python/preppy

#!/usr/bin/env python
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#

import os, re, sys

ann = re.compile(r"([ \t]*)@([_a-zA-Z][_a-zA-Z0-9]*)([ \t\n\r]+def[ \t]+)([_a-zA-Z][_a-zA-Z0-9]*)")
line = re.compile(r"\n([ \t]*)[^ \t\n#]+")

if len(sys.argv) == 2:
  major, minor = [int(p) for p in sys.argv[1].split(".")]
elif len(sys.argv) == 1:
  major, minor = sys.version_info[0:2]
else:
  print "usage: %s [ version ] < input.py > output.py" % sys.argv[0]
  sys.exit(-1)

if major <= 2 and minor <= 3:
  def process(input):
    output = ""
    pos = 0
    while True:
      m = ann.search(input, pos)
      if m:
        indent, decorator, idef, function = m.groups()
        output += input[pos:m.start()]
        output += "%s#@%s%s%s" % (indent, decorator, idef, function)
        pos = m.end()

        subst = "\n%s%s = %s(%s)\n" % (indent, function, decorator, function)
        npos = pos
        while True:
          n = line.search(input, npos)
          if not n:
            input += subst
            break
          if len(n.group(1)) <= len(indent):
            idx = n.start()
            input = input[:idx] + subst + input[idx:]
            break
          npos = n.end()
      else:
        break

    output += input[pos:]
    return output
else:
  def process(input):
    return input

sys.stdout.write(process(sys.stdin.read()))