Problem with lineStart

[Larry Maccherone]

If I run this code:
---------
from pyparsing import *
directive = (lineStart +
             Combine(Literal('#') + restOfLine))
directive_statement = (ZeroOrMore(cppStyleComment) + directive)
s = """
// preceding comment
# directive - OK

    // preceding comment
    # directive with preceding whitespace and comment - OK

    # directive with preceding whitespace - DOES NOT WORK
"""
for t in directive.scanString(s):
    print t

for t in directive_statement.scanString(s):
    print t
---------
It doesn't seem to find the directive_statement with the preceding whitespace but no preceding comment.  I even tried it with an explicit White().

[Paul McGuire]

???  Your program looks like it's okay for me.  Here's the output:

((['#', ' directive - OK'], {}), 21, 38)
((['#', ' directive with preceding whitespace and comment - OK'], {}), 64, 123)
((['#', ' directive with preceding whitespace - DOES NOT WORK'], {}), 123, 182)
((['// preceding comment', '#', ' directive - OK'], {}), 1, 38)
((['// preceding comment', '#', ' directive with preceding whitespace and comment - OK'], {}), 44, 123)

What version of pyparsing are you running?  I tested this successfully with 1.4.1, and also with the upcoming 1.4.2, and both gave this output.

-- Paul

[Larry Maccherone]

Thanks for the quick response both today and yesterday. 

I get the same output as you.  I'm using 1.4.1.  However, that's not the desired output.

My test code runs the two different scanners - the "directive" one first and then the "directive_statement" one next.  The "directive_statement" scanner is missing the third directive.  Only the "directive" scanner picks it up.  Notice the missing "DOES NOT WORK" line in the second run. 

Sorry about the confusion.  I should have labled the output better.

Once again, great tool and thanks.

Larry

[Paul McGuire]

Try this:

from pyparsing import *
directive = lineStart + Optional(White()) + Combine(Literal('#') + restOfLine) + Suppress(lineEnd)
directive_statement = ZeroOrMore(cppStyleComment) + directive
directive_statement.leaveWhitespace()

The problem is that lineStart is pretty touchy about being tested exactly at col 1, and it's possible that col 1 was already skipped over during default whitespace skipping.

I might take a look at making lineStart a little more tolerant of being tested at the logical line start, not just "at col 1".

-- Paul