Initial revision

diff --git a/Demo/scripts/eqfix.py b/Demo/scripts/eqfix.py
new file mode 100755 (executable)
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+++ b/Demo/scripts/eqfix.py
@@ -0,0 +1,168 @@
+#! /ufs/guido/bin/sgi/python
+#! /usr/local/python
+
+# Fix Python source files to use the new equality test operator,
+# i.e.,
+#      if x == y: ...
+# instead of
+#      if x = y: ...
+#
+# Command line arguments are files or directories to be processed.
+# Directories are searched recursively for files whose name looks
+# like a python module.
+# Symbolic links are always ignored (except as explicit directory
+# arguments).  Of course, the original file is kept as a back-up
+# (with a "~" attached to its name).
+#
+# Changes made are reported to stdout in a diff-like format.
+#
+# Undoubtedly you can do this using find and sed or perl, but this is
+# a nice example of Python code that recurses down a directory tree
+# and uses regular expressions.  Also note several subtleties like
+# preserving the file's mode and avoiding to even write a temp file
+# when no changes are needed for a file.
+#
+# NB: by changing only the function fixline() you can turn this
+# into a program for a different change to Python programs...
+
+import sys
+import regex
+import posix
+import path
+from stat import *
+
+err = sys.stderr.write
+dbg = err
+rep = sys.stdout.write
+
+def main():
+       bad = 0
+       if not sys.argv[1:]: # No arguments
+               err('usage: ' + argv[0] + ' file-or-directory ...\n')
+               sys.exit(2)
+       for arg in sys.argv[1:]:
+               if path.isdir(arg):
+                       if recursedown(arg): bad = 1
+               elif path.islink(arg):
+                       err(arg + ': will not process symbolic links\n')
+                       bad = 1
+               else:
+                       if fix(arg): bad = 1
+       sys.exit(bad)
+
+ispythonprog = regex.compile('^[a-zA-Z0-9_]+\.py$')
+def ispython(name):
+       return ispythonprog.match(name) >= 0
+
+def recursedown(dirname):
+       dbg('recursedown(' + `dirname` + ')\n')
+       bad = 0
+       try:
+               names = posix.listdir(dirname)
+       except posix.error, msg:
+               err(dirname + ': cannot list directory: ' + `msg` + '\n')
+               return 1
+       names.sort()
+       subdirs = []
+       for name in names:
+               if name in ('.', '..'): continue
+               fullname = path.join(dirname, name)
+               if path.islink(fullname): pass
+               elif path.isdir(fullname):
+                       subdirs.append(fullname)
+               elif ispython(name):
+                       if fix(fullname): bad = 1
+       for fullname in subdirs:
+               if recursedown(fullname): bad = 1
+       return bad
+
+def fix(filename):
+       dbg('fix(' + `filename` + ')\n')
+       try:
+               f = open(filename, 'r')
+       except IOError, msg:
+               err(filename + ': cannot open: ' + `msg` + '\n')
+               return 1
+       head, tail = path.split(filename)
+       tempname = path.join(head, '@' + tail)
+       g = None
+       # If we find a match, we rewind the file and start over but
+       # now copy everything to a temp file.
+       lineno = 0
+       while 1:
+               line = f.readline()
+               if not line: break
+               lineno = lineno + 1
+               while line[-2:] == '\\\n':
+                       nextline = f.readline()
+                       if not nextline: break
+                       line = line + nextline
+                       lineno = lineno + 1
+               newline = fixline(line)
+               if newline != line:
+                       if g is None:
+                               try:
+                                       g = open(tempname, 'w')
+                               except IOError, msg:
+                                       f.close()
+                                       err(tempname+': cannot create: '+\
+                                           `msg`+'\n')
+                                       return 1
+                               f.seek(0)
+                               lineno = 0
+                               rep(filename + ':\n')
+                               continue # restart from the beginning
+                       rep(`lineno` + '\n')
+                       rep('< ' + line)
+                       rep('> ' + newline)
+               if g is not None:
+                       g.write(newline)
+
+       # End of file
+       f.close()
+       if not g: return 0 # No changes
+       
+       # Finishing touch -- move files
+
+       # First copy the file's mode to the temp file
+       try:
+               statbuf = posix.stat(filename)
+               posix.chmod(tempname, statbuf[ST_MODE] & 07777)
+       except posix.error, msg:
+               err(tempname + ': warning: chmod failed (' + `msg` + ')\n')
+       # Then make a backup of the original file as filename~
+       try:
+               posix.rename(filename, filename + '~')
+       except posix.error, msg:
+               err(filename + ': warning: backup failed (' + `msg` + ')\n')
+       # Now move the temp file to the original file
+       try:
+               posix.rename(tempname, filename)
+       except posix.error, msg:
+               err(filename + ': rename failed (' + `msg` + ')\n')
+               return 1
+       # Return succes
+       return 0
+
+PAT1 = '\<\(if\|elif\|while\)\>[\0-\377]*[^<>!=]\(=\)[^=][\0-\377]*[^[]:[^]]'
+#         \2                                    \3
+PAT2 = '\<return\>[\0-\377]*[^<>!=]\(=\)[^=]'
+#                                  \4
+PAT = '^[ \t]*\(' + PAT1 + '\|' + PAT2 + '\)'
+#             \1
+prog = regex.compile(PAT)
+
+def fixline(line):
+       while prog.match(line) >= 0:
+               regs = prog.regs
+               if regs[3] == (-1, -1):
+                       a, b = regs[4]
+               else:
+                       a, b = regs[3]
+               if not 0 < a < b < len(line):
+                       dbg('Weird: ' + line)
+                       break
+               line = line[:a] + '==' + line[b:]
+       return line
+
+main()