS = os.name == "nt"  # Are we running on Windows?
+
+try:
+    import curses
+except ImportError as e:
+    if not _IS_WINDOWS:
+        raise
+    sys.exit("""\
+menuconfig failed to import the standard Python 'curses' library. Try
+installing a package like windows-curses
+(https://github.com/zephyrproject-rtos/windows-curses) by running this command
+in cmd.exe:
+
+    pip install windows-curses
+
+Starting with Kconfiglib 13.0.0, windows-curses is no longer automatically
+installed when installing Kconfiglib via pip on Windows (because it breaks
+installation on MSYS2).
+
+Exception:
+{}: {}""".format(type(e).__name__, e))
+
+import errno
+import locale
+import re
+import textwrap
+
+from kconfiglib import Symbol, Choice, MENU, COMMENT, MenuNode, \
+                       BOOL, TRISTATE, STRING, INT, HEX, \
+                       AND, OR, \
+                       expr_str, expr_value, split_expr, \
+                       standard_sc_expr_str, \
+                       TRI_TO_STR, TYPE_TO_STR, \
+                       standard_kconfig, standard_config_filename
+
+
+#
+# Configuration variables
+#
+
+# If True, try to change LC_CTYPE to a UTF-8 locale if it is set to the C
+# locale (which implies ASCII). This fixes curses Unicode I/O issues on systems
+# with bad defaults. ncurses configures itself from the locale settings.
+#
+# Related PEP: https://www.python.org/dev/peps/pep-0538/
+_CHANGE_C_LC_CTYPE_TO_UTF8 = True
+
+# How many steps an implicit submenu will be indented. Implicit submenus are
+# created when an item depends on the symbol before it. Note that symbols
+# defined with 'menuconfig' create a separate menu instead of indenting.
+_SUBMENU_INDENT = 4
+
+# Number of steps for Page Up/Down to jump
+_PG_JUMP = 6
+
+# Height of the help window in show-help mode
+_SHOW_HELP_HEIGHT = 8
+
+# How far the cursor needs to be from the edge of the window before it starts
+# to scroll. Used for the main menu display, the information display, the
+# search display, and for text boxes.
+_SCROLL_OFFSET = 5
+
+# Minimum width of dialogs that ask for text input
+_INPUT_DIALOG_MIN_WIDTH = 30
+
+# Number of arrows pointing up/down to draw when a window is scrolled
+_N_SCROLL_ARROWS = 14
+
+# Lines of help text shown at the bottom of the "main" display
+_MAIN_HELP_LINES = """
+[Space/Enter] Toggle/enter  [ESC] Leave menu           [S] Save
+[O] Load                    [?] Symbol info            [/] Jump to symbol
+[F] Toggle show-help mode   [C] Toggle show-name mode  [A] Toggle show-all mode
+[Q] Quit (prompts for save) [D] Save minimal config (advanced)
+"""[1:-1].split("\n")
+
+# Lines of help text shown at the bottom of the information dialog
+_INFO_HELP_LINES = """
+[ESC/q] Return to menu      [/] Jump to symbol
+"""[1:-1].split("\n")
+
+# Lines of help text shown at the bottom of the search dialog
+_JUMP_TO_HELP_LINES = """
+Type text to narrow the search. Regexes are supported (via Python's 're'
+module). The up/down cursor keys step in the list. [Enter] jumps to the
+selected symbol. [ESC] aborts the search. Type multiple space-separated
+strings/regexes to find entries that match all of them. Type Ctrl-F to
+view the help of the selected item without leaving the dialog.
+"""[1:-1].split("\n")
+
+#
+# Styling
+#
+
+_STYLES = {
+    "default": """
+    path=fg:black,bg:white,bold
+    separator=fg:black,bg:yellow,bold
+    list=fg:black,bg:white
+    selection=fg:white,bg:blue,bold
+    inv-list=fg:red,bg:white
+    inv-selection=fg:red,bg:blue
+    help=path
+    show-help=list
+    frame=fg:black,bg:yellow,bold
+    body=fg:white,bg:black
+    edit=fg:white,bg:blue
+    jump-edit=edit
+    text=list
+    """,
+
+    # This style is forced on terminals that do no support colors
+    "monochrome": """
+    path=bold
+    separator=bold,standout
+    list=
+    selection=bold,standout
+    inv-list=bold
+    inv-selection=bold,standout
+    help=bold
+    show-help=
+    frame=bold,standout
+    body=
+    edit=standout
+    jump-edit=
+    text=
+    """,
+
+    # Blue-tinted style loosely resembling lxdialog
+    "aquatic": """
+    path=fg:white,bg:blue
+    separator=fg:white,bg:cyan
+    help=path
+    frame=fg:white,bg:cyan
+    body=fg:white,bg:blue
+    edit=fg:black,bg:white
+    """
+}
+
+_NAMED_COLORS = {
+    # Basic colors
+    "black":         curses.COLOR_BLACK,
+    "red":           curses.COLOR_RED,
+    "green":         curses.COLOR_GREEN,
+    "yellow":        curses.COLOR_YELLOW,
+    "blue":          curses.COLOR_BLUE,
+    "magenta":       curses.COLOR_MAGENTA,
+    "cyan":          curses.COLOR_CYAN,
+    "white":         curses.COLOR_WHITE,
+
+    # Bright versions
+    "brightblack":   curses.COLOR_BLACK + 8,
+    "brightred":     curses.COLOR_RED + 8,
+    "brightgreen":   curses.COLOR_GREEN + 8,
+    "brightyellow":  curses.COLOR_YELLOW + 8,
+    "brightblue":    curses.COLOR_BLUE + 8,
+    "brightmagenta": curses.COLOR_MAGENTA + 8,
+    "brightcyan":    curses.COLOR_CYAN + 8,
+    "brightwhite":   curses.COLOR_WHITE + 8,
+
+    # Aliases
+    "purple":        curses.COLOR_MAGENTA,
+    "brightpurple":  curses.COLOR_MAGENTA + 8,
+}
+
+
+def _rgb_to_6cube(rgb):
+    # Converts an 888 RGB color to a 3-tuple (nice in that it's hashable)
+    # representing the closest xterm 256-color 6x6x6 color cube color.
+    #
+    # The xterm 256-color extension uses a RGB color palette with components in
+    # the range 0-5 (a 6x6x6 cube). The catch is that the mapping is nonlinear.
+    # Index 0 in the 6x6x6 cube is mapped to 0, index 1 to 95, then 135, 175,
+    # etc., in increments of 40. See the links below:
+    #
+    #   https://commons.wikimedia.org/wiki/File:Xterm_256color_chart.svg
+    #   https://github.com/tmux/tmux/blob/master/colour.c
+
+    # 48 is the middle ground between 0 and 95.
+    return tuple(0 if x < 48 else int(round(max(1, (x - 55)/40))) for x in rgb)
+
+
+def _6cube_to_rgb(r6g6b6):
+    # Returns the 888 RGB color for a 666 xterm color cube index
+
+    return tuple(0 if x == 0 else 40*x + 55 for x in r6g6b6)
+
+
+def _rgb_to_gray(rgb):
+    # Converts an 888 RGB color to the index of an xterm 256-color grayscale
+    # color with approx. the same perceived brightness
+
+    # Calculate the luminance (gray intensity) of the color. See
+    #   https://stackoverflow.com/questions/596216/formula-to-determine-brightness-of-rgb-color
+    # and
+    #   https://www.w3.org/TR/AERT/#color-contrast
+    luma = 0.299*rgb[0] + 0.587*rgb[1] + 0.114*rgb[2]
+
+    # Closest index in the grayscale palette, which starts at RGB 0x080808,
+    # with stepping 0x0A0A0A
+    index = int(round((luma - 8)/10))
+
+    # Clamp the index to 0-23, corresponding to 232-255
+    return max(0, min(index, 23))
+
+
+def _gray_to_rgb(index):
+    # Convert a grayscale index to its closet single RGB component
+
+    return 3*(10*index + 8,)  # Returns a 3-tuple
+
+
+# Obscure Python: We never pass a value for rgb2index, and it keeps pointing to
+# the same dict. This avoids a global.
+def _alloc_rgb(rgb, rgb2index={}):
+    # Initialize a new entry in the xterm palette to the given RGB color,
+    # returning its index. If the color has already been initialized, the index
+    # of the existing entry is returned.
+    #
+    # ncurses is palette-based, so we need to overwrite palette entries to make
+    # new colors.
+    #
+    # The colors from 0 to 15 are user-defined, and there's no way to query
+    # their RGB values, so we better leave them untouched. Also leave any
+    # hypothetical colors above 255 untouched (though we're unlikely to
+    # allocate that many colors anyway).
+
+    if rgb in rgb2index:
+        return rgb2index[rgb]
+
+    # Many terminals allow the user to customize the first 16 colors. Avoid
+    # changing their values.
+    color_index = 16 + len(rgb2index)
+    if color_index >= 256:
+        _warn("Unable to allocate new RGB color ", rgb, ". Too many colors "
+              "allocated.")
+        return 0
+
+    # Map each RGB component from the range 0-255 to the range 0-1000, which is
+    # what curses uses
+    curses.init_color(color_index, *(int(round(1000*x/255)) for x in rgb))
+    rgb2index[rgb] = color_index
+
+    return color_index
+
+
+def _color_from_num(num):
+    # Returns the index of a color that looks like color 'num' in the xterm
+    # 256-color palette (but that might not be 'num', if we're redefining
+    # colors)
+
+    # - _alloc_rgb() won't touch the first 16 colors or any (hypothetical)
+    #   colors above 255, so we can always return them as-is
+    #
+    # - If the terminal doesn't support changing color definitions, or if
+    #   curses.COLORS < 256, _alloc_rgb() won't touch any color, and all colors
+    #   can be returned as-is
+    if num < 16 or num > 255 or not curses.can_change_color() or \
+       curses.COLORS < 256:
+        return num
+
+    # _alloc_rgb() might redefine colors, so emulate the xterm 256-color
+    # palette by allocating new colors instead of returning color numbers
+    # directly
+
+    if num < 232:
+        num -= 16
+        return _alloc_rgb(_6cube_to_rgb(((num//36)%6, (num//6)%6, num%6)))
+
+    return _alloc_rgb(_gray_to_rgb(num - 232))
+
+
+def _color_from_rgb(rgb):
+    # Returns the index of a color matching the 888 RGB color 'rgb'. The
+    # returned color might be an ~exact match or an approximation, depending on
+    # terminal capabilities.
+
+    # Calculates the Euclidean distance between two RGB colors
+    def dist(r1, r2): return sum((x - y)**2 for x, y in zip(r1, r2))
+
+    if curses.COLORS >= 256:
+        # Assume we're dealing with xterm's 256-color extension
+
+        if curses.can_change_color():
+            # Best case -- the terminal supports changing palette entries via
+            # curses.init_color(). Initialize an unused palette entry and
+            # return it.
+            return _alloc_rgb(rgb)
+
+        # Second best case -- pick between the xterm 256-color extension colors
+
+        # Closest 6-cube "color" color
+        c6 = _rgb_to_6cube(rgb)
+        # Closest gray color
+        gray = _rgb_to_gray(rgb)
+
+        if dist(rgb, _6cube_to_rgb(c6)) < dist(rgb, _gray_to_rgb(gray)):
+            # Use the "color" color from the 6x6x6 color palette. Calculate the
+            # color number from the 6-cube index triplet.
+            return 16 + 36*c6[0] + 6*c6[1] + c6[2]
+
+        # Use the color from the gray palette
+        return 232 + gray
+
+    # Terminal not in xterm 256-color mode. This is probably the best we can
+    # do, or is it? Submit patches. :)
+    min_dist = float('inf')
+    best = -1
+    for color in range(curses.COLORS):
+        # ncurses uses the range 0..1000. Scale that down to 0..255.
+        d = dist(rgb, tuple(int(round(255*c/1000))
+                            for c in curses.color_content(color)))
+        if d < min_dist:
+            min_dist = d
+            best = color
+
+    return best
+
+
+def _parse_style(style_str, parsing_default):
+    # Parses a string with '<element>=<style>' assignments. Anything not
+    # containing '=' is assumed to be a reference to a built-in style, which is
+    # treated as if all the assignments from the style were inserted at that
+    # point in the string.
+    #
+    # The parsing_default flag is set to True when we're implicitly parsing the
+    # 'default'/'monochrome' style, to prevent warnings.
