Rudimentary Calcomp to HPGL converter

calcomp_to_hpgl.py

#!/usr/bin/python3
# Copyright 2024 Google LLC.
# SPDX-License-Identifier: Apache-2.0
# Extremely limited Calcomp plotter language to HPGL converter, targeting
# specifically files output by code at
# https://gitlab.com/metagrowing/VZ.AND..NOT.VT.OR..NOT.VZ.AND.VT

from sys import stdin, stdout
from math import pi

stdout.write('IN;PU;SP1')
pen_up = False

xfix = lambda x_str: max(int(2e4*float(x_str) / 8 / pi), 0)
yfix = lambda y_str: max(1e4 - int(2e4*float(y_str) / 8 / pi), 0)

for line in stdin:
  match line.strip().lower().split():
    case ['plot', x_str, y_str, '2']:
      stdout.write(f'{";PD" if pen_up else ","}{yfix(y_str)},{xfix(x_str)}')
      pen_up = False
    case ['plot', x_str, y_str, '3']:
      stdout.write(f'{"," if pen_up else ";PU"}{yfix(y_str)},{xfix(x_str)}')
      pen_up = True
    case ['plot', x_str, y_str, '999']:
      stdout.write(';IN;')  # All done

NB: "Calcomp plotter language" here means the FORTRAN subroutine calls that would command the plotter to draw etc.
Here's a reference for Calcomp's FORTRAN API.