pyparsing-users — User notes and help on the pyparsing module

[Pyparsing] [Fwd: 1. .suppress() does not work; 2. a new API call suggestion]

[Victor P. <po...@na...>]

Probably it is a bug in pyparsing, but most probably is my
misunderstanding.

Note that it uses modified pyparsing with new method .addCondition()
(attached).

When I run my script (attached):

$ ./DuplicateRefs.py chap-filt.lyx

it produces output like:

['name "chap-filt"']

In my opinion, it should instead produce

['chap-filt']

because I use .suppress() in my code.

Sorry, that I package the data in a separate file, not in a string, but
the real example file is long.

What is wrong? How to make it to produce only label name (like 'chap
-filt'), not like ['name "chap-filt"']?

Additional issue:

Because of peculiarity of the syntax of the .lyx file (attached) I
analyze, I first split it into tokens and then parse the tokens
themselves (with another parser). See for example:

LabelNameLineParser = \
    pyparsing.Keyword("name").suppress() + pyparsing.White("
").suppress() + \
        pyparsing.Literal('"').suppress() + pyparsing.CharsNotIn('"') +
pyparsing.Literal('"').suppress()

LabelNameLine = Line.copy().addCondition(lambda self, loc, toks:
LabelNameLineParser.parseString(toks[0], True))

Maybe, we should introduce a shorter API for tasks like this? (I am
unsure whether this situation is often enough to deserve a special
API.) What is your opinion? What if I will write a patch which does
this? will you use it?

-- 
Victor Porton - http://portonvictor.org

[Pyparsing] Using pyparsing to parse and convert algebraic expressions

[Alexander B. <ale...@gm...>]

Hi all,

I try to use pyparsing to parse mathematics expressions with functions and
variables and convert this expression in different notation. Also
during conversion
variables should be replaced with corresponding path using
substitution dictionary.
For example, input expression

var1 + var2

should be transformer into

binarymath(/path/to/file1, /path/to/file2, substract)

Here is a bit more complex example

var1 / sin(var2) + var3

should be transformed into

binarymath(binarymath(/path/to/file1, sin(/path/to/file2), divide),
/path/to/file3, add)

I looked over examples and decided to use fourfn.py as base for my parser. To
distinguish variables from functions I decide to include variables into double
quotes e.g. "var1" + log10("var2").  After some investigating I come with next
code

import re
from pyparsing import (Literal, CaselessLiteral, Word, Group, Combine, Optional,
    ZeroOrMore, Forward, nums, alphas, Regex, ParseException)

exprStack = []
rasters = dict()

def pushFirst(strg, loc, toks):
    exprStack.append(toks[0])

def pushUMinus(strg, loc, toks):
    for t in toks:
        if t == '-':
            exprStack.append('unary -')
        else:
            break

def rasterPath(rasterName):
    global rasters
    return rasters[rasterName]

# Define grammar
bnf = None

def BNF():
    global bnf
    if not bnf:
        point = Literal('.')
        colon = Literal(',')
        e = CaselessLiteral('E')
        pi = CaselessLiteral( "PI" )
        fnumber = Regex(r'[+-]?\d+(:?\.\d*)?(:?[eE][+-]?\d+)?')
        ident = Combine('"' + Word(alphas, alphas + nums + '_') + '"')
        func = Word(alphas)
        plus = Literal('+')
        minus = Literal('-')
        mult = Literal('*')
        div = Literal('/')
        mod = Literal('%')
        lpar = Literal('(').suppress()
        rpar = Literal(')').suppress()
        addop = plus | minus
        multop = mult | div | mod
        expop = Literal('^')

        expr = Forward()
        atom = ((0, None) * minus + (pi | e | fnumber | ident | func +
lpar + expr + rpar | ident).setParseAction(pushFirst) |
                Group(lpar + expr + rpar)).setParseAction(pushUMinus)

        # by defining exponentiation as "atom [ ^ factor ]..." instead of
        # "atom [ ^ atom ]...", we get right-to-left exponents, instead of
        # left-to-righ that is, 2^3^2 = 2^(3^2), not (2^3)^2.
        factor = Forward()
        factor << atom + ZeroOrMore((expop + factor).setParseAction(pushFirst))

        term = factor + ZeroOrMore((multop + factor).setParseAction(pushFirst))
        expr << term + ZeroOrMore((addop + term).setParseAction(pushFirst))
        bnf = expr
    return bnf

# map operator symbols to corresponding arithmetic operations
opn = {'+': lambda x, y: 'binarymathraster({}, {}, add)'.format(x, y),
       '-': lambda x, y: 'binarymathraster({}, {}, substract)'.format(x, y),
       '*': lambda x, y: 'binarymathraster({}, {}, times)'.format(x, y),
       '/': lambda x, y: 'binarymathraster({}, {}, divide)'.format(x, y),
       '%': lambda x, y: 'binarymathraster({}, {}, mod)'.format(x, y),
       '^': lambda x, y: 'binarymathraster({}, {}, power)'.format(x, y)}

fn  = {'sin': lambda x: 'sin({})'.format(x),
       'cos': lambda x: 'cos({})'.format(x),
       'tan': lambda x: 'tan({})'.format(x),
       'asin': lambda x: 'asin({})'.format(x),
       'acos': lambda x: 'acos({})'.format(x),
       'atan': lambda x: 'atan({})'.format(x),
       'log10': lambda x: 'log10({})'.format(x),
       'ln': lambda x: 'ln({})'.format(x),
       'abs': lambda x: 'abs({})'.format(x),
       'sqrt': lambda x: 'sqrt({})'.format(x),
       'ceil': lambda x: 'ceil({})'.format(x),
       'floor': lambda x: 'floor({})'.format(x),
       'sign': lambda x: 'sign({})'.format(x),
       'sinh': lambda x: 'sinh({})'.format(x)}

def evaluateStack(s):
    op = s.pop()
    if op == 'unary -':
        return -evaluateStack(s)
    if op in '+-*/^':
        op2 = evaluateStack(s)
        op1 = evaluateStack(s)
        return opn[op](op1, op2)
    elif op == 'PI':
        return math.pi # 3.1415926535
    elif op == 'E':
        return math.e  # 2.718281828
    elif op in fn:
        return fn[op](evaluateStack(s))
    elif re.search('\"(.+?)\"', op):
        return rasterPath(op.strip('"'))
    elif op[0].isalpha():
        raise Exception('invalid identifier "%s"' % op)
    else:
        return float(op)

Here is same code at pastibin http://pastebin.com/McQzfg2d.

