Python script to embed min/max XY movements into gcode

#!/usr/bin/python
import sys
import re
import os

parmNotes = ''

sourceFile=sys.argv[1]
destFile=sourceFile

# Read the ENTIRE g-code file into memory
with open(sourceFile, "r") as f:
    lines = f.readlines()

    # print position variables
    coordMinX = 9999.9
    coordMaxX =0.0
    coordMinY = 9999.9
    coordMaxY = 0.0

    currLine = 1
    parsing = False # extruder position parsing flag

for line in lines:
    currLine += 1
    parts = line.split(';', 1)
    if len(parts) > 0:
        # Parse command
        command = parts[0].strip()
        if len(parts) > 1:
            # Parse comments
            comment = parts[1].strip()

        # Track extruder movement ranges
        # Note that this requires enabling verbose logging in Slic3r (output options)
        if not re.search(";", comment):
            # Limit tracking to print movements, avoid start and end gcode blocks
            if re.search("move to first skirt point", comment):
                #if not parsing:
                #    print("Start extruder movement parsing at line %d with %s" % (currLine, comment))
                parsing = True
            if re.search("PURGING FINISHED", comment):
                #print("Stop extruder movement parsing at line %d with %s" % (currLine, comment))
                parsing = False
        if parsing:
            stringMatch = re.search ('^G[01].*X([0-9.]+)', command)
            if stringMatch:
                # extract x-axis moves
                val = float(stringMatch.group(1))
                # print("%s: X is %d" % (currLine, val))
                if(val < coordMinX):
                    coordMinX = val
                if(val > coordMaxX):
                    coordMaxX = val
            stringMatch = re.search ('^G[01].*Y([0-9.]+)', command)
            if stringMatch:
                # extract y-axis moves
                val = float(stringMatch.group(1))
                if(val < coordMinY):
                    coordMinY = val
                if(val > coordMaxY):
                    coordMaxY = val

os.rename(sourceFile,destFile+".xyminmax.bak")
destFile = re.sub('\.gcode$','',sourceFile)
destFile = destFile + '.gcode'

with open(destFile, "w") as of:
    of.write('; Minimum X = '+ str(coordMinX)+'\n')
    of.write('; Maximum X = '+ str(coordMaxX)+'\n')
    of.write('; Minimum Y = '+ str(coordMinY)+'\n')
    of.write('; Maximum Y = '+ str(coordMaxY)+'\n')
    for lIndex in xrange(len(lines)):
        oline = lines[lIndex]
        of.write(oline)

of.close()
f.close()