docs: Updates for gcode_macro naming (#2317)

Add note about numbers in macro names.  Add note about variable name case restriction. Add set variable example.

Signed-off-by: David O Smith <davidosmith@gmail.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index 36e6beb7..9c815813 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -389,7 +389,9 @@
 ######################################################################
 
 # G-Code macros (one may define any number of sections with a
-# "gcode_macro" prefix).
+# "gcode_macro" prefix). If G-Code macro names contain any numbers
+# they must all be at the end of the macro's name.
+# (example: test_macro25 is acceptable, but macro25_test3 is not).
 #[gcode_macro my_cmd]
 #gcode:
 #   A list of G-Code commands to execute in place of "my_cmd". See
@@ -409,9 +411,13 @@
 #   One may specify any number of options with a "variable_" prefix.
 #   The given variable name will be assigned the given value (parsed
 #   as a Python literal) and will be available during macro expansion.
-#   For example, a config with "variable_fan_speed = 75" might have
-#   gcode commands containing "M106 S{ fan_speed * 255 }". Variables
-#   can be changed at run-time using the SET_GCODE_VARIABLE command.
+#   For example, a macro called set_fan with
+#   "variable_fan_speed = 75" might have gcode commands containing
+#   "M106 S{ fan_speed * 255 }". Variables can be changed at run-time
+#   using the SET_GCODE_VARIABLE command from within any G-Code Macro.
+#   Example, from a macro called my_macro2 I could state:
+#   "SET_GCODE_VARIABLE MACRO=set_fan VARIABLE=fan_speed VALUE=50"
+#   Variable names may not use upper case characters.
 
 # Execute a gcode on a set delay.
 #[delayed_gcode my_delayed_gcode]