This shows how cycles can be made out of O-word subroutines or directly coded in Python.

# Assume G84.2 is remapped to Python g842 like so in the [RS274NGC] ini section:
# REMAP=G84.2 argspec=xyzqp python=g842 modalgroup=1
#
# then executing
#
#    G84.2 x1 y1 (line1)
#    x3 y3       (line2)
#    y5          (line3)
#    ...
#
#  will execute like:
#   *G84.2 x1 y1
#    G84.2 x3 y3
#    G84.2 x3 y5
#
# until motion is cleared with G80 or some other motion is executed.
#
# This enables writing cycles in Python, or as Oword procedures; in the
# latter case the self.motion_mode should be set in the Python epilog.
#

And the same thing as an Oword procedure:

# a cycle with an Oword sub
#REMAP=G84.3  modalgroup=1 argspec=xyzqp prolog=g843_prolog ngc=g843 epilog=g843_epilog


The examples only show they parameters they are fed, and dont do anything useful - "you get the idea".
Sticky parameters are handled properly.

Usage:

linuxcnc cycle.ini

hit run and see what happens.

To understand how things fit together:

- see the REMAP statements in cycle.ini
- python/remap.py contains the Python glue
- nc_subroutines/g843.ngc is an example 'cycle body'