Is this correct approach? As I'm new to pyparsing I would be very thankful for
feedback and suggestions how to improve this code and make it reliable and
easy to extend with new functions/operators.

Thanks and sorry for my English
-- 
Alexander Bruy

Re: [Pyparsing] Difference between Mac and Windows?

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

Please check what version of pyparsing you are running. I think your Mac has
an older version installed.

Python
>>> import pyparsing
>>> pyparsing.__version__

Should print 2.0.3

This latest version expands arrays of objects - older versions did not.

To get the latest version of pyparsing, use easy_install or pip.

-- Paul


-----Original Message-----
From: mlist @dslextreme.com [mailto:ml...@ds...] 
Sent: Wednesday, April 22, 2015 12:34 PM
To: pyp...@li...
Subject: [Pyparsing] Difference between Mac and Windows?

I am seeing something strange. At first, I thought I was doing something
wrong, but now I wonder if it is a bug.  I have my script (Dropbox
<https://www.dropbox.com/s/s4chl173yi4xyj8/foo.py?dl=0>) and when I run it
on a windows machine *.dump() *expands everything nicely. When I run the
same script on a Mac, it spews out a list *[[bunch o' data]]*.  Has anyone
else seen this?
----------------------------------------------------------------------------
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best practices with Bonita BPM through live exercises
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_______________________________________________
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[Pyparsing] Bug with .dump()

[mlist @dslextreme.c. <ml...@ds...>]

There is definitely a difference between the output of .dump() on Windows
and Mac. I tried on Win7 and Wn 10 and Mac OS X 10.10.


Here is an example of what I am seeing:

*Windows Output*

C:\Python27\python.exe C:/Users/qtqa/Desktop/scripts/run_moovscope.py

['Track ID', 2, 'vide', '(', 'Video', ') Enabled Not self-contained',
'Format', 'vide/avc1', 'dimensions: video', '1920x1080', 'presentation:',
'1920x1080(pixelAspect+clean)', 'cleanAperture:', '1920x1080 @ 0,0
(originTopLeft)', 'MediaTimescale:600', 'Duration:3003/60000:00:05.005',
'MinSampleDuration:20/600', 'AdvanceDecodeDelta:21/600  00:00:00.035', 'Num
data bytes:', 6555892, 'Est. data rate:', '10.479Mbps', 'Nominal
framerate:', '29.970fps', 150, ' samples', 'Frame', ' Reordering Required',
'Included in auto selection. Language code <und>', 'Dimensions:',
'1920x1080', 'CleanAperture: ', '1920x1080', 'ProductionAperture:',
'1920x1080', 'EncodedPixels:', '1920x1080', 'Track Matrix:', ' 1.0 0.0 0.0
/ 0.0 1.0 0.0 / 0.0 0.0 1.0', 1, 'edit:', ['Media start', ['0/600',
'00:00:00.000'], 'dur', ['3000/600', '00:00:05.000'], 'Track start',
['0/600', '00:00:00.000'], 'dur', ['3000/600', '00:00:05.000'], '']]

- CleanAperture: 1920x1080

- Dimensions: 1920x1080

- EncodedPixels: 1920x1080

- ProductionAperture: 1920x1080

- TrackMatrix:  1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0

- cleanAperture: 1920x1080 @ 0,0 (originTopLeft)

- data_bytes: 6555892

- decode_delta: 21/600  00:00:00.035

- edits:

  [0]:

    ['Media start', ['0/600', '00:00:00.000'], 'dur', ['3000/600',
'00:00:05.000'], 'Track start', ['0/600', '00:00:00.000'], 'dur',
['3000/600', '00:00:05.000'], '']

    - MediaDuration: ['3000/600', '00:00:05.000']

    - MediaStart: ['0/600', '00:00:00.000']

    - TrackDuration: ['3000/600', '00:00:05.000']

    - TrackStart: ['0/600', '00:00:00.000']

- estimated_data_rate: 10.479Mbps

- fps: 29.970fps

- number_of_edits: 1

- presentation: 1920x1080(pixelAspect+clean)

- sample_duration: 20/600

- samples: 150

- track_format: vide/avc1

- type: Video

- video: 1920x1080


Process finished with exit code 0


*Mac Output*

/System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7
/Users/test/Desktop/PlaybackBaseline/run_moovscope.py

['Track ID', 2, 'vide', '(', 'Video', ') Enabled Not self-contained',
'Format', 'vide/avc1', 'dimensions: video', '1920x1080', 'presentation:',
'1920x1080(pixelAspect+clean)', 'cleanAperture:', '1920x1080 @ 0,0
(originTopLeft)', 'MediaTimescale:600', 'Duration:3003/60000:00:05.005',
'MinSampleDuration:20/600', 'AdvanceDecodeDelta:21/600  00:00:00.035', 'Num
data bytes:', 6555892, 'Est. data rate:', '10.479Mbps', 'Nominal
framerate:', '29.970fps', 150, ' samples', 'Frame', ' Reordering Required',
'Included in auto selection. Language code <und>', 'Dimensions:',
'1920x1080', 'CleanAperture: ', '1920x1080', 'ProductionAperture:',
'1920x1080', 'EncodedPixels:', '1920x1080', 'Track Matrix:', ' 1.0 0.0 0.0
/ 0.0 1.0 0.0 / 0.0 0.0 1.0', 1, 'edit:', ['Media start', ['0/600',
'00:00:00.000'], 'dur', ['3000/600', '00:00:05.000'], 'Track start',
['0/600', '00:00:00.000'], 'dur', ['3000/600', '00:00:05.000'], '']]

- CleanAperture: 1920x1080

- Dimensions: 1920x1080

- EncodedPixels: 1920x1080

- ProductionAperture: 1920x1080

- TrackMatrix:  1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0

- cleanAperture: 1920x1080 @ 0,0 (originTopLeft)

- data_bytes: 6555892

- decode_delta: 21/600  00:00:00.035

- edits: [['Media start', ['0/600', '00:00:00.000'], 'dur', ['3000/600',
'00:00:05.000'], 'Track start', ['0/600', '00:00:00.000'], 'dur',
['3000/600', '00:00:05.000'], '']]

- estimated_data_rate: 10.479Mbps

- fps: 29.970fps

- number_of_edits: 1

- presentation: 1920x1080(pixelAspect+clean)

- sample_duration: 20/600

- samples: 150

- track_format: vide/avc1

- type: Video

- video: 1920x1080


Process finished with exit code 0

[Pyparsing] Difference between Mac and Windows?

