Hi all,
I have a question on PyParsing. I am trying to create a parser for a
hierarchical todo list format, but have hit a stumbling block. I have
parsers for the header of the list (title and description), and the body
(recursive descent on todo items).
Individually they are working fine, combined they throw an exception.
The code follows:
#!/usr/bin/python
# parser.py
import pyparsing as pp
def grammar():
underline = pp.Word("=").suppress()
dotnum = pp.Combine(pp.Word(pp.nums) + ".")
textline = pp.Combine(pp.Group(pp.Word(pp.alphas, pp.printables) +
pp.restOfLine))
number = pp.Group(pp.OneOrMore(dotnum))
headtitle = textline
headdescription = pp.ZeroOrMore(textline)
head = pp.Group(headtitle + underline + headdescription)
taskname = pp.OneOrMore(dotnum) + textline
task = pp.Forward()
subtask = pp.Group(dotnum + task)
task << (taskname + pp.ZeroOrMore(subtask))
maintask = pp.Group(pp.LineStart() + task)
parser = pp.OneOrMore(maintask)
return head, parser
text = """
My Title
========
Text on a longer line of several words.
More test
and more.
"""
text2 = """
1. Task 1
1.1. Subtask
1.1.1. More tasks.
1.2. Another subtask
2. Task 2
2.1. Subtask again"""
head, parser = grammar()
print head.parseString(text)
print parser.parseString(text2)
comb = head + pp.OneOrMore(pp.LineStart() + pp.restOfLine) + parser
print comb.parseString(text + text2)
#===================================================================
Now the first two print statements output the parse tree as I would
expect, but the combined parser fails with an exception:
Traceback (most recent call last):
File "parser.py", line 50, in ?
print comb.parseString(text + text2)
.
. [Stacktrace snipped]
.
raise exc
pyparsing.ParseException: Expected start of line (at char 81), (line:9,
col:1)
Any help appreciated!
Cheers,
--
Ant.
--
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