There are a lot of repetitive aspects to writing gcodes.
Applets have been written to automate specific coding tasks.
Try out some of the ones below. Full Source is included, naturally.

Bore a hole with a mill. Specify CW/CCW, origin, inside diameter, starting degress, depth, stepover, stepdown, finish cut.
DEMO PAGE
DOWNLOAD

Note- some demos are not done, some of these applets aren't good enuff to post yet, and the ones which are posted are free, with all the responsibility that implies for me = NONE.

Bore arcs with a mill. Specify CW/CCW, origin, inside diameter, starting degress, arc degrees and finish cut.
Bolt circles. Specify # eq.sp. points, origin, starting degrees, travel by arc/line and code to paste for each point.
Bore posts with a mill. Specify CW/CCW, origin, outside diameter, starting degress, arc degrees and finish cut.
I have a bunch of little utilities in the works, as well as a 'GLUI' which is an app i made that lets me put all the little applets together as if they were a suite of tools - you can add your own stuff to it easily. They will appear as i have time - i have much to do and documentation/help files are not near top of the list, sorry...
Clean up a CNC file. Remove line #s, spaces, blank lines, and comments.
Reverse a toolpath on the clipboard (it doesn't do arcs right!! dumb string invert.)