[mlist @dslextreme.c. <ml...@ds...>]

I am seeing something strange. At first, I thought I was doing something
wrong, but now I wonder if it is a bug.  I have my script (Dropbox
<https://www.dropbox.com/s/s4chl173yi4xyj8/foo.py?dl=0>) and when I run it
on a windows machine *.dump() *expands everything nicely. When I run the
same script on a Mac, it spews out a list *[[bunch o' data]]*.  Has anyone
else seen this?

[Pyparsing] Problem parsing block

[Robin S. <rob...@ds...>]

I have grammar that works for almost all of my file now.  However, there 
is still one block I am having trouble with.  There are 3 blocks that 
are similar: audio track, video track and subtitle track.  For some 
reason, I can't get the correct grammar for the subtitle block. What am 
I doing wrong?


Sample Text

Track ID 1 soun (Audio) Enabled Not self-contained
     Format soun/aac  48000 Hz aac  FormatFlags: 0x00000000 Bytes/Pkt: 0 
Frames/Pkt: 1024 Bytes/Frame: 0 Chan/Frame: 2 Bits/Chan: 0 Reserved: 
0x00000000
     ChannelLayout: Stereo (L R)
     Media Timescale: 48000 Duration: 240640/48000  00:00:05.013  
MinSampleDuration: 1024/48000 AdvanceDecodeDelta: 0/48000  00:00:00.000
     Num data bytes: 80213 Est. data rate: 127.999 kbps Nominal 
framerate: 46.875 fps 235 samples
     Track volume: 1
     Included in auto selection. Language code <und>
     Dimensions: 0 x 0 Track Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
     1 edit: Media start        0/48000  00:00:00.000 dur     3000/600  
00:00:05.000 Track start        0/600  00:00:00.000 dur     3000/600  
00:00:05.000

Track ID 2 vide (Video) Enabled Not self-contained
     Format vide/avc1 dimensions: video 1920 x 1080, presentation: 1920 
x 1080 (pixelAspect+clean), cleanAperture: 1920 x 1080 @ 0,0 (originTopLeft)
     Media Timescale: 600 Duration: 3003/600  00:00:05.005  
MinSampleDuration: 20/600 AdvanceDecodeDelta: 21/600  00:00:00.035
     Num data bytes: 6555892 Est. data rate: 10.479 Mbps Nominal 
framerate: 29.970 fps 150 samples
     Frame Reordering Required
     Included in auto selection. Language code <und>
     Dimensions: 1920 x 1080 CleanAperture: 1920 x 1080 
ProductionAperture: 1920 x 1080 EncodedPixels: 1920 x 1080 Track Matrix: 
1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
     1 edit: Media start        0/600  00:00:00.000 dur     3000/600  
00:00:05.000 Track start        0/600  00:00:00.000 dur     3000/600  
00:00:05.000

Track ID 8 sbtl (Subtitles) Enabled Not self-contained
     Format sbtl/tx3g DisplayFlags: 0x00000000 Just: 0 H 0 V Default 
Text Box: 0 x 0 @ 0, 0 Default Style: Local fontID 1 Size -1 Color 
(RGBA): 1 1 1 1 Font Name: Arial
     Media Timescale: 600 Duration: 4800/600  00:00:08.000  
MinSampleDuration: 1200/600 AdvanceDecodeDelta: 0/600  00:00:00.000
     Num data bytes: 226 Est. data rate: 0.226 kbps Nominal framerate: 
0.375 fps 3 samples
     Included in auto selection. Language code <und>
     Dimensions: 0 x 0 Track Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
     2 edits:
         Media start   INVALID TIME    dur     6000/600  00:00:10.000 
Track start        0/600  00:00:00.000 dur     6000/600  00:00:10.000 
(EMPTY EDIT)
         Media start     1002/600  00:00:01.670 dur     3000/600  
00:00:05.000 Track start     6000/600  00:00:10.000 dur     3000/600  
00:00:05.000

The full code is in my dropbox - 
https://www.dropbox.com/s/s4chl173yi4xyj8/foo.py?dl=0
Here is the relevant code:


         # Define Track Info Block
         # Audio Block
         self.audio_track_info = Group(self.crap + self.track_id + 
self.audio_track_format + self.channel_layout +
                                       self.media_timescale + 
self.track_data + self.audio_track_volume +
                                       self.included + 
self.audio_track_dimensions + OneOrMore(self.edits))

         # Subtitle Block
         self.subtitle_track_info = Group(self.crap + self.track_id + 
self.subtitle_track_format) + \
                                    self.media_timescale + 
self.track_data + self.included + \
                                    self.subtitle_track_dimensions + 
OneOrMore(self.edits)

         # Video Block
         self.video_track_info = Group(self.crap + self.track_id + 
self.video_track_format + self.media_timescale +
                                       self.track_data + self.frame + 
self.included + self.video_track_dimensions +
                                       OneOrMore(self.edits))

         self.tracks = OneOrMore(self.audio_track_info | 
self.video_track_info | self.subtitle_track_info).setResultsName('tracks')

-- 
Sent with Postbox <http://www.getpostbox.com>

Re: [Pyparsing] Problem with .dump()

[Robin S. <ml...@ds...>]

I was able to revert to a previous save and everything displays 
correctly now. :)

> mlist @dslextreme.com <mailto:ml...@ds...>
> Tuesday, April 21, 2015 3:30 PM
> For some reason pastern says my paste has been removed, so I am 
> sharing it on Dropbox 
> <https://www.dropbox.com/s/s4chl173yi4xyj8/foo.py?dl=0>
>
>
> mlist @dslextreme.com <mailto:ml...@ds...>
> Tuesday, April 21, 2015 11:25 AM
> Thanks for all the help with my previous problem.  Now I almost have 
> it parsing everything I want, but I have a display problem.  When I 
> print result.track.dump(), instead of everything printing out nicely 
> in a hierarchy, everything prints out as a list, i.e. [[ bunch o' 
> data]]. I *had* it displaying correctly before, so I am sure that it 
> has something to do with grouping or ResultNames.  However, I haven't 
> been able to fix the problem via trial and error.
>
> Since the script is rather long now, I pasted it to my pastern - 
> Pastebin - pyparsing script <http://pastebin.com/u8XVEtxt>

-- 
Sent with Postbox <http://www.getpostbox.com>

Re: [Pyparsing] Problem with .dump()

[mlist @dslextreme.c. <ml...@ds...>]

For some reason pastern says my paste has been removed, so I am sharing it
on Dropbox <https://www.dropbox.com/s/s4chl173yi4xyj8/foo.py?dl=0>

