RE: [Pyparsing] RE: Pyparsing unicode

[Paul M. <pa...@al...>]

> -----Original Message-----
> From: Jean-Paul Calderone [mailto:ex...@di...] 
> Sent: Saturday, May 13, 2006 1:37 PM
> To: Paul McGuire
> Cc: pyp...@li...
> Subject: Re: [Pyparsing] RE: Pyparsing unicode
> 
<snip>
> 
> I took your lead and produced the attached stand-alone test 
> based on a couple actions in Imaginary.  It includes a 
> slightly different version of targetString (one that uses 
> removeQuotes) and shows two different failures.  Any insights 
> you have would be appreciated.
> 
> Jean-Paul
> 

Great test case!

Ok, here is the problem:  in 1.4.2, I expanded the concept of parse actions
to support a list of parse actions, to be executed in a chain, instead of
just one.  Every call to setParseAction *adds* the current action to the
expression's list of parse actions (yes, I see that this is *not* intuitive,
and I will fix this!  Instead of expanding the behavior of setParseAction, I
should have added a new method, something like addParseAction, or something
that clearly implies that we are adding the current parse action to whatever
other actions have already been defined).  Because you are calling
setParseAction on the global quotedString, the results get pared back again
and again.  I might also adjust removeQuotes to only remove the first and
last characters if they are in fact quote characters - I'm not sure about
this yet, though.

Here are 2 possible workarounds for you:

1. use a copy of quotedString in your definition of qstr inside
targetString.  Change:
    qstr = pyparsing.quotedString.setParseAction(pyparsing.removeQuotes)
To:
    qstr =
pyparsing.quotedString.copy().setParseAction(pyparsing.removeQuotes)

2. Take care to only attach removeQuotes to quotedString *once*, perhaps
right after calling import.
import pyparsing
pyparsing.quotedString.setParseAction(pyparsing.removeQuotes)
Then inside targetString, just assign qstr as:
    qstr = pyparsing.quotedString

Sorry for the confusion!  Let me know what you settle on doing.

-- Paul