+
+    for sline in style_str.split():
+        # Words without a "=" character represents a style template
+        if "=" in sline:
+            key, data = sline.split("=", 1)
+
+            # The 'default' style template is assumed to define all keys. We
+            # run _style_to_curses() for non-existing keys as well, so that we
+            # print warnings for errors to the right of '=' for those too.
+            if key not in _style and not parsing_default:
+                _warn("Ignoring non-existent style", key)
+
+            # If data is a reference to another key, copy its style
+            if data in _style:
+                _style[key] = _style[data]
+            else:
+                _style[key] = _style_to_curses(data)
+
+        elif sline in _STYLES:
+            # Recursively parse style template. Ignore styles that don't exist,
+            # for backwards/forwards compatibility.
+            _parse_style(_STYLES[sline], parsing_default)
+
+        else:
+            _warn("Ignoring non-existent style template", sline)
+
+# Dictionary mapping element types to the curses attributes used to display
+# them
+_style = {}
+
+
+def _style_to_curses(style_def):
+    # Parses a style definition string (<element>=<style>), returning
+    # a (fg_color, bg_color, attributes) tuple.
+
+    def parse_color(color_def):
+        color_def = color_def.split(":", 1)[1]
+
+        # HTML format, #RRGGBB
+        if re.match("#[A-Fa-f0-9]{6}", color_def):
+            return _color_from_rgb((
+                int(color_def[1:3], 16),
+                int(color_def[3:5], 16),
+                int(color_def[5:7], 16)))
+
+        if color_def in _NAMED_COLORS:
+            color_num = _color_from_num(_NAMED_COLORS[color_def])
+        else:
+            try:
+                color_num = _color_from_num(int(color_def, 0))
+            except ValueError:
+                _warn("Ignoring color", color_def, "that's neither "
+                      "predefined nor a number")
+                return -1
+
+        if not -1 <= color_num < curses.COLORS:
+            _warn("Ignoring color {}, which is outside the range "
+                  "-1..curses.COLORS-1 (-1..{})"
+                  .format(color_def, curses.COLORS - 1))
+            return -1
+
+        return color_num
+
+    fg_color = -1
+    bg_color = -1
+    attrs = 0
+
+    if style_def:
+        for field in style_def.split(","):
+            if field.startswith("fg:"):
+                fg_color = parse_color(field)
+            elif field.startswith("bg:"):
+                bg_color = parse_color(field)
+            elif field == "bold":
+                # A_BOLD tends to produce faint and hard-to-read text on the
+                # Windows console, especially with the old color scheme, before
+                # the introduction of
+                # https://blogs.msdn.microsoft.com/commandline/2017/08/02/updating-the-windows-console-colors/
+                attrs |= curses.A_NORMAL if _IS_WINDOWS else curses.A_BOLD
+            elif field == "standout":
+                attrs |= curses.A_STANDOUT
+            elif field == "underline":
+                attrs |= curses.A_UNDERLINE
+            else:
+                _warn("Ignoring unknown style attribute", field)
+
+    return _style_attr(fg_color, bg_color, attrs)
+
+
+def _init_styles():
+    if curses.has_colors():
+        try:
+            curses.use_default_colors()
+        except curses.error:
+            # Ignore errors on funky terminals that support colors but not
+            # using default colors. Worst it can do is break transparency and
+            # the like. Ran across this with the MSYS2/winpty setup in
+            # https://github.com/msys2/MINGW-packages/issues/5823, though there
+            # seems to be a lot of general brokenness there.
+            pass
+
+        # Use the 'default' theme as the base, and add any user-defined style
+        # settings from the environment
+        _parse_style("default", True)
+        if "MENUCONFIG_STYLE" in os.environ:
+            _parse_style(os.environ["MENUCONFIG_STYLE"], False)
+    else:
+        # Force the 'monochrome' theme if the terminal doesn't support colors.
+        # MENUCONFIG_STYLE is likely to mess things up here (though any colors
+        # would be ignored), so ignore it.
+        _parse_style("monochrome", True)
+
+
+# color_attribs holds the color pairs we've already created, indexed by a
+# (<foreground color>, <background color>) tuple.
+#
+# Obscure Python: We never pass a value for color_attribs, and it keeps
+# pointing to the same dict. This avoids a global.
+def _style_attr(fg_color, bg_color, attribs, color_attribs={}):
+    # Returns an attribute with the specified foreground and background color
+    # and the attributes in 'attribs'. Reuses color pairs already created if
+    # possible, and creates a new color pair otherwise.
+    #
+    # Returns 'attribs' if colors aren't supported.
+
+    if not curses.has_colors():
+        return attribs
+
+    if (fg_color, bg_color) not in color_attribs:
+        # Create new color pair. Color pair number 0 is hardcoded and cannot be
+        # changed, hence the +1s.
+        curses.init_pair(len(color_attribs) + 1, fg_color, bg_color)
+        color_attribs[(fg_color, bg_color)] = \
+            curses.color_pair(len(color_attribs) + 1)
+
+    return color_attribs[(fg_color, bg_color)] | attribs
+
+
+#
+# Main application
+#
+
+
+def _main():
+    menuconfig(standard_kconfig(__doc__))
+
+
+def menuconfig(kconf):
+    """
+    Launches the configuration interface, returning after the user exits.
+
+    kconf:
+      Kconfig instance to be configured
+    """
+    global _kconf
+    global _conf_filename
+    global _conf_changed
+    global _minconf_filename
+    global _show_all
+
+    _kconf = kconf
+
+    # Filename to save configuration to
+    _conf_filename = standard_config_filename()
+
+    # Load existing configuration and set _conf_changed True if it is outdated
+    _conf_changed = _load_config()
+
+    # Filename to save minimal configuration to
+    _minconf_filename = "defconfig"
+
+    # Any visible items in the top menu?
+    _show_all = False
+    if not _shown_nodes(kconf.top_node):
+        # Nothing visible. Start in show-all mode and try again.
+        _show_all = True
+        if not _shown_nodes(kconf.top_node):
+            # Give up. The implementation relies on always having a selected
+            # node.
+            print("Empty configuration -- nothing to configure.\n"
+                  "Check that environment variables are set properly.")
+            return
+
+    # Disable warnings. They get mangled in curses mode, and we deal with
+    # errors ourselves.
+    kconf.warn = False
+
+    # Make curses use the locale settings specified in the environment
+    locale.setlocale(locale.LC_ALL, "")
+
+    # Try to fix Unicode issues on systems with bad defaults
+    if _CHANGE_C_LC_CTYPE_TO_UTF8:
+        _change_c_lc_ctype_to_utf8()
+
+    # Get rid of the delay between pressing ESC and jumping to the parent menu,
+    # unless the user has set ESCDELAY (see ncurses(3)). This makes the UI much
+    # smoother to work with.
+    #
+    # Note: This is strictly pretty iffy, since escape codes for e.g. cursor
+    # keys start with ESC, but I've never seen it cause problems in practice
+    # (probably because it's unlikely that the escape code for a key would get
+    # split up across read()s, at least with a terminal emulator). Please
+    # report if you run into issues. Some suitable small default value could be
+    # used here instead in that case. Maybe it's silly to not put in the
+    # smallest imperceptible delay here already, though I don't like guessing.
+    #
+    # (From a quick glance at the ncurses source code, ESCDELAY might only be
+    # relevant for mouse events there, so maybe escapes are assumed to arrive
+    # in one piece already...)
+    os.environ.setdefault("ESCDELAY", "0")
+
+    # Enter curses mode. _menuconfig() returns a string to print on exit, after
+    # curses has been de-initialized.
+    print(curses.wrapper(_menuconfig))
+
+
+def _load_config():
+    # Loads any existing .config file. See the Kconfig.load_config() docstring.
+    #
+    # Returns True if .config is missing or outdated. We always prompt for
+    # saving the configuration in that case.
+
+    print(_kconf.load_config())
+    if not os.path.exists(_conf_filename):
+        # No .config
+        return True
+
+    return _needs_save()
+
+
+def _needs_save():
+    # Returns True if a just-loaded .config file is outdated (would get
+    # modified when saving)
+
+    if _kconf.missing_syms:
+        # Assignments to undefined symbols in the .config
+        return True
+
+    for sym in _kconf.unique_defined_syms:
+        if sym.user_value is None:
+            if sym.config_string:
+                # Unwritten symbol
+                return True
+        elif sym.orig_type in (BOOL, TRISTATE):
+            if sym.tri_value != sym.user_value:
+                # Written bool/tristate symbol, new value
+                return True
+        elif sym.str_value != sym.user_value:
+            # Written string/int/hex symbol, new value
+            return True
+
+    # No need to prompt for save
+    return False
+
+
+# Global variables used below:
+#
+#   _stdscr:
+#     stdscr from curses
+#
+#   _cur_menu:
+#     Menu node of the menu (or menuconfig symbol, or choice) currently being
+#     shown
+#
+#   _shown:
+#     List of items in _cur_menu that are shown (ignoring scrolling). In
+#     show-all mode, this list contains all items in _cur_menu. Otherwise, it
+#     contains just the visible items.
+#
+#   _sel_node_i:
+#     Index in _shown of the currently selected node
+#
+#   _menu_scroll:
+#     Index in _shown of the top row of the main display
+#
+#   _parent_screen_rows:
+#     List/stack of the row numbers that the selections in the parent menus
+#     appeared on. This is used to prevent the scrolling from jumping around
+#     when going in and out of menus.
+#
+#   _show_help/_show_name/_show_all:
+#     If True, the corresponding mode is on. See the module docstring.
+#
+#   _conf_filename:
+#     File to save the configuration to
+#
+#   _minconf_filename:
+#     File to save minimal configurations to
+#
+#   _conf_changed:
+#     True if the configuration has been changed. If False, we don't bother
+#     showing the save-and-quit dialog.
+#
+#     We reset this to False whenever the configuration is saved explicitly
+#     from the save dialog.
+
+
+def _menuconfig(stdscr):
+    # Logic for the main display, with the list of symbols, etc.
+
+    global _stdscr
+    global _conf_filename
+    global _conf_changed
+    global _minconf_filename
+    global _show_help
+    global _show_name
+
+    _stdscr = stdscr
+
+    _init()
+
+    while True:
+        _draw_main()
+        curses.doupdate()
+
+
+        c = _getch_compat(_menu_win)
+
+        if c == curses.KEY_RESIZE:
+            _resize_main()
+
+        elif c in (curses.KEY_DOWN, "j", "J"):
+            _select_next_menu_entry()
+
+        elif c in (curses.KEY_UP, "k", "K"):
+            _select_prev_menu_entry()
+
+        elif c in (curses.KEY_NPAGE, "\x04"):  # Page Down/Ctrl-D
+            # Keep it simple. This way we get sane behavior for small windows,
+            # etc., for free.
+            for _ in range(_PG_JUMP):
+                _select_next_menu_entry()
+
+        elif c in (curses.KEY_PPAGE, "\x15"):  # Page Up/Ctrl-U
+            for _ in range(_PG_JUMP):
+                _select_prev_menu_entry()
+
+        elif c in (curses.KEY_END, "G"):
+            _select_last_menu_entry()
+
+        elif c in (curses.KEY_HOME, "g"):
+            _select_first_menu_entry()
+
+        elif c == " ":
+            # Toggle the node if possible
+            sel_node = _shown[_sel_node_i]
+            if not _change_node(sel_node):
+                _enter_menu(sel_node)
+
+        elif c in (curses.KEY_RIGHT, "\n", "l", "L"):
+            # Enter the node if possible
+            sel_node = _shown[_sel_node_i]
+            if not _enter_menu(sel_node):
+                _change_node(sel_node)
+
+        elif c in ("n", "N"):
+            _set_sel_node_tri_val(0)
+
+        elif c in ("m", "M"):
+            _set_sel_node_tri_val(1)
+
+        elif c in ("y", "Y"):
+            _set_sel_node_tri_val(2)
+
+        elif c in (curses.KEY_LEFT, curses.KEY_BACKSPACE, _ERASE_CHAR,
+                   "\x1B", "h", "H"):  # \x1B = ESC
+
+            if c == "\x1B" and _cur_menu is _kconf.top_node:
+                res = _quit_dialog()
+                if res:
+                    return res
+            else:
+                _leave_menu()
+
+        elif c in ("o", "O"):
+            _load_dialog()
+
+        elif c in ("s", "S"):
+            filename = _save_dialog(_kconf.write_config, _conf_filename,
+                                    "configuration")
+            if filename:
+                _conf_filename = filename
+                _conf_changed = False
+
+        elif c in ("d", "D"):
+            filename = _save_dialog(_kconf.write_min_config, _minconf_filename,
+                                    "minimal configuration")
+            if filename:
+                _minconf_filename = filename
+
+        elif c == "/":
+            _jump_to_dialog()
+            # The terminal might have been resized while the fullscreen jump-to
+            # dialog was open
+            _resize_main()
+
+        elif c == "?":
+            _info_dialog(_shown[_sel_node_i], False)
+            # The terminal might have been resized while the fullscreen info
+            # dialog was open
+            _resize_main()
+
+        elif c in ("f", "F"):
+            _show_help = not _show_help
+            _set_style(_help_win, "show-help" if _show_help else "help")
+            _resize_main()
+
+        elif c in ("c", "C"):
+            _show_name = not _show_name
+
+        elif c in ("a", "A"):
+            _toggle_show_all()
+
+        elif c in ("q", "Q"):
+            res = _quit_dialog()
+            if res:
+                return res
+
+
+def _quit_dialog():
+    if not _conf_changed:
+        return "No changes to save (for '{}')".format(_conf_filename)
+
+    while True:
+        c = _key_dialog(
+            "Quit",
+            " Save configuration?\n"
+            "\n"
+            "(Y)es  (N)o  (C)ancel",
+            "ync")
+
+        if c is None or c == "c":
+            return None
+
+        if c == "y":
+            # Returns a message to print
+            msg = _try_save(_kconf.write_config, _conf_filename, "configuration")
+            if msg:
+                return msg
+
+        elif c == "n":
+            return "Configuration ({}) was not saved".format(_conf_filename)
+
+
+def _init():
+    # Initializes the main display with the list of symbols, etc. Also does
+    # misc. global initialization that needs to happen after initializing
+    # curses.