On Tue, Apr 21, 2015 at 11:25 AM, mlist @dslextreme.com <
ml...@ds...> wrote:

> Thanks for all the help with my previous problem.  Now I almost have it
> parsing everything I want, but I have a display problem.  When I print
> result.track.dump(), instead of everything printing out nicely in a
> hierarchy, everything prints out as a list, i.e. [[ bunch o' data]]. I
> *had* it displaying correctly before, so I am sure that it has something
> to do with grouping or ResultNames.  However, I haven't been able to fix
> the problem via trial and error.
>
> Since the script is rather long now, I pasted it to my pastern - Pastebin
> - pyparsing script <http://pastebin.com/u8XVEtxt>
>

[Pyparsing] Problem with .dump()

[mlist @dslextreme.c. <ml...@ds...>]

Thanks for all the help with my previous problem.  Now I almost have it
parsing everything I want, but I have a display problem.  When I print
result.track.dump(), instead of everything printing out nicely in a
hierarchy, everything prints out as a list, i.e. [[ bunch o' data]]. I *had* it
displaying correctly before, so I am sure that it has something to do with
grouping or ResultNames.  However, I haven't been able to fix the problem
via trial and error.

Since the script is rather long now, I pasted it to my pastern - Pastebin -
pyparsing script <http://pastebin.com/u8XVEtxt>

Re: [Pyparsing] Dealing with blocks in different order

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

I agree with John's suggestion - define an overall grammar that is simply OneOrMore(video_block | audio_block), and then use that to parse the mixed listing of blocks.

The other way in pyparsing to treat a grammar like "A, B, C and D, in any order" is to use the Each construct in pyparsing, created using the '&' operator. So "A & B & C & D" will match the 4 elements in any order, but all 4 must be present. If some are optional, then indicate them so using Optional, as in "A & B & Optional(C) & D".  Finally, if some items might appear more than once, use ZeroOrMore or OneOrMore, as in "OneOrMore(A) & B & ZeroOrMore(C) & D". This last expression will match the repeated elements even if they are not all together, so AABADBACC would match, as would DABAAA.  ABC would *not* match, as both B and D elements are required. But for your particular case, I think just OneOrMore(A | B) should be sufficient for any combination of A's and B's.

I'm glad to see some of the other pyparsing folks stepping up to answer some questions, here and on StackOverflow. And thanks, John, for your kind comments on the help you get on the wikispaces site. As it turns out, between work and family activities for the next month or so, my participation on these lists will be limited, so I appreciate other experienced pyparsing users helping the new folks.

Cheers,
-- Paul


-----Original Message-----
From: john grant [mailto:joh...@ya...] 
Sent: Tuesday, April 21, 2015 12:41 AM
To: mlist @dslextreme.com; pyp...@li...
Subject: Re: [Pyparsing] Dealing with blocks in different order

I've been stuck on the same thing. I think I know the answer, but I have not had time to verify it. If you find one of the examples for parsing a C structure, I think it must contain the secret because the parser works no matter the order of the structure members. If my memory is correct, that example has parsers defined for each type of member (e.g. single variable, array, pointer, etc), and then there is a single parser that ORs each of the other parsers together, and the matches get inserted into a container (i.e. OneOrMore).
Let me know if you find a fix!
FYI: I've had great support on the wikispaces site. Paul has answered many of my questions. However, finding that support channel was insanely difficult. You have to go to the home page, then click Getting Help in the left side menu, then in the body of the page that appears, click the text that is underlined/hyperlinked saying "pyparsing home page" (which is poorly named).
-John
 





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Re: [Pyparsing] Dealing with blocks in different order

[Hans M. <han...@gm...>]

Hi,

Am 21.04.2015 um 07:41 schrieb john grant <joh...@ya...>:

> I've been stuck on the same thing. I think I know the answer, … that example has parsers defined for each type of member (e.g. single variable, array, pointer, etc), and then there is a single parser that ORs each of the other parsers together, and the matches get inserted into a container (i.e. OneOrMore).

Exactly that is how I would express it:

OneOrMore(Video | Audio)

Or is there anything I am missing?

Best regards,
  Hans

Re: [Pyparsing] Dealing with blocks in different order

[john g. <joh...@ya...>]

I've been stuck on the same thing. I think I know the answer, but I have not had time to verify it. If you find one of the examples for parsing a C structure, I think it must contain the secret because the parser works no matter the order of the structure members. If my memory is correct, that example has parsers defined for each type of member (e.g. single variable, array, pointer, etc), and then there is a single parser that ORs each of the other parsers together, and the matches get inserted into a container (i.e. OneOrMore).
Let me know if you find a fix!
FYI: I've had great support on the wikispaces site. Paul has answered many of my questions. However, finding that support channel was insanely difficult. You have to go to the home page, then click Getting Help in the left side menu, then in the body of the page that appears, click the text that is underlined/hyperlinked saying "pyparsing home page" (which is poorly named).
-John
 



     On Monday, April 20, 2015 12:37 PM, "mlist @dslextreme.com" <ml...@ds...> wrote:
   

 I have everything I need to parse a file defined, but I am running in to a
problem.  The main part of the file consists of different blocks (see
below) and the blocks can be in different order or not even there. I am not
sure how to deal with this.  For example, it could be

[video block]
[audio block]

or

[audio block]
[video block]

or

[video block]
[audio block]
[audio block]

or any permutation of the above.


Here is the sample text

Track ID 1 soun (Audio) Enabled Not self-contained
  Format soun/aac  48000 Hz aac  FormatFlags: 0x00000000 Bytes/Pkt: 0
Frames/Pkt: 1024 Bytes/Frame: 0 Chan/Frame: 2 Bits/Chan: 0 Reserved:
0x00000000
  ChannelLayout: Stereo (L R)
  Media Timescale: 48000 Duration: 240640/48000  00:00:05.013
MinSampleDuration: 1024/48000 AdvanceDecodeDelta: 0/48000
00:00:00.000
  Num data bytes: 80213 Est. data rate: 127.999 kbps Nominal
framerate: 46.875 fps 235 samples
  Track volume: 1
  Included in auto selection. Language code <und>
  Dimensions: 0 x 0 Track Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
  1 edit: Media start        0/48000  00:00:00.000 dur    3000/600
00:00:05.000 Track start        0/600  00:00:00.000 dur    3000/600
00:00:05.000

