Re: [Pyparsing] keepOriginalText problem

[Stefaan H. <ste...@gm...>]

Hello Paul, and thank you for the swift reply!

Because this problem was rather urgent I had already reworked the grammar to
avoid using keepOriginalText,
and that solved the problem in my case (but I also had to modify the client
program that uses the parser...)

Your alternative to keepOriginalText looks interesting, and I will keep it
in mind to play with the next time I am trying to
parse something using pyparsing (which is quite often these days ;) )

Best regards, and thanks again,
Stefaan.

On Thu, Jul 3, 2008 at 2:58 PM, Paul McGuire <pt...@au...> wrote:

> Stefaan -
>
> I suspect the problem is with the inspect module usage, don't know how to
> work around that per se.
>
> However, I did come up with something interesting.  I defined an Empty()
> with a parse action that just returns the current parse location.  I then
> bracketed your remove_lines expression with one of these at the beginning
> and at the end, with appropriate results names.  Then instead of attaching
> keepOriginalText, I attached a simple lambda that returns the slice of the
> input string from the given begin and end values.  See below:
>
> # a dummy expression that just returns the current parse location
> get_cur_locn = p.Empty().setParseAction(lambda s,l,t: l)
>
> remove_line = p.lineStart + p.Literal("<").suppress() + \
>    p.restOfLine.setResultsName("LineContents") + p.lineEnd
>
> # put get_cur_locn exprs at front and back of remove_lines, with
> # useful results names - (Combine is not really necessary, I don't think)
> remove_lines = get_cur_locn("begin") + \
>    p.OneOrMore(remove_line) + \
>    get_cur_locn("end")
>
> # now replace keepOriginalText with simple string slice - should be
> # faster, too!
> remove_lines.setParseAction(lambda s,l,t:s[t.begin:t.end])
>
>
> HTH,
> -- Paul
>
>
>
> -----Original Message-----
> From: pyp...@li...
> [mailto:pyp...@li...] On Behalf Of
> stefaan
> Sent: Thursday, July 03, 2008 6:20 AM
> To: pyp...@li...
> Subject: [Pyparsing] keepOriginalText problem
>
> Hello,
>
> I have a problem with keepOriginalText: when I try to parse a grammar using
> the
> keepOriginalText parse action inside a cherrypy 2.2.1-based web
> application,
> the
> getTokensEndLoc() fails and I get a traceback:
>
> File "C:\shi\webapp\comparefiles\comparefiles.py", line 273, in doCompare
>    NormalDiffParser.remove_lines.parseString("< line 1" + os.linesep + "<
> line
> 2" + os.linesep)
>  File "C:\shi\webapp\comparefiles\diffparser\pyparsing.py", line 981, in
> parseString
>    loc, tokens = self._parse( instring, 0 )
>  File "C:\shi\webapp\comparefiles\diffparser\pyparsing.py", line 886, in
> _parseNoCache
>    tokens = fn( instring, tokensStart, retTokens )
>  File "C:\shi\webapp\comparefiles\diffparser\pyparsing.py", line 3156, in
> keepOriginalText
>    endloc = getTokensEndLoc()
>  File "C:\shi\webapp\comparefiles\diffparser\pyparsing.py", line 3167, in
> getTokensEndLoc
>    fstack = inspect.stack()
>  File "D:\Python24\lib\inspect.py", line 819, in stack
>    return getouterframes(sys._getframe(1), context)
>  File "D:\Python24\lib\inspect.py", line 800, in getouterframes
>    framelist.append((frame,) + getframeinfo(frame, context))
>  File "D:\Python24\lib\inspect.py", line 769, in getframeinfo
>    raise TypeError('arg is not a frame or traceback object')
> TypeError: arg is not a frame or traceback object
>
> The grammar for remove_lines:
>
> import pyparsing as
> remove_line = p.lineStart + p.Literal("<").suppress() + \
> p.restOfLine.setResultsName("LineContents") + p.lineEnd
> remove_lines = p.Combine(p.OneOrMore(remove_line))
> remove_lines.setParseAction(p.keepOriginalText)
>
>
> The same program, with the same input, works flawlessly in a "normal" (i.e.
> not
> webapplication) script.
>
>
>
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