+
+    global _ERASE_CHAR
+
+    global _path_win
+    global _top_sep_win
+    global _menu_win
+    global _bot_sep_win
+    global _help_win
+
+    global _parent_screen_rows
+    global _cur_menu
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+
+    global _show_help
+    global _show_name
+
+    # Looking for this in addition to KEY_BACKSPACE (which is unreliable) makes
+    # backspace work with TERM=vt100. That makes it likely to work in sane
+    # environments.
+    _ERASE_CHAR = curses.erasechar()
+    if sys.version_info[0] >= 3:
+        # erasechar() returns a one-byte bytes object on Python 3. This sets
+        # _ERASE_CHAR to a blank string if it can't be decoded, which should be
+        # harmless.
+        _ERASE_CHAR = _ERASE_CHAR.decode("utf-8", "ignore")
+
+    _init_styles()
+
+    # Hide the cursor
+    _safe_curs_set(0)
+
+    # Initialize windows
+
+    # Top row, with menu path
+    _path_win = _styled_win("path")
+
+    # Separator below menu path, with title and arrows pointing up
+    _top_sep_win = _styled_win("separator")
+
+    # List of menu entries with symbols, etc.
+    _menu_win = _styled_win("list")
+    _menu_win.keypad(True)
+
+    # Row below menu list, with arrows pointing down
+    _bot_sep_win = _styled_win("separator")
+
+    # Help window with keys at the bottom. Shows help texts in show-help mode.
+    _help_win = _styled_win("help")
+
+    # The rows we'd like the nodes in the parent menus to appear on. This
+    # prevents the scroll from jumping around when going in and out of menus.
+    _parent_screen_rows = []
+
+    # Initial state
+
+    _cur_menu = _kconf.top_node
+    _shown = _shown_nodes(_cur_menu)
+    _sel_node_i = _menu_scroll = 0
+
+    _show_help = _show_name = False
+
+    # Give windows their initial size
+    _resize_main()
+
+
+def _resize_main():
+    # Resizes the main display, with the list of symbols, etc., to fill the
+    # terminal
+
+    global _menu_scroll
+
+    screen_height, screen_width = _stdscr.getmaxyx()
+
+    _path_win.resize(1, screen_width)
+    _top_sep_win.resize(1, screen_width)
+    _bot_sep_win.resize(1, screen_width)
+
+    help_win_height = _SHOW_HELP_HEIGHT if _show_help else \
+        len(_MAIN_HELP_LINES)
+
+    menu_win_height = screen_height - help_win_height - 3
+
+    if menu_win_height >= 1:
+        _menu_win.resize(menu_win_height, screen_width)
+        _help_win.resize(help_win_height, screen_width)
+
+        _top_sep_win.mvwin(1, 0)
+        _menu_win.mvwin(2, 0)
+        _bot_sep_win.mvwin(2 + menu_win_height, 0)
+        _help_win.mvwin(2 + menu_win_height + 1, 0)
+    else:
+        # Degenerate case. Give up on nice rendering and just prevent errors.
+
+        menu_win_height = 1
+
+        _menu_win.resize(1, screen_width)
+        _help_win.resize(1, screen_width)
+
+        for win in _top_sep_win, _menu_win, _bot_sep_win, _help_win:
+            win.mvwin(0, 0)
+
+    # Adjust the scroll so that the selected node is still within the window,
+    # if needed
+    if _sel_node_i - _menu_scroll >= menu_win_height:
+        _menu_scroll = _sel_node_i - menu_win_height + 1
+
+
+def _height(win):
+    # Returns the height of 'win'
+
+    return win.getmaxyx()[0]
+
+
+def _width(win):
+    # Returns the width of 'win'
+
+    return win.getmaxyx()[1]
+
+
+def _enter_menu(menu):
+    # Makes 'menu' the currently displayed menu. In addition to actual 'menu's,
+    # "menu" here includes choices and symbols defined with the 'menuconfig'
+    # keyword.
+    #
+    # Returns False if 'menu' can't be entered.
+
+    global _cur_menu
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+
+    if not menu.is_menuconfig:
+        return False  # Not a menu
+
+    shown_sub = _shown_nodes(menu)
+    # Never enter empty menus. We depend on having a current node.
+    if not shown_sub:
+        return False
+
+    # Remember where the current node appears on the screen, so we can try
+    # to get it to appear in the same place when we leave the menu
+    _parent_screen_rows.append(_sel_node_i - _menu_scroll)
+
+    # Jump into menu
+    _cur_menu = menu
+    _shown = shown_sub
+    _sel_node_i = _menu_scroll = 0
+
+    if isinstance(menu.item, Choice):
+        _select_selected_choice_sym()
+
+    return True
+
+
+def _select_selected_choice_sym():
+    # Puts the cursor on the currently selected (y-valued) choice symbol, if
+    # any. Does nothing if if the choice has no selection (is not visible/in y
+    # mode).
+
+    global _sel_node_i
+
+    choice = _cur_menu.item
+    if choice.selection:
+        # Search through all menu nodes to handle choice symbols being defined
+        # in multiple locations
+        for node in choice.selection.nodes:
+            if node in _shown:
+                _sel_node_i = _shown.index(node)
+                _center_vertically()
+                return
+
+
+def _jump_to(node):
+    # Jumps directly to the menu node 'node'
+
+    global _cur_menu
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+    global _show_all
+    global _parent_screen_rows
+
+    # Clear remembered menu locations. We might not even have been in the
+    # parent menus before.
+    _parent_screen_rows = []
+
+    old_show_all = _show_all
+    jump_into = (isinstance(node.item, Choice) or node.item == MENU) and \
+                node.list
+
+    # If we're jumping to a non-empty choice or menu, jump to the first entry
+    # in it instead of jumping to its menu node
+    if jump_into:
+        _cur_menu = node
+        node = node.list
+    else:
+        _cur_menu = _parent_menu(node)
+
+    _shown = _shown_nodes(_cur_menu)
+    if node not in _shown:
+        # The node wouldn't be shown. Turn on show-all to show it.
+        _show_all = True
+        _shown = _shown_nodes(_cur_menu)
+
+    _sel_node_i = _shown.index(node)
+
+    if jump_into and not old_show_all and _show_all:
+        # If we're jumping into a choice or menu and were forced to turn on
+        # show-all because the first entry wasn't visible, try turning it off.
+        # That will land us at the first visible node if there are visible
+        # nodes, and is a no-op otherwise.
+        _toggle_show_all()
+
+    _center_vertically()
+
+    # If we're jumping to a non-empty choice, jump to the selected symbol, if
+    # any
+    if jump_into and isinstance(_cur_menu.item, Choice):
+        _select_selected_choice_sym()
+
+
+def _leave_menu():
+    # Jumps to the parent menu of the current menu. Does nothing if we're in
+    # the top menu.
+
+    global _cur_menu
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+
+    if _cur_menu is _kconf.top_node:
+        return
+
+    # Jump to parent menu
+    parent = _parent_menu(_cur_menu)
+    _shown = _shown_nodes(parent)
+    _sel_node_i = _shown.index(_cur_menu)
+    _cur_menu = parent
+
+    # Try to make the menu entry appear on the same row on the screen as it did
+    # before we entered the menu.
+
+    if _parent_screen_rows:
+        # The terminal might have shrunk since we were last in the parent menu
+        screen_row = min(_parent_screen_rows.pop(), _height(_menu_win) - 1)
+        _menu_scroll = max(_sel_node_i - screen_row, 0)
+    else:
+        # No saved parent menu locations, meaning we jumped directly to some
+        # node earlier
+        _center_vertically()
+
+
+def _select_next_menu_entry():
+    # Selects the menu entry after the current one, adjusting the scroll if
+    # necessary. Does nothing if we're already at the last menu entry.
+
+    global _sel_node_i
+    global _menu_scroll
+
+    if _sel_node_i < len(_shown) - 1:
+        # Jump to the next node
+        _sel_node_i += 1
+
+        # If the new node is sufficiently close to the edge of the menu window
+        # (as determined by _SCROLL_OFFSET), increase the scroll by one. This
+        # gives nice and non-jumpy behavior even when
+        # _SCROLL_OFFSET >= _height(_menu_win).
+        if _sel_node_i >= _menu_scroll + _height(_menu_win) - _SCROLL_OFFSET \
+           and _menu_scroll < _max_scroll(_shown, _menu_win):
+
+            _menu_scroll += 1
+
+
+def _select_prev_menu_entry():
+    # Selects the menu entry before the current one, adjusting the scroll if
+    # necessary. Does nothing if we're already at the first menu entry.
+
+    global _sel_node_i
+    global _menu_scroll
+
+    if _sel_node_i > 0:
+        # Jump to the previous node
+        _sel_node_i -= 1
+
+        # See _select_next_menu_entry()
+        if _sel_node_i < _menu_scroll + _SCROLL_OFFSET:
+            _menu_scroll = max(_menu_scroll - 1, 0)
+
+
+def _select_last_menu_entry():
+    # Selects the last menu entry in the current menu
+
+    global _sel_node_i
+    global _menu_scroll
+
+    _sel_node_i = len(_shown) - 1
+    _menu_scroll = _max_scroll(_shown, _menu_win)
+
+
+def _select_first_menu_entry():
+    # Selects the first menu entry in the current menu
+
+    global _sel_node_i
+    global _menu_scroll
+
+    _sel_node_i = _menu_scroll = 0
+
+
+def _toggle_show_all():
+    # Toggles show-all mode on/off. If turning it off would give no visible
+    # items in the current menu, it is left on.
+
+    global _show_all
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+
+    # Row on the screen the cursor is on. Preferably we want the same row to
+    # stay highlighted.
+    old_row = _sel_node_i - _menu_scroll
+
+    _show_all = not _show_all
+    # List of new nodes to be shown after toggling _show_all
+    new_shown = _shown_nodes(_cur_menu)
+
+    # Find a good node to select. The selected node might disappear if show-all
+    # mode is turned off.
+
+    # Select the previously selected node itself if it is still visible. If
+    # there are visible nodes before it, select the closest one.
+    for node in _shown[_sel_node_i::-1]:
+        if node in new_shown:
+            _sel_node_i = new_shown.index(node)
+            break
+    else:
+        # No visible nodes before the previously selected node. Select the
+        # closest visible node after it instead.
+        for node in _shown[_sel_node_i + 1:]:
+            if node in new_shown:
+                _sel_node_i = new_shown.index(node)
+                break
+        else:
+            # No visible nodes at all, meaning show-all was turned off inside
+            # an invisible menu. Don't allow that, as the implementation relies
+            # on always having a selected node.
+            _show_all = True
+            return
+
+    _shown = new_shown
+
+    # Try to make the cursor stay on the same row in the menu window. This
+    # might be impossible if too many nodes have disappeared above the node.