Track ID 2 vide (Video) Enabled Not self-contained
  Format vide/avc1 dimensions: video 1920 x 1080, presentation: 1920
x 1080 (pixelAspect+clean), cleanAperture: 1920 x 1080 @ 0,0
(originTopLeft)
  Media Timescale: 600 Duration: 3003/600  00:00:05.005
MinSampleDuration: 20/600 AdvanceDecodeDelta: 21/600  00:00:00.035
  Num data bytes: 6555892 Est. data rate: 10.479 Mbps Nominal
framerate: 29.970 fps 150 samples
  Frame Reordering Required
  Included in auto selection. Language code <und>
  Dimensions: 1920 x 1080 CleanAperture: 1920 x 1080
ProductionAperture: 1920 x 1080 EncodedPixels: 1920 x 1080 Track
Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
  1 edit: Media start        0/600  00:00:00.000 dur    3000/600
00:00:05.000 Track start        0/600  00:00:00.000 dur    3000/600
00:00:05.000



And here is what my code looks like:

# Audio Block
self.audio_track_info = Group(
  self.track_id + self.audio_track_format + self.channel_layout +
self.media_timescale +
  self.track_data + self.audio_track_volume + self.included +
  self.audio_track_dimensions +
OneOrMore(self.edits).setResultsName('edits')).setResultsName('audio_track')

# Video Block
self.video_track_info = Group(self.track_id + self.video_track_format
+ self.media_timescale + self.track_data +
                              self.included + self.video_track_dimensions +

OneOrMore(self.edits).setResultsName('edits')).setResultsName('video_track')


self.tracks = Group(ZeroOrMore(self.video_track_info)) +
Group(ZeroOrMore(self.audio_track_info)).setResultsName('tracks')

 I am using parseString on the text and this only returns the audio block
and not the video block.

How do I fix this?
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[Pyparsing] Dealing with blocks in different order

[mlist @dslextreme.c. <ml...@ds...>]

I have everything I need to parse a file defined, but I am running in to a
problem.  The main part of the file consists of different blocks (see
below) and the blocks can be in different order or not even there. I am not
sure how to deal with this.  For example, it could be

[video block]
[audio block]

or

[audio block]
[video block]

or

[video block]
[audio block]
[audio block]

or any permutation of the above.


Here is the sample text

Track ID 1 soun (Audio) Enabled Not self-contained
   Format soun/aac  48000 Hz aac  FormatFlags: 0x00000000 Bytes/Pkt: 0
Frames/Pkt: 1024 Bytes/Frame: 0 Chan/Frame: 2 Bits/Chan: 0 Reserved:
0x00000000
   ChannelLayout: Stereo (L R)
   Media Timescale: 48000 Duration: 240640/48000  00:00:05.013
MinSampleDuration: 1024/48000 AdvanceDecodeDelta: 0/48000
00:00:00.000
   Num data bytes: 80213 Est. data rate: 127.999 kbps Nominal
framerate: 46.875 fps 235 samples
   Track volume: 1
   Included in auto selection. Language code <und>
   Dimensions: 0 x 0 Track Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
   1 edit: Media start        0/48000  00:00:00.000 dur     3000/600
00:00:05.000 Track start        0/600  00:00:00.000 dur     3000/600
00:00:05.000

Track ID 2 vide (Video) Enabled Not self-contained
   Format vide/avc1 dimensions: video 1920 x 1080, presentation: 1920
x 1080 (pixelAspect+clean), cleanAperture: 1920 x 1080 @ 0,0
(originTopLeft)
   Media Timescale: 600 Duration: 3003/600  00:00:05.005
MinSampleDuration: 20/600 AdvanceDecodeDelta: 21/600  00:00:00.035
   Num data bytes: 6555892 Est. data rate: 10.479 Mbps Nominal
framerate: 29.970 fps 150 samples
   Frame Reordering Required
   Included in auto selection. Language code <und>
   Dimensions: 1920 x 1080 CleanAperture: 1920 x 1080
ProductionAperture: 1920 x 1080 EncodedPixels: 1920 x 1080 Track
Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
   1 edit: Media start        0/600  00:00:00.000 dur     3000/600
00:00:05.000 Track start        0/600  00:00:00.000 dur     3000/600
00:00:05.000



And here is what my code looks like:

# Audio Block
self.audio_track_info = Group(
   self.track_id + self.audio_track_format + self.channel_layout +
self.media_timescale +
   self.track_data + self.audio_track_volume + self.included +
   self.audio_track_dimensions +
OneOrMore(self.edits).setResultsName('edits')).setResultsName('audio_track')

# Video Block
self.video_track_info = Group(self.track_id + self.video_track_format
+ self.media_timescale + self.track_data +
                              self.included + self.video_track_dimensions +

OneOrMore(self.edits).setResultsName('edits')).setResultsName('video_track')


self.tracks = Group(ZeroOrMore(self.video_track_info)) +
Group(ZeroOrMore(self.audio_track_info)).setResultsName('tracks')

 I am using parseString on the text and this only returns the audio block
and not the video block.

How do I fix this?

[Pyparsing] Newbie question - conditional parsing/actions

[Robin S. <rob...@ds...>]

I am new to this and I am having trouble figuring out how to parse the 
below text. Much of the data in the 2 blocks below are similar. There is 
one crucial keyword that will differentiate the 2 blocks: the 1st line 
will either contain "vide (Video)" or "soun (Audio)".  I can't figure 
out how to determine which one is present in the first line and then how 
to say 'If it is "vide" do this, otherwise do that'.


Track ID 1 vide (Video) Enabled Self-contained
         Format vide/avc1 dimensions: video 1920 x 1080, presentation: 1920 x 1080 (pixelAspect+clean), cleanAperture: 1920 x 1080 @ 0,0 (originTopLeft)
         Media Timescale: 600 Duration: 14076/600  00:00:23.460  MinSampleDuration: 10/600 AdvanceDecodeDelta: 0/600  00:00:00.000
         Num data bytes: 91412686 Est. data rate: 31.172 Mbps Nominal framerate: 59.974 fps 1407 samples
         Included in auto selection. Language code<und>
         Dimensions: 1920 x 1080 CleanAperture: 1920 x 1080 ProductionAperture: 1920 x 1080 EncodedPixels: 1920 x 1080 Track Matrix: 0.0 1.0 0.0 / -1.0 0.0 0.0 / 1080.0 0.0 1.0
         1 edit: Media start        0/600  00:00:00.000 dur    14076/600  00:00:23.460 Track start        0/600  00:00:00.000 dur    14076/600  00:00:23.460

