[Solved] "Bad character '-'" (and '+') in G-code. Program won't load.

andypugh wrote:

clunc wrote: G-code AIN'T algerber:

Though it is quite close to Gerber

There's a reason for that. G-code is officially RS-274D. Gerber files are a form of RS-274 with suppressed decimal points.
The original Gerber photoplotter used a GE CNC control, and the tool changer selected an aperture on a wheel.
Then, it did modal moves, and the modal command in effect selected between dark move, light on when moving or flash at that location. So, all very standard G-code stuff.

Jon