+    _menu_scroll = max(_sel_node_i - old_row, 0)
+
+
+def _center_vertically():
+    # Centers the selected node vertically, if possible
+
+    global _menu_scroll
+
+    _menu_scroll = min(max(_sel_node_i - _height(_menu_win)//2, 0),
+                       _max_scroll(_shown, _menu_win))
+
+
+def _draw_main():
+    # Draws the "main" display, with the list of symbols, the header, and the
+    # footer.
+    #
+    # This could be optimized to only update the windows that have actually
+    # changed, but keep it simple for now and let curses sort it out.
+
+    term_width = _width(_stdscr)
+
+    #
+    # Update the separator row below the menu path
+    #
+
+    _top_sep_win.erase()
+
+    # Draw arrows pointing up if the symbol window is scrolled down. Draw them
+    # before drawing the title, so the title ends up on top for small windows.
+    if _menu_scroll > 0:
+        _safe_hline(_top_sep_win, 0, 4, curses.ACS_UARROW, _N_SCROLL_ARROWS)
+
+    # Add the 'mainmenu' text as the title, centered at the top
+    _safe_addstr(_top_sep_win,
+                 0, max((term_width - len(_kconf.mainmenu_text))//2, 0),
+                 _kconf.mainmenu_text)
+
+    _top_sep_win.noutrefresh()
+
+    # Note: The menu path at the top is deliberately updated last. See below.
+
+    #
+    # Update the symbol window
+    #
+
+    _menu_win.erase()
+
+    # Draw the _shown nodes starting from index _menu_scroll up to either as
+    # many as fit in the window, or to the end of _shown
+    for i in range(_menu_scroll,
+                   min(_menu_scroll + _height(_menu_win), len(_shown))):
+
+        node = _shown[i]
+
+        # The 'not _show_all' test avoids showing invisible items in red
+        # outside show-all mode, which could look confusing/broken. Invisible
+        # symbols show up outside show-all mode if an invisible symbol has
+        # visible children in an implicit (indented) menu.
+        if _visible(node) or not _show_all:
+            style = _style["selection" if i == _sel_node_i else "list"]
+        else:
+            style = _style["inv-selection" if i == _sel_node_i else "inv-list"]
+
+        _safe_addstr(_menu_win, i - _menu_scroll, 0, _node_str(node), style)
+
+    _menu_win.noutrefresh()
+
+    #
+    # Update the bottom separator window
+    #
+
+    _bot_sep_win.erase()
+
+    # Draw arrows pointing down if the symbol window is scrolled up
+    if _menu_scroll < _max_scroll(_shown, _menu_win):
+        _safe_hline(_bot_sep_win, 0, 4, curses.ACS_DARROW, _N_SCROLL_ARROWS)
+
+    # Indicate when show-name/show-help/show-all mode is enabled
+    enabled_modes = []
+    if _show_help:
+        enabled_modes.append("show-help (toggle with [F])")
+    if _show_name:
+        enabled_modes.append("show-name")
+    if _show_all:
+        enabled_modes.append("show-all")
+    if enabled_modes:
+        s = " and ".join(enabled_modes) + " mode enabled"
+        _safe_addstr(_bot_sep_win, 0, max(term_width - len(s) - 2, 0), s)
+
+    _bot_sep_win.noutrefresh()
+
+    #
+    # Update the help window, which shows either key bindings or help texts
+    #
+
+    _help_win.erase()
+
+    if _show_help:
+        node = _shown[_sel_node_i]
+        if isinstance(node.item, (Symbol, Choice)) and node.help:
+            help_lines = textwrap.wrap(node.help, _width(_help_win))
+            for i in range(min(_height(_help_win), len(help_lines))):
+                _safe_addstr(_help_win, i, 0, help_lines[i])
+        else:
+            _safe_addstr(_help_win, 0, 0, "(no help)")
+    else:
+        for i, line in enumerate(_MAIN_HELP_LINES):
+            _safe_addstr(_help_win, i, 0, line)
+
+    _help_win.noutrefresh()
+
+    #
+    # Update the top row with the menu path.
+    #
+    # Doing this last leaves the cursor on the top row, which avoids some minor
+    # annoying jumpiness in gnome-terminal when reducing the height of the
+    # terminal. It seems to happen whenever the row with the cursor on it
+    # disappears.
+    #
+
+    _path_win.erase()
+
+    # Draw the menu path ("(Top) -> Menu -> Submenu -> ...")
+
+    menu_prompts = []
+
+    menu = _cur_menu
+    while menu is not _kconf.top_node:
+        # Promptless choices can be entered in show-all mode. Use
+        # standard_sc_expr_str() for them, so they show up as
+        # '<choice (name if any)>'.
+        menu_prompts.append(menu.prompt[0] if menu.prompt else
+                            standard_sc_expr_str(menu.item))
+        menu = menu.parent
+    menu_prompts.append("(Top)")
+    menu_prompts.reverse()
+
+    # Hack: We can't put ACS_RARROW directly in the string. Temporarily
+    # represent it with NULL.
+    menu_path_str = " \0 ".join(menu_prompts)
+
+    # Scroll the menu path to the right if needed to make the current menu's
+    # title visible
+    if len(menu_path_str) > term_width:
+        menu_path_str = menu_path_str[len(menu_path_str) - term_width:]
+
+    # Print the path with the arrows reinserted
+    split_path = menu_path_str.split("\0")
+    _safe_addstr(_path_win, split_path[0])
+    for s in split_path[1:]:
+        _safe_addch(_path_win, curses.ACS_RARROW)
+        _safe_addstr(_path_win, s)
+
+    _path_win.noutrefresh()
+
+
+def _parent_menu(node):
+    # Returns the menu node of the menu that contains 'node'. In addition to
+    # proper 'menu's, this might also be a 'menuconfig' symbol or a 'choice'.
+    # "Menu" here means a menu in the interface.
+
+    menu = node.parent
+    while not menu.is_menuconfig:
+        menu = menu.parent
+    return menu
+
+
+def _shown_nodes(menu):
+    # Returns the list of menu nodes from 'menu' (see _parent_menu()) that
+    # would be shown when entering it
+
+    def rec(node):
+        res = []
+
+        while node:
+            if _visible(node) or _show_all:
+                res.append(node)
+                if node.list and not node.is_menuconfig:
+                    # Nodes from implicit menu created from dependencies. Will
+                    # be shown indented. Note that is_menuconfig is True for
+                    # menus and choices as well as 'menuconfig' symbols.
+                    res += rec(node.list)
+
+            elif node.list and isinstance(node.item, Symbol):
+                # Show invisible symbols if they have visible children. This
+                # can happen for an m/y-valued symbol with an optional prompt
+                # ('prompt "foo" is COND') that is currently disabled. Note
+                # that it applies to both 'config' and 'menuconfig' symbols.
+                shown_children = rec(node.list)
+                if shown_children:
+                    res.append(node)
+                    if not node.is_menuconfig:
+                        res += shown_children
+
+            node = node.next
+
+        return res
+
+    if isinstance(menu.item, Choice):
+        # For named choices defined in multiple locations, entering the choice
+        # at a particular menu node would normally only show the choice symbols
+        # defined there (because that's what the MenuNode tree looks like).
+        #
+        # That might look confusing, and makes extending choices by defining
+        # them in multiple locations less useful. Instead, gather all the child
+        # menu nodes for all the choices whenever a choice is entered. That
+        # makes all choice symbols visible at all locations.
+        #
+        # Choices can contain non-symbol items (people do all sorts of weird
+        # stuff with them), hence the generality here. We really need to
+        # preserve the menu tree at each choice location.
+        #
+        # Note: Named choices are pretty broken in the C tools, and this is
+        # super obscure, so you probably won't find much that relies on this.
+        # This whole 'if' could be deleted if you don't care about defining
+        # choices in multiple locations to add symbols (which will still work,
+        # just with things being displayed in a way that might be unexpected).
+
+        # Do some additional work to avoid listing choice symbols twice if all
+        # or part of the choice is copied in multiple locations (e.g. by
+        # including some Kconfig file multiple times). We give the prompts at
+        # the current location precedence.
+        seen_syms = {node.item for node in rec(menu.list)
+                     if isinstance(node.item, Symbol)}
+        res = []
+        for choice_node in menu.item.nodes:
+            for node in rec(choice_node.list):
+                # 'choice_node is menu' checks if we're dealing with the
+                # current location
+                if node.item not in seen_syms or choice_node is menu:
+                    res.append(node)
+                    if isinstance(node.item, Symbol):
+                        seen_syms.add(node.item)
+        return res
+
+    return rec(menu.list)
+
+
+def _visible(node):
+    # Returns True if the node should appear in the menu (outside show-all
+    # mode)
+
+    return node.prompt and expr_value(node.prompt[1]) and not \
+        (node.item == MENU and not expr_value(node.visibility))
+
+
+def _change_node(node):
+    # Changes the value of the menu node 'node' if it is a symbol. Bools and
+    # tristates are toggled, while other symbol types pop up a text entry
+    # dialog.
+    #
+    # Returns False if the value of 'node' can't be changed.
+
+    if not _changeable(node):
+        return False
+
+    # sc = symbol/choice
+    sc = node.item
+
+    if sc.orig_type in (INT, HEX, STRING):
+        s = sc.str_value
+
+        while True:
+            s = _input_dialog(
+                "{} ({})".format(node.prompt[0], TYPE_TO_STR[sc.orig_type]),
+                s, _range_info(sc))
+
+            if s is None:
+                break
+
+            if sc.orig_type in (INT, HEX):
+                s = s.strip()
+
+                # 'make menuconfig' does this too. Hex values not starting with
+                # '0x' are accepted when loading .config files though.
+                if sc.orig_type == HEX and not s.startswith(("0x", "0X")):
+                    s = "0x" + s
+
+            if _check_valid(sc, s):
+                _set_val(sc, s)
+                break
+
+    elif len(sc.assignable) == 1:
+        # Handles choice symbols for choices in y mode, which are a special
+        # case: .assignable can be (2,) while .tri_value is 0.
+        _set_val(sc, sc.assignable[0])
+
+    else:
+        # Set the symbol to the value after the current value in
+        # sc.assignable, with wrapping
+        val_index = sc.assignable.index(sc.tri_value)
+        _set_val(sc, sc.assignable[(val_index + 1) % len(sc.assignable)])
+
+
+    if _is_y_mode_choice_sym(sc) and not node.list:
+        # Immediately jump to the parent menu after making a choice selection,
+        # like 'make menuconfig' does, except if the menu node has children
+        # (which can happen if a symbol 'depends on' a choice symbol that
+        # immediately precedes it).
+        _leave_menu()
+
+
+    return True
+
+
+def _changeable(node):
+    # Returns True if the value if 'node' can be changed
+
+    sc = node.item
+
+    if not isinstance(sc, (Symbol, Choice)):
+        return False
+
+    # This will hit for invisible symbols, which appear in show-all mode and
+    # when an invisible symbol has visible children (which can happen e.g. for
+    # symbols with optional prompts)
+    if not (node.prompt and expr_value(node.prompt[1])):
+        return False
+
+    return sc.orig_type in (STRING, INT, HEX) or len(sc.assignable) > 1 \
+        or _is_y_mode_choice_sym(sc)
+
+
+def _set_sel_node_tri_val(tri_val):
+    # Sets the value of the currently selected menu entry to 'tri_val', if that
+    # value can be assigned
+
+    sc = _shown[_sel_node_i].item
+    if isinstance(sc, (Symbol, Choice)) and tri_val in sc.assignable:
+        _set_val(sc, tri_val)
+
+
+def _set_val(sc, val):
+    # Wrapper around Symbol/Choice.set_value() for updating the menu state and
+    # _conf_changed
+
+    global _conf_changed
+
+    # Use the string representation of tristate values. This makes the format
+    # consistent for all symbol types.
+    if val in TRI_TO_STR:
+        val = TRI_TO_STR[val]
+
+    if val != sc.str_value:
+        sc.set_value(val)
+        _conf_changed = True
+
+        # Changing the value of the symbol might have changed what items in the
+        # current menu are visible. Recalculate the state.
+        _update_menu()
+
+
+def _update_menu():
+    # Updates the current menu after the value of a symbol or choice has been
+    # changed. Changing a value might change which items in the menu are
+    # visible.
+    #
+    # If possible, preserves the location of the cursor on the screen when
+    # items are added/removed above the selected item.