Track ID 2 soun (Audio) Enabled Self-contained
         Format soun/aac  44100 Hz aac  FormatFlags: 0x00000000 Bytes/Pkt: 0 Frames/Pkt: 1024 Bytes/Frame: 0 Chan/Frame: 1 Bits/Chan: 0 Reserved: 0x00000000
         ChannelLayout: Mono
         Media Timescale: 44100 Duration: 1037312/44100  00:00:23.522  MinSampleDuration: 1024/44100 AdvanceDecodeDelta: 0/44100  00:00:00.000
         Num data bytes: 184508 Est. data rate: 62.753 kbps Nominal framerate: 43.066 fps 1013 samples
         Track volume: 1
         Included in auto selection. Language code<und>
         Dimensions: 0 x 0 Track Matrix: 1.0 0.0 0.0 / 0.0 1.0 0.0 / 0.0 0.0 1.0
         1 edit: Media start        0/44100  00:00:00.000 dur    14076/600  00:00:23.460 Track start        0/600  00:00:00.000 dur    14076/600  00:00:23.460






-- 
Sent with Postbox <http://www.getpostbox.com>

[Pyparsing] Can I use pyparsing to parse Python?

[Moti Ben-A. <mot...@gm...>]

Hello,

I am working with a system that has its own simple programming language,
but I would like to construct a preprocessor that will translate a small
subset
of Python into this language. Can I use pyparsing to do this?

I found pythonGrammarParsing.py which seems that it might help,
but I couldn't find an explanation of how to use the bnfDefs to actually
parse a Python program.

Thanks
Moti

[Pyparsing] Mario Osorio invited you to check out Dropbox

[Dropbox <no-...@dr...>]

Hi there,

Mario Osorio wants you to try Dropbox! Dropbox lets you bring all your photos, docs, and videos with you anywhere and share them easily.

Get started here.
https://www.dropbox.com/l/1LilMq6g5aqT3DhZc7w0dr?text=1

Thanks!
- The Dropbox Team

____________________________________________________
To stop receiving invites from Dropbox, please go to https://www.dropbox.com/l/KlWHZuuQBdI7o9cDWTtWpj?text=1
Dropbox, Inc., PO Box 77767, San Francisco, CA 94107

Re: [Pyparsing] Incremental parsing with no gaps between parsed ranges?

[Dan L. <dl...@gm...>]

Daniel Lenski <dlenski <at> gmail.com> writes:

> So I think I'm going to have to do incremental parsing in order to get
> reasonably fast feedback from the parser. Do you have any suggestions 
for
> how to do this? I'm trying to figure out if there's a good way to do 
greedy
> consumption of trailing (whitespace|comments) at the end of each valid
> top-level element.

I modified parseString very slightly and came up with 
parseConsumeString().

This version calls self._parse() followed by self.preParse() repeatedly 
to do what I want when self is the parser for a "top-level" item.

    def parseConsumeString(self, instring, parseAll=False, 
yieldLoc=True, loopResetCache=False):
        if not loopResetCache:
            ParserElement.resetCache()
        if not self.streamlined:
            self.streamline()
            #~ self.saveAsList = True
        for e in self.ignoreExprs:
            e.streamline()
        if not self.keepTabs:
            instring = instring.expandtabs()
        try:
            loc = 0
            while loc<len(instring):
                sloc = loc
                if loopResetCache:
                    ParserElement.resetCache()
                loc, tokens = self._parse(instring, loc)
                if yieldLoc:
                    yield tokens, sloc, loc
                else:
                    yield tokens
                loc = self.preParse(instring, loc)
        except ParseBaseException as exc:
            if not parseAll:
                return
            if ParserElement.verbose_stacktrace:
                raise
            else:
                # catch and re-raise exception from here, clears out 
pyparsing internal stack trace
                raise exc

By the way, I moved ParserElement.resetCache() into the loop, in order 
to drastically reduce memory consumption with packrat caching. Memory 
consumption goes down from around 6G peak to around 100M peak, while 
running about 15-20% faster. This is on a Core i7 980X with 8G of RAM, 
Win7.

    In [1]: import my_parser_module as P
    
    In [2]: sample=open("large_file).read()
    In [3]: len(sample)
    Out[3]: 9153816
    
    In [4]: %timeit -n1 for r in 
P.parseConsumeString(P.TopLevel.ignore(P.COMMENT), sample, True, True, 
True): pass
    1 loops, best of 3: 1min 10s per loop
    
    In [6]: %timeit -n1 for r in 
P.parseConsumeString(P.TopLevel.ignore(P.COMMENT), sample, True, True, 
False): pass
    1 loops, best of 3: 1min 22s per loop

Thanks,
Dan

Re: [Pyparsing] Incremental parsing with no gaps between parsed ranges?

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

Before you go too far down this path, try enabling packrat parsing, which should help both performance and memory footprint.

Right after importing pyparsing, add this line:

    ParserElement.enablePackrat()


-- Paul


---- Dan Lenski <dl...@gm...> wrote: 
> I'm using PyParsing to parse some rather large text files with a C-like 
> format (braces and semicolons and all that). PyParsing works just great, 
> but it is slow and consumes a very large amount of memory due to the 
> size of my files.
> 

Re: [Pyparsing] Incremental parsing with no gaps between parsed ranges?

[Daniel L. <dl...@gm...>]

Thanks for the quick response, Paul.

With a 10 MiB input file of which no top-level element is longer than ~10
kB, it takes about 5 GiB of memory and 5 minutes before parseString()
starts returning results. I tried enablePackrat() and memory usage is
somewhat higher but speed is not appreciably improved. Based on the
docstring, I wouldn't expect enablePackrat to make a big improvement, since
every lengthy block in the grammar I'm trying to parse is introduced with a
unique keyword, so I don't think there's much backtracking-and-reparsing.

So I think I'm going to have to do incremental parsing in order to get
reasonably fast feedback from the parser. Do you have any suggestions for
how to do this? I'm trying to figure out if there's a good way to do greedy
consumption of trailing (whitespace|comments) at the end of each valid
top-level element.

-Dan

On Mon, Oct 27, 2014 at 9:17 AM, <pt...@au...> wrote:

> Before you go too far down this path, try enabling packrat parsing, which
> should help both performance and memory footprint.
>
> Right after importing pyparsing, add this line:
>
>     ParserElement.enablePackrat()
>
>
> -- Paul
>
>
> ---- Dan Lenski <dl...@gm...> wrote:
> > I'm using PyParsing to parse some rather large text files with a C-like
> > format (braces and semicolons and all that). PyParsing works just great,
> > but it is slow and consumes a very large amount of memory due to the
> > size of my files.
> >
>

[Pyparsing] Incremental parsing with no gaps between parsed ranges?

