Re: [Pyparsing] recursion in _flatten after version 1.5.2

[Paul M. <pt...@au...>]

Luke -

I tripped over this same bug doing HTML tag stripping.  The latest pyparsing
in SVN has a version of _flatten that uses a lot less recursion. Also, a
slightly improved version of transformString, which is smart enough to leave
out empty strings from the list of strings to be joined.

The new _flatten only recurses if there is a nesting of parsed structures:

def _flatten(L):
    ret = []
    for i in L:
        if isinstance(i,list):
            ret.extend(_flatten(i))
        else:
            ret.append(i)
    return ret

-- Paul


-----Original Message-----
From: Luke Campagnola [mailto:lca...@em...] 
Sent: Monday, May 30, 2011 10:28 AM
To: pyp...@li...
Subject: [Pyparsing] recursion in _flatten after version 1.5.2

Howdy,
I have a script that I use to strip comments from C files. The code fails
for any pyparsing version later than 1.5.2.
Backtrace looks like this:

    File "CParser.py", line 300, in removeComments
      self.files[file] = (quotedString | cStyleComment.suppress() |
cplusplusLineComment.suppress()).transformString(text)
    File "c:\python27\lib\site-packages\pyparsing.py", line 1166, in
transformString
      return "".join(map(_ustr,_flatten(out)))
    File "c:\python27\lib\site-packages\pyparsing.py", line 3190, in
_flatten
      return _flatten(L[0]) + _flatten(L[1:])
    File "c:\python27\lib\site-packages\pyparsing.py", line 3190, in
_flatten
      return _flatten(L[0]) + _flatten(L[1:])
    . . .
    File "c:\python27\lib\site-packages\pyparsing.py", line 3188, in
_flatten
      if type(L) is not list: return [L]
  RuntimeError: maximum recursion depth exceeded while calling a Python
object


If I remember correctly, 'quotedString' and cStyleComment' are provided by
pyparsing, and I have provided this definition:

    cplusplusLineComment = Literal("//") + restOfLine

Any hints?

Luke
----------------------------------------------------------------------------
--
vRanger cuts backup time in half-while increasing security.
With the market-leading solution for virtual backup and recovery, 
you get blazing-fast, flexible, and affordable data protection.
Download your free trial now. 
http://p.sf.net/sfu/quest-d2dcopy1
_______________________________________________
Pyparsing-users mailing list
Pyp...@li...
https://lists.sourceforge.net/lists/listinfo/pyparsing-users