+
+    global _shown
+    global _sel_node_i
+    global _menu_scroll
+
+    # Row on the screen the cursor was on
+    old_row = _sel_node_i - _menu_scroll
+
+    sel_node = _shown[_sel_node_i]
+
+    # New visible nodes
+    _shown = _shown_nodes(_cur_menu)
+
+    # New index of selected node
+    _sel_node_i = _shown.index(sel_node)
+
+    # Try to make the cursor stay on the same row in the menu window. This
+    # might be impossible if too many nodes have disappeared above the node.
+    _menu_scroll = max(_sel_node_i - old_row, 0)
+
+
+def _input_dialog(title, initial_text, info_text=None):
+    # Pops up a dialog that prompts the user for a string
+    #
+    # title:
+    #   Title to display at the top of the dialog window's border
+    #
+    # initial_text:
+    #   Initial text to prefill the input field with
+    #
+    # info_text:
+    #   String to show next to the input field. If None, just the input field
+    #   is shown.
+
+    win = _styled_win("body")
+    win.keypad(True)
+
+    info_lines = info_text.split("\n") if info_text else []
+
+    # Give the input dialog its initial size
+    _resize_input_dialog(win, title, info_lines)
+
+    _safe_curs_set(2)
+
+    # Input field text
+    s = initial_text
+
+    # Cursor position
+    i = len(initial_text)
+
+    def edit_width():
+        return _width(win) - 4
+
+    # Horizontal scroll offset
+    hscroll = max(i - edit_width() + 1, 0)
+
+    while True:
+        # Draw the "main" display with the menu, etc., so that resizing still
+        # works properly. This is like a stack of windows, only hardcoded for
+        # now.
+        _draw_main()
+        _draw_input_dialog(win, title, info_lines, s, i, hscroll)
+        curses.doupdate()
+
+
+        c = _getch_compat(win)
+
+        if c == curses.KEY_RESIZE:
+            # Resize the main display too. The dialog floats above it.
+            _resize_main()
+            _resize_input_dialog(win, title, info_lines)
+
+        elif c == "\n":
+            _safe_curs_set(0)
+            return s
+
+        elif c == "\x1B":  # \x1B = ESC
+            _safe_curs_set(0)
+            return None
+
+        else:
+            s, i, hscroll = _edit_text(c, s, i, hscroll, edit_width())
+
+
+def _resize_input_dialog(win, title, info_lines):
+    # Resizes the input dialog to a size appropriate for the terminal size
+
+    screen_height, screen_width = _stdscr.getmaxyx()
+
+    win_height = 5
+    if info_lines:
+        win_height += len(info_lines) + 1
+    win_height = min(win_height, screen_height)
+
+    win_width = max(_INPUT_DIALOG_MIN_WIDTH,
+                    len(title) + 4,
+                    *(len(line) + 4 for line in info_lines))
+    win_width = min(win_width, screen_width)
+
+    win.resize(win_height, win_width)
+    win.mvwin((screen_height - win_height)//2,
+              (screen_width - win_width)//2)
+
+
+def _draw_input_dialog(win, title, info_lines, s, i, hscroll):
+    edit_width = _width(win) - 4
+
+    win.erase()
+
+    # Note: Perhaps having a separate window for the input field would be nicer
+    visible_s = s[hscroll:hscroll + edit_width]
+    _safe_addstr(win, 2, 2, visible_s + " "*(edit_width - len(visible_s)),
+                 _style["edit"])
+
+    for linenr, line in enumerate(info_lines):
+        _safe_addstr(win, 4 + linenr, 2, line)
+
+    # Draw the frame last so that it overwrites the body text for small windows
+    _draw_frame(win, title)
+
+    _safe_move(win, 2, 2 + i - hscroll)
+
+    win.noutrefresh()
+
+
+def _load_dialog():
+    # Dialog for loading a new configuration
+
+    global _conf_changed
+    global _conf_filename
+    global _show_all
+
+    if _conf_changed:
+        c = _key_dialog(
+            "Load",
+            "You have unsaved changes. Load new\n"
+            "configuration anyway?\n"
+            "\n"
+            "         (O)K  (C)ancel",
+            "oc")
+
+        if c is None or c == "c":
+            return
+
+    filename = _conf_filename
+    while True:
+        filename = _input_dialog("File to load", filename, _load_save_info())
+        if filename is None:
+            return
+
+        filename = os.path.expanduser(filename)
+
+        if _try_load(filename):
+            _conf_filename = filename
+            _conf_changed = _needs_save()
+
+            # Turn on show-all mode if the selected node is not visible after
+            # loading the new configuration. _shown still holds the old state.
+            if _shown[_sel_node_i] not in _shown_nodes(_cur_menu):
+                _show_all = True
+
+            _update_menu()
+
+            # The message dialog indirectly updates the menu display, so _msg()
+            # must be called after the new state has been initialized
+            _msg("Success", "Loaded " + filename)
+            return
+
+
+def _try_load(filename):
+    # Tries to load a configuration file. Pops up an error and returns False on
+    # failure.
+    #
+    # filename:
+    #   Configuration file to load
+
+    try:
+        _kconf.load_config(filename)
+        return True
+    except EnvironmentError as e:
+        _error("Error loading '{}'\n\n{} (errno: {})"
+               .format(filename, e.strerror, errno.errorcode[e.errno]))
+        return False
+
+
+def _save_dialog(save_fn, default_filename, description):
+    # Dialog for saving the current configuration
+    #
+    # save_fn:
+    #   Function to call with 'filename' to save the file
+    #
+    # default_filename:
+    #   Prefilled filename in the input field
+    #
+    # description:
+    #   String describing the thing being saved
+    #
+    # Return value:
+    #   The path to the saved file, or None if no file was saved
+
+    filename = default_filename
+    while True:
+        filename = _input_dialog("Filename to save {} to".format(description),
+                                 filename, _load_save_info())
+        if filename is None:
+            return None
+
+        filename = os.path.expanduser(filename)
+
+        msg = _try_save(save_fn, filename, description)
+        if msg:
+            _msg("Success", msg)
+            return filename
+
+
+def _try_save(save_fn, filename, description):
+    # Tries to save a configuration file. Returns a message to print on
+    # success.
+    #
+    # save_fn:
+    #   Function to call with 'filename' to save the file
+    #
+    # description:
+    #   String describing the thing being saved
+    #
+    # Return value:
+    #   A message to print on success, and None on failure
+
+    try:
+        # save_fn() returns a message to print
+        return save_fn(filename)
+    except EnvironmentError as e:
+        _error("Error saving {} to '{}'\n\n{} (errno: {})"
+               .format(description, e.filename, e.strerror,
+                       errno.errorcode[e.errno]))
+        return None
+
+
+def _key_dialog(title, text, keys):
+    # Pops up a dialog that can be closed by pressing a key
+    #
+    # title:
+    #   Title to display at the top of the dialog window's border
+    #
+    # text:
+    #   Text to show in the dialog
+    #
+    # keys:
+    #   List of keys that will close the dialog. Other keys (besides ESC) are
+    #   ignored. The caller is responsible for providing a hint about which
+    #   keys can be pressed in 'text'.
+    #
+    # Return value:
+    #   The key that was pressed to close the dialog. Uppercase characters are
+    #   converted to lowercase. ESC will always close the dialog, and returns
+    #   None.
+
+    win = _styled_win("body")
+    win.keypad(True)
+
+    _resize_key_dialog(win, text)
+
+    while True:
+        # See _input_dialog()
+        _draw_main()
+        _draw_key_dialog(win, title, text)
+        curses.doupdate()
+
+
+        c = _getch_compat(win)
+
+        if c == curses.KEY_RESIZE:
+            # Resize the main display too. The dialog floats above it.
+            _resize_main()
+            _resize_key_dialog(win, text)
+
+        elif c == "\x1B":  # \x1B = ESC
+            return None
+
+        elif isinstance(c, str):
+            c = c.lower()
+            if c in keys:
+                return c
+
+
+def _resize_key_dialog(win, text):
+    # Resizes the key dialog to a size appropriate for the terminal size
+
+    screen_height, screen_width = _stdscr.getmaxyx()
+
+    lines = text.split("\n")
+
+    win_height = min(len(lines) + 4, screen_height)
+    win_width = min(max(len(line) for line in lines) + 4, screen_width)
+
+    win.resize(win_height, win_width)
+    win.mvwin((screen_height - win_height)//2,
+              (screen_width - win_width)//2)
+
+
+def _draw_key_dialog(win, title, text):
+    win.erase()
+
+    for i, line in enumerate(text.split("\n")):
+        _safe_addstr(win, 2 + i, 2, line)
+
+    # Draw the frame last so that it overwrites the body text for small windows
+    _draw_frame(win, title)
+
+    win.noutrefresh()
+
+
+def _draw_frame(win, title):
+    # Draw a frame around the inner edges of 'win', with 'title' at the top
+
+    win_height, win_width = win.getmaxyx()
+
+    win.attron(_style["frame"])
+
+    # Draw top/bottom edge
+    _safe_hline(win,              0, 0, " ", win_width)
+    _safe_hline(win, win_height - 1, 0, " ", win_width)
+
+    # Draw left/right edge
+    _safe_vline(win, 0,             0, " ", win_height)
+    _safe_vline(win, 0, win_width - 1, " ", win_height)
+
+    # Draw title
+    _safe_addstr(win, 0, max((win_width - len(title))//2, 0), title)
+
+    win.attroff(_style["frame"])
+
+
+def _jump_to_dialog():
+    # Implements the jump-to dialog, where symbols can be looked up via
+    # incremental search and jumped to.
+    #
+    # Returns True if the user jumped to a symbol, and False if the dialog was
+    # canceled.
+
+    s = ""  # Search text
+    prev_s = None  # Previous search text
+    s_i = 0  # Search text cursor position
+    hscroll = 0  # Horizontal scroll offset
+
+    sel_node_i = 0  # Index of selected row
+    scroll = 0  # Index in 'matches' of the top row of the list
+
+    # Edit box at the top
+    edit_box = _styled_win("jump-edit")
+    edit_box.keypad(True)
+
+    # List of matches
+    matches_win = _styled_win("list")
+
+    # Bottom separator, with arrows pointing down
+    bot_sep_win = _styled_win("separator")
+
+    # Help window with instructions at the bottom
+    help_win = _styled_win("help")
+
+    # Give windows their initial size
+    _resize_jump_to_dialog(edit_box, matches_win, bot_sep_win, help_win,
+                           sel_node_i, scroll)
+
+    _safe_curs_set(2)
+
+    # Logic duplication with _select_{next,prev}_menu_entry(), except we do a
+    # functional variant that returns the new (sel_node_i, scroll) values to
+    # avoid 'nonlocal'. TODO: Can this be factored out in some nice way?
+
+    def select_next_match():
+        if sel_node_i == len(matches) - 1:
+            return sel_node_i, scroll
+
+        if sel_node_i + 1 >= scroll + _height(matches_win) - _SCROLL_OFFSET \
+           and scroll < _max_scroll(matches, matches_win):
+
+            return sel_node_i + 1, scroll + 1
+
+        return sel_node_i + 1, scroll
+
+    def select_prev_match():
+        if sel_node_i == 0:
+            return sel_node_i, scroll
+
+        if sel_node_i - 1 < scroll + _SCROLL_OFFSET:
+            return sel_node_i - 1, max(scroll - 1, 0)
+
+        return sel_node_i - 1, scroll
+
+    while True:
+        if s != prev_s:
+            # The search text changed. Find new matching nodes.
+
+            prev_s = s
+
+            try:
+                # We could use re.IGNORECASE here instead of lower(), but this
+                # is noticeably less jerky while inputting regexes like
+                # '.*debug$' (though the '.*' is redundant there). Those
+                # probably have bad interactions with re.search(), which
+                # matches anywhere in the string.
+                #
+                # It's not horrible either way. Just a bit smoother.
+                regex_searches = [re.compile(regex).search
+                                  for regex in s.lower().split()]
+
+                # No exception thrown, so the regexes are okay
+                bad_re = None
+
+                # List of matching nodes
+                matches = []
+                add_match = matches.append
+
+                # Search symbols and choices
+
+                for node in _sorted_sc_nodes():
+                    # Symbol/choice
+                    sc = node.item
+
+                    for search in regex_searches:
+                        # Both the name and the prompt might be missing, since
+                        # we're searching both symbols and choices
+
+                        # Does the regex match either the symbol name or the
+                        # prompt (if any)?
