Re: [Pyparsing] pyparsing svg - noob

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

You are right, parseString really returns an object, ParseResults.
ParseResults tries to behave much like a list, but adds some dict-like and
object-like behavior too.  I see I overlooked pop() in ParseResults'
methods, I'll try to remember to include that in the next version.  (You may
have to resort to reading some documentation soon...)

If you really, really, really want to pop your way through the tokens, you
can convert the results to a list by using asList(), and then pop() away!

I forgot to mention in the other e-mail:

Another recommended technique is to do conversions like string-to-float
during the parsing process itself, by adding a parse action.  Let's assume
you changed the variable name float to floatNum:

floatNum = Combine(Optional("-") + Word(nums) + dot + Word(nums))

Now add:
def convertToFloat(tokens):
    return float(tokens[0])
floatNum.setParseAction(convertToFloat)

Or if you want to make this a one-liner (more compact, but a lot to take in
at once when first learning):

floatNum.setParseAction(lambda toks:float(toks[0]))

Now when you process the resulting tokens, the floats will already be
floating point numbers instead of strings, no need to convert them
after-the-fact.

-- Paul



-----Original Message-----
From: pyp...@li...
[mailto:pyp...@li...] On Behalf Of Donn
Sent: Thursday, November 08, 2007 5:39 AM
To: Paul McGuire
Cc: pyp...@li...
Subject: Re: [Pyparsing] pyparsing svg - noob

Paul,
Sorry to bug you. Two things: 
1. I am having a conceptual issue with the "list" returned by parseString. I

can't seem to use it as a normal list. Mainly I like to while len(l)>0: and 
then l.pop(0) to process it but I can't seem to pop this list.
2. It seems the optional closing "Z" is being ignored.

dot = Literal(".")
float = Combine(Optional("-") + Word(nums) + dot + Word(nums))
command = oneOf("M L C Z")
comma = Literal(",").suppress()
couple = Group(float + comma + float)
phrase = OneOrMore(command + Group(OneOrMore(couple)) )

#No C commands in this one...
d1="""M 209.12237,172.2415 L 286.76739,153.51369 L 286.76739,275.88534 L 
209.12237,294.45058 L 209.12237,172.2415 z """

paths = []
pl = phrase.parseString(d1.upper())

while len(pl) > 0:
 something = pl.pop(0)
 print something

(I get : TypeError: 'str' object is not callable)

I could use <for something in pl:> but since some of the coord lists are 
longer than others and not grouped ideally, it gets hairy. 

The ideal grouping would be something like this (I mix C and L commands)
['M', [float,float],
'C',[float,float,float,float,float,float],
'L',[float,float],
'Z']
So I can just pop them off one by one.

\d

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