[Dan L. <dl...@gm...>]

I'm using PyParsing to parse some rather large text files with a C-like 
format (braces and semicolons and all that). PyParsing works just great, 
but it is slow and consumes a very large amount of memory due to the 
size of my files.

I wanted to try to implement an incremental parsing approach wherein I'd 
parse the top-level elements of the source file one-by-one.

The scanString method seems like the obvious way to do this. However, I 
want to make sure that there is no invalid/unparseable text in-between 
the sections parsed by scanString, and can't figure out a good way to do 
this. Here's a simplified example that shows the problem I'm having:

    sample="""f1(1,2,3); f2_no_args( );
    # comment out: foo(4,5,6);
    bar(7,8);
    this should be an error;
    baz(9,10);
    """
    
    from pyparsing import *
    
    COMMENT=Suppress('#' + restOfLine())
    SEMI,COMMA,LPAREN,RPAREN = map(Suppress,';,()')
    
    ident = Word(alphas, alphanums+"_")
    integer = Word(nums+"+-",nums)
    
    statement = ident("fn") + LPAREN + 
Group(Optional(delimitedList(integer)))("arguments") + RPAREN + SEMI
    
    p = statement.ignore(COMMENT)
    
    for res, start, end in p.scanString(sample):
        print "***** (%d,%d)" % (start, end)
        print res.dump()

When I run this, the ranges returned by scanString are discontinguous 
due to unparsed text between them ((0,10),(11,25),(53,62),(88,98)).

Two of these gaps are whitespace or comments, which should not trigger 
an error, but one of them (`this should be an error;`) contains unparse-
able text, which I want to catch.

Is there a way to use pyparsing to parse a file incrementally while 
still ensuring that the entire input could be parsed with the specified 
parser grammar? Perhaps it is possible to make scanString "greedy" so 
that it parses valid whitespace or comments following each range? If so, 
that would help me resolve this issue since it would ensure that gaps 
only occur between the returned ranges when there's an error.

Thanks,
Dan Lenski

PS-I found this related thread on the discussion board, but there 
doesn't appear to be a resolution for this issue in it: 
http://pyparsing.wikispaces.com/share/view/30891763

Re: [Pyparsing] fourFn.py explanation and slight modification

[Glenn P. <gle...@gm...>]

Hmm I got it going with this

        point = Literal( "." )
        e     = CaselessLiteral( "E" )
        fnumber = Combine( Word( "+-"+nums, nums ) +
                           Optional( point + Optional( Word( nums ) ) ) +
                           Optional( e + Word( "+-"+nums, nums ) ) )
        ident = Word(alphas, alphas+nums+"_$")
        plus  =  Literal( "+" )
        minus =  Literal( "-" )
        mult  =  Literal( "*" )
        div   =  Literal( "/" )
        lte   =  Literal( ">=" )
        lt    =  Literal( "<" )
        gt    =  Literal( ">" )
        anding = CaselessLiteral( "and" )
        oring =  CaselessLiteral( "or" )
        lpar  =  Literal( "(" ).suppress()
        rpar  =  Literal( ")" ).suppress()
        addop  = plus | minus | lte | lt | gt
        multop = mult | div
        logicalop = anding | oring
        expop = Literal( "^" )
        pi    = CaselessLiteral( "PI" )
        expr = Forward()
        atom = ((Optional(oneOf("- +")) +

 (pi|e|fnumber|ident+lpar+expr+rpar).setParseAction(self.pushFirst))
                | Optional(oneOf("- +")) + Group(lpar+expr+rpar)
                ).setParseAction(self.pushUMinus)
        # by defining exponentiation as "atom [ ^ factor ]..." instead of
        # "atom [ ^ atom ]...", we get right-to-left exponents, instead of
left-to-right
        # that is, 2^3^2 = 2^(3^2), not (2^3)^2.
        factor = Forward()
        factor <<= atom + ZeroOrMore( ( expop + factor ).setParseAction(
self.pushFirst ) )
        term = factor + ZeroOrMore( ( multop + factor ).setParseAction(
self.pushFirst ) )
        term2 = term + ZeroOrMore( ( addop + term ).setParseAction(
self.pushFirst ) )
        expr <<= term2 + ZeroOrMore( ( logicalop + term2 ).setParseAction(
self.pushFirst ) )


Can't say I 100% understand the grammer though. Any short explanations
would be great.




On 4 September 2014 10:23, Glenn Pierce <gle...@gm...> wrote:

> Hi I am new to pyparsing and I am having trouble understanding the grammer
> of the example fourFn.py
> <http://pyparsing.wikispaces.com/file/view/fourFn.py/30154950/fourFn.py>
>
> I am trying to add comparison operators and logical operators to this
> example. The comparisons work ok but I not sure how to add the logical
> operators AND OR NOT
>
> So far I have this
>
>         plus  =  Literal( "+" )
>         minus =  Literal( "-" )
>         mult  =  Literal( "*" )
>         div   =  Literal( "/" )
>         lte   =  Literal( ">=" )
>         lt    =  Literal( "<" )
>         gt    =  Literal( ">" )
>         anding = CaselessLiteral( "and" )
>         lpar  =  Literal( "(" ).suppress()
>         rpar  =  Literal( ")" ).suppress()
>         addop  = plus | minus | lte | lt | gt
>         multop = mult | div
>          expop = Literal( "^" )
>         pi    = CaselessLiteral( "PI" )
>         sensor_values = CaselessLiteral( "sensor_values" )
>         expr = Forward()
>          atom = ((Optional(oneOf("- +")) +
>
>  (sensor_values|pi|e|fnumber|ident+lpar+expr+rpar).setParseAction(self.pushFirst))
>                 | Optional(oneOf("- +")) + Group(lpar+expr+rpar)
>                 ).setParseAction(self.pushUMinus)
>         # by defining exponentiation as "atom [ ^ factor ]..." instead of
>         # "atom [ ^ atom ]...", we get right-to-left exponents, instead of
> left-to-right
>         # that is, 2^3^2 = 2^(3^2), not (2^3)^2.
>         factor = Forward()
>         factor <<= atom + ZeroOrMore( ( expop + factor ).setParseAction(
> self.pushFirst ) )
>         term = factor + ZeroOrMore( ( multop + factor ).setParseAction(
> self.pushFirst ) )
>         expr <<= term + ZeroOrMore( ( addop + term ).setParseAction(
> self.pushFirst ) )
>
>
> Could someone perhaps explain the three lines below and how I would add my
>  CaselessLiteral( "and" ) boolean
> so I could do something like
> nsp.eval('10 >= 5 AND 10 < 15')
>
> factor <<= atom + ZeroOrMore( ( expop + factor ).setParseAction(
> self.pushFirst ) )
>  term = factor + ZeroOrMore( ( multop + factor ).setParseAction(
> self.pushFirst ) )
> expr <<= term + ZeroOrMore( ( addop + term ).setParseAction(
> self.pushFirst ) )
>
>
>  PS what is the <<= operator ? I can't find the docs for it
>
> Thanks for any help.
>