+                        if not (sc.name and search(sc.name.lower()) or
+                                node.prompt and search(node.prompt[0].lower())):
+
+                            # Give up on the first regex that doesn't match, to
+                            # speed things up a bit when multiple regexes are
+                            # entered
+                            break
+
+                    else:
+                        add_match(node)
+
+                # Search menus and comments
+
+                for node in _sorted_menu_comment_nodes():
+                    for search in regex_searches:
+                        if not search(node.prompt[0].lower()):
+                            break
+                    else:
+                        add_match(node)
+
+            except re.error as e:
+                # Bad regex. Remember the error message so we can show it.
+                bad_re = "Bad regular expression"
+                # re.error.msg was added in Python 3.5
+                if hasattr(e, "msg"):
+                    bad_re += ": " + e.msg
+
+                matches = []
+
+            # Reset scroll and jump to the top of the list of matches
+            sel_node_i = scroll = 0
+
+        _draw_jump_to_dialog(edit_box, matches_win, bot_sep_win, help_win,
+                             s, s_i, hscroll,
+                             bad_re, matches, sel_node_i, scroll)
+        curses.doupdate()
+
+
+        c = _getch_compat(edit_box)
+
+        if c == "\n":
+            if matches:
+                _jump_to(matches[sel_node_i])
+                _safe_curs_set(0)
+                return True
+
+        elif c == "\x1B":  # \x1B = ESC
+            _safe_curs_set(0)
+            return False
+
+        elif c == curses.KEY_RESIZE:
+            # We adjust the scroll so that the selected node stays visible in
+            # the list when the terminal is resized, hence the 'scroll'
+            # assignment
+            scroll = _resize_jump_to_dialog(
+                edit_box, matches_win, bot_sep_win, help_win,
+                sel_node_i, scroll)
+
+        elif c == "\x06":  # \x06 = Ctrl-F
+            if matches:
+                _safe_curs_set(0)
+                _info_dialog(matches[sel_node_i], True)
+                _safe_curs_set(2)
+
+                scroll = _resize_jump_to_dialog(
+                    edit_box, matches_win, bot_sep_win, help_win,
+                    sel_node_i, scroll)
+
+        elif c == curses.KEY_DOWN:
+            sel_node_i, scroll = select_next_match()
+
+        elif c == curses.KEY_UP:
+            sel_node_i, scroll = select_prev_match()
+
+        elif c in (curses.KEY_NPAGE, "\x04"):  # Page Down/Ctrl-D
+            # Keep it simple. This way we get sane behavior for small windows,
+            # etc., for free.
+            for _ in range(_PG_JUMP):
+                sel_node_i, scroll = select_next_match()
+
+        # Page Up (no Ctrl-U, as it's already used by the edit box)
+        elif c == curses.KEY_PPAGE:
+            for _ in range(_PG_JUMP):
+                sel_node_i, scroll = select_prev_match()
+
+        elif c == curses.KEY_END:
+            sel_node_i = len(matches) - 1
+            scroll = _max_scroll(matches, matches_win)
+
+        elif c == curses.KEY_HOME:
+            sel_node_i = scroll = 0
+
+        else:
+            s, s_i, hscroll = _edit_text(c, s, s_i, hscroll,
+                                         _width(edit_box) - 2)
+
+
+# Obscure Python: We never pass a value for cached_nodes, and it keeps pointing
+# to the same list. This avoids a global.
+def _sorted_sc_nodes(cached_nodes=[]):
+    # Returns a sorted list of symbol and choice nodes to search. The symbol
+    # nodes appear first, sorted by name, and then the choice nodes, sorted by
+    # prompt and (secondarily) name.
+
+    if not cached_nodes:
+        # Add symbol nodes
+        for sym in sorted(_kconf.unique_defined_syms,
+                          key=lambda sym: sym.name):
+            # += is in-place for lists
+            cached_nodes += sym.nodes
+
+        # Add choice nodes
+
+        choices = sorted(_kconf.unique_choices,
+                         key=lambda choice: choice.name or "")
+
+        cached_nodes += sorted(
+            [node for choice in choices for node in choice.nodes],
+            key=lambda node: node.prompt[0] if node.prompt else "")
+
+    return cached_nodes
+
+
+def _sorted_menu_comment_nodes(cached_nodes=[]):
+    # Returns a list of menu and comment nodes to search, sorted by prompt,
+    # with the menus first
+
+    if not cached_nodes:
+        def prompt_text(mc):
+            return mc.prompt[0]
+
+        cached_nodes += sorted(_kconf.menus, key=prompt_text)
+        cached_nodes += sorted(_kconf.comments, key=prompt_text)
+
+    return cached_nodes
+
+
+def _resize_jump_to_dialog(edit_box, matches_win, bot_sep_win, help_win,
+                           sel_node_i, scroll):
+    # Resizes the jump-to dialog to fill the terminal.
+    #
+    # Returns the new scroll index. We adjust the scroll if needed so that the
+    # selected node stays visible.
+
+    screen_height, screen_width = _stdscr.getmaxyx()
+
+    bot_sep_win.resize(1, screen_width)
+
+    help_win_height = len(_JUMP_TO_HELP_LINES)
+    matches_win_height = screen_height - help_win_height - 4
+
+    if matches_win_height >= 1:
+        edit_box.resize(3, screen_width)
+        matches_win.resize(matches_win_height, screen_width)
+        help_win.resize(help_win_height, screen_width)
+
+        matches_win.mvwin(3, 0)
+        bot_sep_win.mvwin(3 + matches_win_height, 0)
+        help_win.mvwin(3 + matches_win_height + 1, 0)
+    else:
+        # Degenerate case. Give up on nice rendering and just prevent errors.
+
+        matches_win_height = 1
+
+        edit_box.resize(screen_height, screen_width)
+        matches_win.resize(1, screen_width)
+        help_win.resize(1, screen_width)
+
+        for win in matches_win, bot_sep_win, help_win:
+            win.mvwin(0, 0)
+
+    # Adjust the scroll so that the selected row is still within the window, if
+    # needed
+    if sel_node_i - scroll >= matches_win_height:
+        return sel_node_i - matches_win_height + 1
+    return scroll
+
+
+def _draw_jump_to_dialog(edit_box, matches_win, bot_sep_win, help_win,
+                         s, s_i, hscroll,
+                         bad_re, matches, sel_node_i, scroll):
+
+    edit_width = _width(edit_box) - 2
+
+    #
+    # Update list of matches
+    #
+
+    matches_win.erase()
+
+    if matches:
+        for i in range(scroll,
+                       min(scroll + _height(matches_win), len(matches))):
+
+            node = matches[i]
+
+            if isinstance(node.item, (Symbol, Choice)):
+                node_str = _name_and_val_str(node.item)
+                if node.prompt:
+                    node_str += ' "{}"'.format(node.prompt[0])
+            elif node.item == MENU:
+                node_str = 'menu "{}"'.format(node.prompt[0])
+            else:  # node.item == COMMENT
+                node_str = 'comment "{}"'.format(node.prompt[0])
+
+            _safe_addstr(matches_win, i - scroll, 0, node_str,
+                         _style["selection" if i == sel_node_i else "list"])
+
+    else:
+        # bad_re holds the error message from the re.error exception on errors
+        _safe_addstr(matches_win, 0, 0, bad_re or "No matches")
+
+    matches_win.noutrefresh()
+
+    #
+    # Update bottom separator line
+    #
+
+    bot_sep_win.erase()
+
+    # Draw arrows pointing down if the symbol list is scrolled up
+    if scroll < _max_scroll(matches, matches_win):
+        _safe_hline(bot_sep_win, 0, 4, curses.ACS_DARROW, _N_SCROLL_ARROWS)
+
+    bot_sep_win.noutrefresh()
+
+    #
+    # Update help window at bottom
+    #
+
+    help_win.erase()
+
+    for i, line in enumerate(_JUMP_TO_HELP_LINES):
+        _safe_addstr(help_win, i, 0, line)
+
+    help_win.noutrefresh()
+
+    #
+    # Update edit box. We do this last since it makes it handy to position the
+    # cursor.
+    #
+
+    edit_box.erase()
+
+    _draw_frame(edit_box, "Jump to symbol/choice/menu/comment")
+
+    # Draw arrows pointing up if the symbol list is scrolled down
+    if scroll > 0:
+        # TODO: Bit ugly that _style["frame"] is repeated here
+        _safe_hline(edit_box, 2, 4, curses.ACS_UARROW, _N_SCROLL_ARROWS,
+                    _style["frame"])
+
+    visible_s = s[hscroll:hscroll + edit_width]
+    _safe_addstr(edit_box, 1, 1, visible_s)
+
+    _safe_move(edit_box, 1, 1 + s_i - hscroll)
+
+    edit_box.noutrefresh()
+
+
+def _info_dialog(node, from_jump_to_dialog):
+    # Shows a fullscreen window with information about 'node'.
+    #
+    # If 'from_jump_to_dialog' is True, the information dialog was opened from
+    # within the jump-to-dialog. In this case, we make '/' from within the
+    # information dialog just return, to avoid a confusing recursive invocation
+    # of the jump-to-dialog.
+
+    # Top row, with title and arrows point up
+    top_line_win = _styled_win("separator")
+
+    # Text display
+    text_win = _styled_win("text")
+    text_win.keypad(True)
+
+    # Bottom separator, with arrows pointing down
+    bot_sep_win = _styled_win("separator")
+
+    # Help window with keys at the bottom
+    help_win = _styled_win("help")
+
+    # Give windows their initial size
+    _resize_info_dialog(top_line_win, text_win, bot_sep_win, help_win)
+
+
+    # Get lines of help text
+    lines = _info_str(node).split("\n")
+
+    # Index of first row in 'lines' to show
+    scroll = 0
+
+    while True:
+        _draw_info_dialog(node, lines, scroll, top_line_win, text_win,
+                          bot_sep_win, help_win)
+        curses.doupdate()
+
+
+        c = _getch_compat(text_win)
+
+        if c == curses.KEY_RESIZE:
+            _resize_info_dialog(top_line_win, text_win, bot_sep_win, help_win)
+
+        elif c in (curses.KEY_DOWN, "j", "J"):
+            if scroll < _max_scroll(lines, text_win):
+                scroll += 1
+
+        elif c in (curses.KEY_NPAGE, "\x04"):  # Page Down/Ctrl-D
+            scroll = min(scroll + _PG_JUMP, _max_scroll(lines, text_win))
+
+        elif c in (curses.KEY_PPAGE, "\x15"):  # Page Up/Ctrl-U
+            scroll = max(scroll - _PG_JUMP, 0)
+
+        elif c in (curses.KEY_END, "G"):
+            scroll = _max_scroll(lines, text_win)
+
+        elif c in (curses.KEY_HOME, "g"):
+            scroll = 0
+
+        elif c in (curses.KEY_UP, "k", "K"):
+            if scroll > 0:
+                scroll -= 1
+
+        elif c == "/":
+            # Support starting a search from within the information dialog
+
+            if from_jump_to_dialog:
+                return  # Avoid recursion
+
+            if _jump_to_dialog():
+                return  # Jumped to a symbol. Cancel the information dialog.
+
+            # Stay in the information dialog if the jump-to dialog was
+            # canceled. Resize it in case the terminal was resized while the
+            # fullscreen jump-to dialog was open.
+            _resize_info_dialog(top_line_win, text_win, bot_sep_win, help_win)
+
+        elif c in (curses.KEY_LEFT, curses.KEY_BACKSPACE, _ERASE_CHAR,
+                   "\x1B",  # \x1B = ESC
+                   "q", "Q", "h", "H"):
+
+            return
+
+
+def _resize_info_dialog(top_line_win, text_win, bot_sep_win, help_win):
+    # Resizes the info dialog to fill the terminal
+
+    screen_height, screen_width = _stdscr.getmaxyx()
+
+    top_line_win.resize(1, screen_width)
+    bot_sep_win.resize(1, screen_width)
+
+    help_win_height = len(_INFO_HELP_LINES)
+    text_win_height = screen_height - help_win_height - 2
+
+    if text_win_height >= 1:
+        text_win.resize(text_win_height, screen_width)
+        help_win.resize(help_win_height, screen_width)
+
+        text_win.mvwin(1, 0)
+        bot_sep_win.mvwin(1 + text_win_height, 0)
+        help_win.mvwin(1 + text_win_height + 1, 0)
+    else:
+        # Degenerate case. Give up on nice rendering and just prevent errors.
+
+        text_win.resize(1, screen_width)
+        help_win.resize(1, screen_width)
+
+        for win in text_win, bot_sep_win, help_win:
+            win.mvwin(0, 0)
+
+
+def _draw_info_dialog(node, lines, scroll, top_line_win, text_win,
+                      bot_sep_win, help_win):
+
+    text_win_height, text_win_width = text_win.getmaxyx()
+
+    # Note: The top row is deliberately updated last. See _draw_main().
