Adding support for additional XYZ axes
Extending the number of supported axes is limited by the alphabet. Some controls get round this limit by appending a back tick to the axis word.
Using a Bison type parser, this sort of extension is easy to incorporate at the lexing stage. Just need code at the lower levels to handle it. Using an F word to specify angular feed rates separate to linear feed rates also becomes a practical proposition.
` N3200 G1 X5 Y-2.4 F150 A45 F’360 ` becomes a possibility. Although handling moves that complete at different times is still problematic. Another area where back tick words could be used is with G03 U4 V3 W7 R'5 to provide circular interpolation with UVW. Possibly extend this with G'17 so that XYZ and UVW can interpolate circular moves in different planes.
All very non-standard, but it does demonstrate how easy it is to add new features when using a BNF parser as long as the rest of the code base is equally flexible.