gron in Python

gron.py

#!/usr/bin/python3 -SB

import re
import sys
import json

def main():
    o = json.loads(sys.stdin.read())
    gron(["json"], o)

def gron(path, o):
    if isinstance(o, dict):
        print("%s = {};" % format_path(path))
        for k in sorted(o):
            gron(path + [k], o[k])
    elif isinstance(o, list):
        print("%s = [];" % format_path(path))
        for n, v in enumerate(o):
            gron(path + [n], v)
    else:
        print("%s = %s;" % (format_path(path), json.dumps(o)))

def format_path(path):
    out = ""
    for n, seg in enumerate(path):
        if can_leave_unquoted(seg):
            dot = "." if n else ""
            out += "%s%s" % (dot, seg)
        else:
            out += "[%s]" % json.dumps(seg)
    return out

identifier_re = re.compile(r"\A[_$A-Za-z][_$A-Za-z0-9]*\Z")
reserved_words = set("""
    break case catch class const continue debugger default delete do else export
    extends false finally for function if import in instanceof new null return
    super switch this throw true try typeof var void while with yield
    """.split())

def can_leave_unquoted(key):
    if isinstance(key, int):
        return False
    elif key in reserved_words:
        return False
    elif re.match(identifier_re, key):
        return True
    else:
        return False

if __name__ == "__main__":
    main()

Moved to https://github.com/ludios/quickmunge/blob/master/bin/gron