+
+    #
+    # Update text display
+    #
+
+    text_win.erase()
+
+    for i, line in enumerate(lines[scroll:scroll + text_win_height]):
+        _safe_addstr(text_win, i, 0, line)
+
+    text_win.noutrefresh()
+
+    #
+    # Update bottom separator line
+    #
+
+    bot_sep_win.erase()
+
+    # Draw arrows pointing down if the symbol window is scrolled up
+    if scroll < _max_scroll(lines, text_win):
+        _safe_hline(bot_sep_win, 0, 4, curses.ACS_DARROW, _N_SCROLL_ARROWS)
+
+    bot_sep_win.noutrefresh()
+
+    #
+    # Update help window at bottom
+    #
+
+    help_win.erase()
+
+    for i, line in enumerate(_INFO_HELP_LINES):
+        _safe_addstr(help_win, i, 0, line)
+
+    help_win.noutrefresh()
+
+    #
+    # Update top row
+    #
+
+    top_line_win.erase()
+
+    # Draw arrows pointing up if the information window is scrolled down. Draw
+    # them before drawing the title, so the title ends up on top for small
+    # windows.
+    if scroll > 0:
+        _safe_hline(top_line_win, 0, 4, curses.ACS_UARROW, _N_SCROLL_ARROWS)
+
+    title = ("Symbol" if isinstance(node.item, Symbol) else
+             "Choice" if isinstance(node.item, Choice) else
+             "Menu"   if node.item == MENU else
+             "Comment") + " information"
+    _safe_addstr(top_line_win, 0, max((text_win_width - len(title))//2, 0),
+                 title)
+
+    top_line_win.noutrefresh()
+
+
+def _info_str(node):
+    # Returns information about the menu node 'node' as a string.
+    #
+    # The helper functions are responsible for adding newlines. This allows
+    # them to return "" if they don't want to add any output.
+
+    if isinstance(node.item, Symbol):
+        sym = node.item
+
+        return (
+            _name_info(sym) +
+            _prompt_info(sym) +
+            "Type: {}\n".format(TYPE_TO_STR[sym.type]) +
+            _value_info(sym) +
+            _help_info(sym) +
+            _direct_dep_info(sym) +
+            _defaults_info(sym) +
+            _select_imply_info(sym) +
+            _kconfig_def_info(sym)
+        )
+
+    if isinstance(node.item, Choice):
+        choice = node.item
+
+        return (
+            _name_info(choice) +
+            _prompt_info(choice) +
+            "Type: {}\n".format(TYPE_TO_STR[choice.type]) +
+            'Mode: {}\n'.format(choice.str_value) +
+            _help_info(choice) +
+            _choice_syms_info(choice) +
+            _direct_dep_info(choice) +
+            _defaults_info(choice) +
+            _kconfig_def_info(choice)
+        )
+
+    return _kconfig_def_info(node)  # node.item in (MENU, COMMENT)
+
+
+def _name_info(sc):
+    # Returns a string with the name of the symbol/choice. Names are optional
+    # for choices.
+
+    return "Name: {}\n".format(sc.name) if sc.name else ""
+
+
+def _prompt_info(sc):
+    # Returns a string listing the prompts of 'sc' (Symbol or Choice)
+
+    s = ""
+
+    for node in sc.nodes:
+        if node.prompt:
+            s += "Prompt: {}\n".format(node.prompt[0])
+
+    return s
+
+
+def _value_info(sym):
+    # Returns a string showing 'sym's value
+
+    # Only put quotes around the value for string symbols
+    return "Value: {}\n".format(
+        '"{}"'.format(sym.str_value)
+        if sym.orig_type == STRING
+        else sym.str_value)
+
+
+def _choice_syms_info(choice):
+    # Returns a string listing the choice symbols in 'choice'. Adds
+    # "(selected)" next to the selected one.
+
+    s = "Choice symbols:\n"
+
+    for sym in choice.syms:
+        s += "  - " + sym.name
+        if sym is choice.selection:
+            s += " (selected)"
+        s += "\n"
+
+    return s + "\n"
+
+
+def _help_info(sc):
+    # Returns a string with the help text(s) of 'sc' (Symbol or Choice).
+    # Symbols and choices defined in multiple locations can have multiple help
+    # texts.
+
+    s = "\n"
+
+    for node in sc.nodes:
+        if node.help is not None:
+            s += "Help:\n\n{}\n\n".format(_indent(node.help, 2))
+
+    return s
+
+
+def _direct_dep_info(sc):
+    # Returns a string describing the direct dependencies of 'sc' (Symbol or
+    # Choice). The direct dependencies are the OR of the dependencies from each
+    # definition location. The dependencies at each definition location come
+    # from 'depends on' and dependencies inherited from parent items.
+
+    return "" if sc.direct_dep is _kconf.y else \
+        'Direct dependencies (={}):\n{}\n' \
+        .format(TRI_TO_STR[expr_value(sc.direct_dep)],
+                _split_expr_info(sc.direct_dep, 2))
+
+
+def _defaults_info(sc):
+    # Returns a string describing the defaults of 'sc' (Symbol or Choice)
+
+    if not sc.defaults:
+        return ""
+
+    s = "Default"
+    if len(sc.defaults) > 1:
+        s += "s"
+    s += ":\n"
+
+    for val, cond in sc.orig_defaults:
+        s += "  - "
+        if isinstance(sc, Symbol):
+            s += _expr_str(val)
+
+            # Skip the tristate value hint if the expression is just a single
+            # symbol. _expr_str() already shows its value as a string.
+            #
+            # This also avoids showing the tristate value for string/int/hex
+            # defaults, which wouldn't make any sense.
+            if isinstance(val, tuple):
+                s += '  (={})'.format(TRI_TO_STR[expr_value(val)])
+        else:
+            # Don't print the value next to the symbol name for choice
+            # defaults, as it looks a bit confusing
+            s += val.name
+        s += "\n"
+
+        if cond is not _kconf.y:
+            s += "    Condition (={}):\n{}" \
+                 .format(TRI_TO_STR[expr_value(cond)],
+                         _split_expr_info(cond, 4))
+
+    return s + "\n"
+
+
+def _split_expr_info(expr, indent):
+    # Returns a string with 'expr' split into its top-level && or || operands,
+    # with one operand per line, together with the operand's value. This is
+    # usually enough to get something readable for long expressions. A fancier
+    # recursive thingy would be possible too.
+    #
+    # indent:
+    #   Number of leading spaces to add before the split expression.
+
+    if len(split_expr(expr, AND)) > 1:
+        split_op = AND
+        op_str = "&&"
+    else:
+        split_op = OR
+        op_str = "||"
+
+    s = ""
+    for i, term in enumerate(split_expr(expr, split_op)):
+        s += "{}{} {}".format(indent*" ",
+                              "  " if i == 0 else op_str,
+                              _expr_str(term))
+
+        # Don't bother showing the value hint if the expression is just a
+        # single symbol. _expr_str() already shows its value.
+        if isinstance(term, tuple):
+            s += "  (={})".format(TRI_TO_STR[expr_value(term)])
+
+        s += "\n"
+
+    return s
+
+
+def _select_imply_info(sym):
+    # Returns a string with information about which symbols 'select' or 'imply'
+    # 'sym'. The selecting/implying symbols are grouped according to which
+    # value they select/imply 'sym' to (n/m/y).
+
+    def sis(expr, val, title):
+        # sis = selects/implies
+        sis = [si for si in split_expr(expr, OR) if expr_value(si) == val]
+        if not sis:
+            return ""
+
+        res = title
+        for si in sis:
+            res += "  - {}\n".format(split_expr(si, AND)[0].name)
+        return res + "\n"
+
+    s = ""
+
+    if sym.rev_dep is not _kconf.n:
+        s += sis(sym.rev_dep, 2,
+                 "Symbols currently y-selecting this symbol:\n")
+        s += sis(sym.rev_dep, 1,
+                 "Symbols currently m-selecting this symbol:\n")
+        s += sis(sym.rev_dep, 0,
+                 "Symbols currently n-selecting this symbol (no effect):\n")
+
+    if sym.weak_rev_dep is not _kconf.n:
+        s += sis(sym.weak_rev_dep, 2,
+                 "Symbols currently y-implying this symbol:\n")
+        s += sis(sym.weak_rev_dep, 1,
+                 "Symbols currently m-implying this symbol:\n")
+        s += sis(sym.weak_rev_dep, 0,
+                 "Symbols currently n-implying this symbol (no effect):\n")
+
+    return s
+
+
+def _kconfig_def_info(item):
+    # Returns a string with the definition of 'item' in Kconfig syntax,
+    # together with the definition location(s) and their include and menu paths
+
+    nodes = [item] if isinstance(item, MenuNode) else item.nodes
+
+    s = "Kconfig definition{}, with parent deps. propagated to 'depends on'\n" \
+        .format("s" if len(nodes) > 1 else "")
+    s += (len(s) - 1)*"="
+
+    for node in nodes:
+        s += "\n\n" \
+             "At {}:{}\n" \
+             "{}" \
+             "Menu path: {}\n\n" \
+             "{}" \
+             .format(node.filename, node.linenr,
+                     _include_path_info(node),
+                     _menu_path_info(node),
+                     _indent(node.custom_str(_name_and_val_str), 2))
+
+    return s
+
+
+def _include_path_info(node):
+    if not node.include_path:
+        # In the top-level Kconfig file
+        return ""
+
+    return "Included via {}\n".format(
+        " -> ".join("{}:{}".format(filename, linenr)
+                    for filename, linenr in node.include_path))
+
+
+def _menu_path_info(node):
+    # Returns a string describing the menu path leading up to 'node'
+
+    path = ""
+
+    while node.parent is not _kconf.top_node:
+        node = node.parent
+
+        # Promptless choices might appear among the parents. Use
+        # standard_sc_expr_str() for them, so that they show up as
+        # '<choice (name if any)>'.
+        path = " -> " + (node.prompt[0] if node.prompt else
+                         standard_sc_expr_str(node.item)) + path
+
+    return "(Top)" + path
+
+
+def _indent(s, n):
+    # Returns 's' with each line indented 'n' spaces. textwrap.indent() is not
+    # available in Python 2 (it's 3.3+).
+
+    return "\n".join(n*" " + line for line in s.split("\n"))
+
+
+def _name_and_val_str(sc):
+    # Custom symbol/choice printer that shows symbol values after symbols
+
+    # Show the values of non-constant (non-quoted) symbols that don't look like
+    # numbers. Things like 123 are actually symbol references, and only work as
+    # expected due to undefined symbols getting their name as their value.
+    # Showing the symbol value for those isn't helpful though.
+    if isinstance(sc, Symbol) and not sc.is_constant and not _is_num(sc.name):
+        if not sc.nodes:
+            # Undefined symbol reference
+            return "{}(undefined/n)".format(sc.name)
+
+        return '{}(={})'.format(sc.name, sc.str_value)
+
+    # For other items, use the standard format
+    return standard_sc_expr_str(sc)
+
+
+def _expr_str(expr):
+    # Custom expression printer that shows symbol values
+    return expr_str(expr, _name_and_val_str)
+
+
+def _styled_win(style):
+    # Returns a new curses window with style 'style' and space as the fill
+    # character. The initial dimensions are (1, 1), so the window needs to be
+    # sized and positioned separately.
+
+    win = curses.newwin(1, 1)
+    _set_style(win, style)
+    return win
+
+
+def _set_style(win, style):
+    # Changes the style of an existing window
+
+    win.bkgdset(" ", _style[style])
+
+
+def _max_scroll(lst, win):
+    # Assuming 'lst' is a list of items to be displayed in 'win',
+    # returns the maximum number of steps 'win' can be scrolled down.
+    # We stop scrolling when the bottom item is visible.
+
+    return max(0, len(lst) - _height(win))
+
+
+def _edit_text(c, s, i, hscroll, width):
+    # Implements text editing commands for edit boxes. Takes a character (which
+    # could also be e.g. curses.KEY_LEFT) and the edit box state, and returns
+    # the new state after the character has been processed.
