https://github.com/zacharyvoase/strscan

A simple string scanner class for Python. Useful for building lexers/tokenizers by hand.
https://github.com/zacharyvoase/strscan

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A simple string scanner class for Python. Useful for building lexers/tokenizers by hand.

• Host: GitHub
• URL: https://github.com/zacharyvoase/strscan
• Owner: zacharyvoase
• License: unlicense
• Created: 2011-02-11T10:50:13.000Z (over 14 years ago)
• Default Branch: master
• Last Pushed: 2011-02-13T05:51:10.000Z (over 14 years ago)
• Last Synced: 2024-11-16T08:06:58.240Z (11 months ago)
• Language: Python
• Homepage: http://zacharyvoase.github.com/strscan/
• Size: 162 KB
• Stars: 6
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

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README

          
strscan

=======

``strscan.Scanner`` is a near-direct port of Ruby's ``StringScanner``.

The aim is to provide for lexical scanning operations on strings::

    >>> from strscan import Scanner

    >>> s = Scanner("This is an example string")

    >>> s.eos()

    False

    >>> s.scan(r'\w+')

    'This'

    >>> s.scan(r'\w+')

    >>> s.scan(r'\s+')

    ' '

    >>> s.scan(r'\s+')

    >>> s.scan(r'\w+')

    'is'

    >>> s.eos()

    False

    >>> s.scan(r'\s+')

    ' '

    >>> s.scan(r'\w+')

    'an'

    >>> s.scan(r'\s+')

    ' '

    >>> s.scan(r'\w+')

    'example'

    >>> s.scan(r'\s+')

    ' '

    >>> s.scan(r'\w+')

    'string'

    >>> s.eos()

    True

    >>> s.scan(r'\s+')

    >>> s.scan(r'\w+')

Its mechanism of operation is similar to ``StringIO``, only instead of reading

by passing a number of bytes, you read by passing a regex. A scan pointer

tracks the current position through the string, and all scanning or searching

happens on the rest of the string after this pointer.  ``scan`` is the simple

case of reading some text and advancing the scan pointer, but there are several

other related methods which fulfil different requirements.

All the methods on ``Scanner`` which take regexes will accept either regex

strings or compiled pattern objects (as would be returned from

``re.compile()``).

``text_coords()``

-----------------

There's also a useful function provided, ``text_coords()``, which resolves

simple string indices into textual co-ordinates (line number and column)::

    >>> s = "abcdef\nghijkl\nmnopqr\nstuvwx\nyz"

    >>> text_coords(s, 0)

    (0, 0, 'abcdef')

    >>> text_coords(s, 4)

    (0, 4, 'abcdef')

    >>> text_coords(s, 6)

    (0, 6, 'abcdef')

    >>> text_coords(s, 7)

    (1, 0, 'ghijkl')

    >>> text_coords(s, 11)

    (1, 4, 'ghijkl')

    >>> text_coords(s, 15)

    (2, 1, 'mnopqr')

Installation

------------

You can get the module from PyPI::

    pip install strscan

(Un)license

===========

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute this

software, either in source code form or as a compiled binary, for any purpose,

commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this

software dedicate any and all copyright interest in the software to the public

domain. We make this dedication for the benefit of the public at large and to

the detriment of our heirs and successors. We intend this dedication to be an

overt act of relinquishment in perpetuity of all present and future rights to

this software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE

AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to