M is both an argument and a command

[Michael-F-Bryan]

There are several letters which can be both commands and arguments, depending on the context. It might be necessary to refactor the parser to take into account things like newline characters and what the last command was.

Here's an exerpt from an automatically generated program my roommate gave me.

;FLAVOR:RepRap
;TIME:5373
;Filament used: 3.18051m
;Layer height: 0.1
;Generated with Cura_SteamEngine 2.4.0
M190 S90
M104 S235
M109 S235
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops

But when you put it through the parser, the M190 and other M commands get parsed as arguments instead of commands.

M190 S90 M104 S235 M109 S235    (line: 5, column: 1)
G21     (line: 8, column: 1)
G90 M82 M107    (line: 9, column: 1)
G28 X0 Y0       (line: 12, column: 1)
G28 Z0  (line: 13, column: 1)
G1 Z15 F9000    (line: 14, column: 1)
G92 E0  (line: 15, column: 1)
G1 F200 E3      (line: 16, column: 1)
G92 E0  (line: 17, column: 1)
G1 F9000 M117   (line: 18, column: 1)

[Michael-F-Bryan]

Turns out an M code and a G code cannot be combined in a single instruction. So this should just be a case of removing M from the arg_kind rule in the grammar.

[brainlag]

Isn't M not always a command?
When you have code like this:

G01 Y30 M8

then doesn't it basically mean:

M8
G01 Y30

[Michael-F-Bryan]

Ah, originally I thought M could be an argument to a T command.

E.g.:

T01 M06

But turns out that's just preparing to change to tool 1 then calling M06 to actually swap tools. So it's two instructions put on the same line.

I think we used a machine-specific G code for changing tools when I did a unit on CNC and other machining processes, which may explain why I didn't pick this up.

[benmkw]

I currently have a command like M0 Turn ON 5000RPM in gcode which I'm not sure how to handle correctly using this parser.