+    #
+    # c:
+    #   Character from user
+    #
+    # s:
+    #   Current contents of string
+    #
+    # i:
+    #   Current cursor index in string
+    #
+    # hscroll:
+    #   Index in s of the leftmost character in the edit box, for horizontal
+    #   scrolling
+    #
+    # width:
+    #   Width in characters of the edit box
+    #
+    # Return value:
+    #   An (s, i, hscroll) tuple for the new state
+
+    if c == curses.KEY_LEFT:
+        if i > 0:
+            i -= 1
+
+    elif c == curses.KEY_RIGHT:
+        if i < len(s):
+            i += 1
+
+    elif c in (curses.KEY_HOME, "\x01"):  # \x01 = CTRL-A
+        i = 0
+
+    elif c in (curses.KEY_END, "\x05"):  # \x05 = CTRL-E
+        i = len(s)
+
+    elif c in (curses.KEY_BACKSPACE, _ERASE_CHAR):
+        if i > 0:
+            s = s[:i-1] + s[i:]
+            i -= 1
+
+    elif c == curses.KEY_DC:
+        s = s[:i] + s[i+1:]
+
+    elif c == "\x17":  # \x17 = CTRL-W
+        # The \W removes characters like ',' one at a time
+        new_i = re.search(r"(?:\w*|\W)\s*$", s[:i]).start()
+        s = s[:new_i] + s[i:]
+        i = new_i
+
+    elif c == "\x0B":  # \x0B = CTRL-K
+        s = s[:i]
+
+    elif c == "\x15":  # \x15 = CTRL-U
+        s = s[i:]
+        i = 0
+
+    elif isinstance(c, str):
+        # Insert character
+        s = s[:i] + c + s[i:]
+        i += 1
+
+    # Adjust the horizontal scroll so that the cursor never touches the left or
+    # right edges of the edit box, except when it's at the beginning or the end
+    # of the string
+    if i < hscroll + _SCROLL_OFFSET:
+        hscroll = max(i - _SCROLL_OFFSET, 0)
+    elif i >= hscroll + width - _SCROLL_OFFSET:
+        max_scroll = max(len(s) - width + 1, 0)
+        hscroll = min(i - width + _SCROLL_OFFSET + 1, max_scroll)
+
+    return s, i, hscroll
+
+
+def _load_save_info():
+    # Returns an information string for load/save dialog boxes
+
+    return "(Relative to {})\n\nRefer to your home directory with ~" \
+           .format(os.path.join(os.getcwd(), ""))
+
+
+def _msg(title, text):
+    # Pops up a message dialog that can be dismissed with Space/Enter/ESC
+
+    _key_dialog(title, text, " \n")
+
+
+def _error(text):
+    # Pops up an error dialog that can be dismissed with Space/Enter/ESC
+
+    _msg("Error", text)
+
+
+def _node_str(node):
+    # Returns the complete menu entry text for a menu node.
+    #
+    # Example return value: "[*] Support for X"
+
+    # Calculate the indent to print the item with by checking how many levels
+    # above it the closest 'menuconfig' item is (this includes menus and
+    # choices as well as menuconfig symbols)
+    indent = 0
+    parent = node.parent
+    while not parent.is_menuconfig:
+        indent += _SUBMENU_INDENT
+        parent = parent.parent
+
+    # This approach gives nice alignment for empty string symbols ("()  Foo")
+    s = "{:{}}".format(_value_str(node), 3 + indent)
+
+    if _should_show_name(node):
+        if isinstance(node.item, Symbol):
+            s += " <{}>".format(node.item.name)
+        else:
+            # For choices, use standard_sc_expr_str(). That way they show up as
+            # '<choice (name if any)>'.
+            s += " " + standard_sc_expr_str(node.item)
+
+    if node.prompt:
+        if node.item == COMMENT:
+            s += " *** {} ***".format(node.prompt[0])
+        else:
+            s += " " + node.prompt[0]
+
+        if isinstance(node.item, Symbol):
+            sym = node.item
+
+            # Print "(NEW)" next to symbols without a user value (from e.g. a
+            # .config), but skip it for choice symbols in choices in y mode,
+            # and for symbols of UNKNOWN type (which generate a warning though)
+            if sym.user_value is None and sym.orig_type and \
+               not (sym.choice and sym.choice.tri_value == 2):
+
+                s += " (NEW)"
+
+    if isinstance(node.item, Choice) and node.item.tri_value == 2:
+        # Print the prompt of the selected symbol after the choice for
+        # choices in y mode
+        sym = node.item.selection
+        if sym:
+            for sym_node in sym.nodes:
+                # Use the prompt used at this choice location, in case the
+                # choice symbol is defined in multiple locations
+                if sym_node.parent is node and sym_node.prompt:
+                    s += " ({})".format(sym_node.prompt[0])
+                    break
+            else:
+                # If the symbol isn't defined at this choice location, then
+                # just use whatever prompt we can find for it
+                for sym_node in sym.nodes:
+                    if sym_node.prompt:
+                        s += " ({})".format(sym_node.prompt[0])
+                        break
+
+    # Print "--->" next to nodes that have menus that can potentially be
+    # entered. Print "----" if the menu is empty. We don't allow those to be
+    # entered.
+    if node.is_menuconfig:
+        s += "  --->" if _shown_nodes(node) else "  ----"
+
+    return s
+
+
+def _should_show_name(node):
+    # Returns True if 'node' is a symbol or choice whose name should shown (if
+    # any, as names are optional for choices)
+
+    # The 'not node.prompt' case only hits in show-all mode, for promptless
+    # symbols and choices
+    return not node.prompt or \
+           (_show_name and isinstance(node.item, (Symbol, Choice)))
+
+
+def _value_str(node):
+    # Returns the value part ("[*]", "<M>", "(foo)" etc.) of a menu node
+
+    item = node.item
+
+    if item in (MENU, COMMENT):
+        return ""
+
+    # Wouldn't normally happen, and generates a warning
+    if not item.orig_type:
+        return ""
+
+    if item.orig_type in (STRING, INT, HEX):
+        return "({})".format(item.str_value)
+
+    # BOOL or TRISTATE
+
+    if _is_y_mode_choice_sym(item):
+        return "(X)" if item.choice.selection is item else "( )"
+
+    tri_val_str = (" ", "M", "*")[item.tri_value]
+
+    if len(item.assignable) <= 1:
+        # Pinned to a single value
+        return "" if isinstance(item, Choice) else "-{}-".format(tri_val_str)
+
+    if item.type == BOOL:
+        return "[{}]".format(tri_val_str)
+
+    # item.type == TRISTATE
+    if item.assignable == (1, 2):
+        return "{{{}}}".format(tri_val_str)  # {M}/{*}
+    return "<{}>".format(tri_val_str)
+
+
+def _is_y_mode_choice_sym(item):
+    # The choice mode is an upper bound on the visibility of choice symbols, so
+    # we can check the choice symbols' own visibility to see if the choice is
+    # in y mode
+    return isinstance(item, Symbol) and item.choice and item.visibility == 2
+
+
+def _check_valid(sym, s):
+    # Returns True if the string 's' is a well-formed value for 'sym'.
+    # Otherwise, displays an error and returns False.
+
+    if sym.orig_type not in (INT, HEX):
+        return True  # Anything goes for non-int/hex symbols
+
+    base = 10 if sym.orig_type == INT else 16
+    try:
+        int(s, base)
+    except ValueError:
+        _error("'{}' is a malformed {} value"
+               .format(s, TYPE_TO_STR[sym.orig_type]))
+        return False
+
+    for low_sym, high_sym, cond in sym.ranges:
+        if expr_value(cond):
+            low_s = low_sym.str_value
+            high_s = high_sym.str_value
+
+            if not int(low_s, base) <= int(s, base) <= int(high_s, base):
+                _error("{} is outside the range {}-{}"
+                       .format(s, low_s, high_s))
+                return False
+
+            break
+
+    return True
+
+
+def _range_info(sym):
+    # Returns a string with information about the valid range for the symbol
+    # 'sym', or None if 'sym' doesn't have a range
+
+    if sym.orig_type in (INT, HEX):
+        for low, high, cond in sym.ranges:
+            if expr_value(cond):
+                return "Range: {}-{}".format(low.str_value, high.str_value)
+
+    return None
+
+
+def _is_num(name):
+    # Heuristic to see if a symbol name looks like a number, for nicer output
+    # when printing expressions. Things like 16 are actually symbol names, only
+    # they get their name as their value when the symbol is undefined.
+
+    try:
+        int(name)
+    except ValueError:
+        if not name.startswith(("0x", "0X")):
+            return False
+
+        try:
+            int(name, 16)
+        except ValueError:
+            return False
+
+    return True
+
+
+def _getch_compat(win):
+    # Uses get_wch() if available (Python 3.3+) and getch() otherwise.
+    #
+    # Also falls back on getch() if get_wch() raises curses.error, to work
+    # around an issue when resizing the terminal on at least macOS Catalina.
+    # See https://github.com/ulfalizer/Kconfiglib/issues/84.
+    #
+    # Also handles a PDCurses resizing quirk.
+
+    try:
+        c = win.get_wch()
+    except (AttributeError, curses.error):
+        c = win.getch()
+        if 0 <= c <= 255:
+            c = chr(c)
+
+    # Decent resizing behavior on PDCurses requires calling resize_term(0, 0)
+    # after receiving KEY_RESIZE, while ncurses (usually) handles terminal
+    # resizing automatically in get(_w)ch() (see the end of the
+    # resizeterm(3NCURSES) man page).
+    #
+    # resize_term(0, 0) reliably fails and does nothing on ncurses, so this
+    # hack gives ncurses/PDCurses compatibility for resizing. I don't know
+    # whether it would cause trouble for other implementations.
+    if c == curses.KEY_RESIZE:
+        try:
+            curses.resize_term(0, 0)
+        except curses.error:
+            pass
+
+    return c
+
+
+def _warn(*args):
+    # Temporarily returns from curses to shell mode and prints a warning to
+    # stderr. The warning would get lost in curses mode.
+    curses.endwin()
+    print("menuconfig warning: ", end="", file=sys.stderr)
+    print(*args, file=sys.stderr)
+    curses.doupdate()
+
+
+# Ignore exceptions from some functions that might fail, e.g. for small
+# windows. They usually do reasonable things anyway.
+
+
+def _safe_curs_set(visibility):
+    try:
+        curses.curs_set(visibility)
+    except curses.error:
+        pass
+
+
+def _safe_addstr(win, *args):
+    # Clip the line to avoid wrapping to the next line, which looks glitchy.
+    # addchstr() would do it for us, but it's not available in the 'curses'
+    # module.
+
+    attr = None
+    if isinstance(args[0], str):
+        y, x = win.getyx()
+        s = args[0]
+        if len(args) == 2:
+            attr = args[1]
+    else:
+        y, x, s = args[:3]
+        if len(args) == 4:
+            attr = args[3]
+
+    maxlen = _width(win) - x
+    s = s.expandtabs()
+
+    try:
+        # The 'curses' module uses wattr_set() internally if you pass 'attr',
+        # overwriting the background style, so setting 'attr' to 0 in the first
+        # case won't do the right thing
+        if attr is None:
+            win.addnstr(y, x, s, maxlen)
+        else:
+            win.addnstr(y, x, s, maxlen, attr)
+    except curses.error:
+        pass
+
+
+def _safe_addch(win, *args):
+    try:
+        win.addch(*args)
+    except curses.error:
+        pass
+
+
+def _safe_hline(win, *args):
+    try:
+        win.hline(*args)
+    except curses.error:
+        pass
+
+
+def _safe_vline(win, *args):
+    try:
+        win.vline(*args)
+    except curses.error:
+        pass
+
+
+def _safe_move(win, *args):
+    try:
+        win.move(*args)
+    except curses.error:
+        pass
+
+
+def _change_c_lc_ctype_to_utf8():
+    # See _CHANGE_C_LC_CTYPE_TO_UTF8
+
+    if _IS_WINDOWS:
+        # Windows rarely has issues here, and the PEP 538 implementation avoids
+        # changing the locale on it. None of the UTF-8 locales below were
+        # supported from some quick testing either. Play it safe.
+        return
+
+    def try_set_locale(loc):
+        try:
+            locale.setlocale(locale.LC_CTYPE, loc)
+            return True
+        except locale.Error:
+            return False
+
+    # Is LC_CTYPE set to the C locale?
+    if locale.setlocale(locale.LC_CTYPE) == "C":
+        # This list was taken from the PEP 538 implementation in the CPython
+        # code, in Python/pylifecycle.c
+        for loc in "C.UTF-8", "C.utf8", "UTF-8":
+            if try_set_locale(loc):
+                # LC_CTYPE successfully changed
+                return
+
+
+if __name__ == "__main__":
+    _main()
-- 
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