Coverage for cogapp\whiteutils : 92%

""" Indentation utilities for Cog.

    http://nedbatchelder.com/code/cog

    Copyright 2004-2009, Ned Batchelder.

"""

import re

def whitePrefix(strings):

    """ Determine the whitespace prefix common to all non-blank lines

        in the argument list.

    """

    # Remove all blank lines from the list

    strings = [s for s in strings if s.strip() != '']

    if not strings: return ''

    # Find initial whitespace chunk in the first line.

    # This is the best prefix we can hope for.

    prefix = re.match(r'\s*', strings[0]).group(0)

    # Loop over the other strings, keeping only as much of

    # the prefix as matches each string.

    for s in strings:

        for i in range(len(prefix)):

            if prefix[i] != s[i]:

                prefix = prefix[:i]

                break

    return prefix

def reindentBlock(lines, newIndent=''):

    """ Take a block of text as a string or list of lines.

        Remove any common whitespace indentation.

        Re-indent using newIndent, and return it as a single string.

    """

    if isinstance(lines, basestring):

        lines = lines.split('\n')

    oldIndent = whitePrefix(lines)

    outLines = []

    for l in lines:

        if oldIndent:

            l = l.replace(oldIndent, '', 1)

        if l and newIndent:

            l = newIndent + l

        outLines.append(l)

    return '\n'.join(outLines)

def commonPrefix(strings):

    """ Find the longest string that is a prefix of all the strings.

    """

    if not strings:

        return ''

    prefix = strings[0]

    for s in strings:

        if len(s) < len(prefix):

            prefix = prefix[:len(s)]

        if not prefix:

            return ''

        for i in range(len(prefix)):

            if prefix[i] != s[i]:

                prefix = prefix[:i]

                break

    return prefix