[Pyparsing] fourFn.py explanation and slight modification

[Glenn P. <gle...@gm...>]

Hi I am new to pyparsing and I am having trouble understanding the grammer
of the example fourFn.py
<http://pyparsing.wikispaces.com/file/view/fourFn.py/30154950/fourFn.py>

I am trying to add comparison operators and logical operators to this
example. The comparisons work ok but I not sure how to add the logical
operators AND OR NOT

So far I have this

        plus  =  Literal( "+" )
        minus =  Literal( "-" )
        mult  =  Literal( "*" )
        div   =  Literal( "/" )
        lte   =  Literal( ">=" )
        lt    =  Literal( "<" )
        gt    =  Literal( ">" )
        anding = CaselessLiteral( "and" )
        lpar  =  Literal( "(" ).suppress()
        rpar  =  Literal( ")" ).suppress()
        addop  = plus | minus | lte | lt | gt
        multop = mult | div
        expop = Literal( "^" )
        pi    = CaselessLiteral( "PI" )
        sensor_values = CaselessLiteral( "sensor_values" )
        expr = Forward()
        atom = ((Optional(oneOf("- +")) +

 (sensor_values|pi|e|fnumber|ident+lpar+expr+rpar).setParseAction(self.pushFirst))
                | Optional(oneOf("- +")) + Group(lpar+expr+rpar)
                ).setParseAction(self.pushUMinus)
        # by defining exponentiation as "atom [ ^ factor ]..." instead of
        # "atom [ ^ atom ]...", we get right-to-left exponents, instead of
left-to-right
        # that is, 2^3^2 = 2^(3^2), not (2^3)^2.
        factor = Forward()
        factor <<= atom + ZeroOrMore( ( expop + factor ).setParseAction(
self.pushFirst ) )
        term = factor + ZeroOrMore( ( multop + factor ).setParseAction(
self.pushFirst ) )
        expr <<= term + ZeroOrMore( ( addop + term ).setParseAction(
self.pushFirst ) )


Could someone perhaps explain the three lines below and how I would add my
 CaselessLiteral( "and" ) boolean
so I could do something like
nsp.eval('10 >= 5 AND 10 < 15')

factor <<= atom + ZeroOrMore( ( expop + factor ).setParseAction(
self.pushFirst ) )
term = factor + ZeroOrMore( ( multop + factor ).setParseAction(
self.pushFirst ) )
expr <<= term + ZeroOrMore( ( addop + term ).setParseAction( self.pushFirst
) )


PS what is the <<= operator ? I can't find the docs for it

Thanks for any help.

Re: [Pyparsing] setParseAction()

[Andreas M. <and...@gm...>]

Athanasios Anastasiou wrote:

> 1) Do you really need your parsed string to be enclosed in three single
> quotes?

Actually I'm parsing a file with parseFile().

> 2) The error you are getting is reasonable. The rule p expects to start at
> the beginning of the parsed string. Be defining g as 'b'+p, you are placing
> rule p AFTER the beginning of the line (which is where the character 'b'
> will be).

But the string consists of 3 line and for the second line I created
a parser with LineStart() and LineEnd(). That's why I'm using 
LineStart() to get the beginning of the second line. Is this wrong?

What puzzles me is that the parser yields the correct results, as long
as no actions are attached to it. At least it's the result I expected.
But after adding setParseAction() it is no longer working.


Maybe I should explain my original case: I try to parse a file which has
/one/ particular line containing a few numbers separated by spaces. I do
not know how many numbers there are in this line. I just know that they
are in this particular line. Thus I need to take care about linebreak
in this line. For the rest of the file (before and after this line) I
do not need to (and don't want to) take care about linebreaks.


Ciao
Andreas

Re: [Pyparsing] setParseAction()

[Athanasios A. <ath...@gm...>]

Hello Andreas

I briefly had a look at your example and I noticed two things:

1) Do you really need your parsed string to be enclosed in three single
quotes?

2) The error you are getting is reasonable. The rule p expects to start at
the beginning of the parsed string. Be defining g as 'b'+p, you are placing
rule p AFTER the beginning of the line (which is where the character 'b'
will be).

Removing LineStart and enclosing the last string in single quotes (and of
course, escaping the line breaks) seems to be working as expected (?).

If you want to parse the string EXACTLY as it appears (including the line
breaks) you will have to include them in your rules.

Hope this helps
AA


On Thu, Aug 28, 2014 at 10:56 PM, Andreas Matthias <
and...@gm...> wrote:

> The following example works as expected. But if I uncomment the
> line ``p.setParseAction(foo)'' I get the error:
>
>    pyparsing.ParseException: Expected start of line (at char 1), (line:1,
> col:1)
>
> I do not understand what's going on here. Any help?
>
> Ciao
> Andreas
>
>
>
>    import pyparsing as pypa
>
>    p = \
>      pypa.LineStart() + \
>      pypa.OneOrMore( pypa.Literal('a').setWhitespaceChars(' ') ) + \
>      pypa.LineEnd()
>
>    def foo (t):
>        print(t)
>
>    #p.setParseAction(foo)
>
>    g = pypa.Literal('b') + p
>
>    res = g.parseString('''b
>    a a
>    a
>    ''')
>
>    print(res)
>
>
>
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[Pyparsing] setParseAction()

[Andreas M. <and...@gm...>]

The following example works as expected. But if I uncomment the
line ``p.setParseAction(foo)'' I get the error:

   pyparsing.ParseException: Expected start of line (at char 1), (line:1, col:1)

I do not understand what's going on here. Any help?

Ciao
Andreas



   import pyparsing as pypa

   p = \
     pypa.LineStart() + \
     pypa.OneOrMore( pypa.Literal('a').setWhitespaceChars(' ') ) + \
     pypa.LineEnd()

   def foo (t):
       print(t)

   #p.setParseAction(foo)

   g = pypa.Literal('b') + p

   res = g.parseString('''b
   a a
   a
   ''')

   print(res)