1  #! /usr/bin/env python3
       2  # This script generates Modules/_sre/sre_constants.h from Lib/re/_constants.py.
       3  
       4  
       5  def update_file(file, content):
       6      try:
       7          with open(file, 'r') as fobj:
       8              if fobj.read() == content:
       9                  return False
      10      except (OSError, ValueError):
      11          pass
      12      with open(file, 'w') as fobj:
      13          fobj.write(content)
      14      return True
      15  
      16  sre_constants_header = """\
      17  /*
      18   * Secret Labs' Regular Expression Engine
      19   *
      20   * regular expression matching engine
      21   *
      22   * Auto-generated by Tools/scripts/generate_sre_constants.py from
      23   * Lib/re/_constants.py.
      24   *
      25   * Copyright (c) 1997-2001 by Secret Labs AB.  All rights reserved.
      26   *
      27   * See the sre.c file for information on usage and redistribution.
      28   */
      29  
      30  """
      31  
      32  def main(
      33      infile="Lib/re/_constants.py",
      34      outfile_constants="Modules/_sre/sre_constants.h",
      35      outfile_targets="Modules/_sre/sre_targets.h",
      36  ):
      37      ns = {}
      38      with open(infile) as fp:
      39          code = fp.read()
      40      exec(code, ns)
      41  
      42      def dump(d, prefix):
      43          items = sorted(d)
      44          for item in items:
      45              yield "#define %s_%s %d\n" % (prefix, item, item)
      46  
      47      def dump2(d, prefix):
      48          items = [(value, name) for name, value in d.items()
      49                   if name.startswith(prefix)]
      50          for value, name in sorted(items):
      51              yield "#define %s %d\n" % (name, value)
      52  
      53      def dump_gotos(d, prefix):
      54          for i, item in enumerate(sorted(d)):
      55              assert i == item
      56              yield f"    &&{prefix}_{item},\n"
      57  
      58      content = [sre_constants_header]
      59      content.append("#define SRE_MAGIC %d\n" % ns["MAGIC"])
      60      content.extend(dump(ns["OPCODES"], "SRE_OP"))
      61      content.extend(dump(ns["ATCODES"], "SRE"))
      62      content.extend(dump(ns["CHCODES"], "SRE"))
      63      content.extend(dump2(ns, "SRE_FLAG_"))
      64      content.extend(dump2(ns, "SRE_INFO_"))
      65  
      66      update_file(outfile_constants, ''.join(content))
      67  
      68      content = [sre_constants_header]
      69      content.append(f"static void *sre_targets[{len(ns['OPCODES'])}] = {{\n")
      70      content.extend(dump_gotos(ns["OPCODES"], "TARGET_SRE_OP"))
      71      content.append("};\n")
      72  
      73      update_file(outfile_targets, ''.join(content))
      74  
      75  
      76  if __name__ == '__main__':
      77      import sys
      78      main(*sys.argv[1:])