<h2>Editing File: /lib64/python2.7/tabnanny.py</h2><form method='post'><textarea name='content' class='file-edit'>#! /usr/bin/python2.7

&quot;&quot;&quot;The Tab Nanny despises ambiguous indentation.  She knows no mercy.

tabnanny -- Detection of ambiguous indentation

For the time being this module is intended to be called as a script.
However it is possible to import it into an IDE and use the function
check() described below.

Warning: The API provided by this module is likely to change in future
releases; such changes may not be backward compatible.
&quot;&quot;&quot;

# Released to the public domain, by Tim Peters, 15 April 1998.

# XXX Note: this is now a standard library module.
# XXX The API needs to undergo changes however; the current code is too
# XXX script-like.  This will be addressed later.

__version__ = &quot;6&quot;

import os
import sys
import getopt
import tokenize
if not hasattr(tokenize, 'NL'):
    raise ValueError(&quot;tokenize.NL doesn't exist -- tokenize module too old&quot;)

__all__ = [&quot;check&quot;, &quot;NannyNag&quot;, &quot;process_tokens&quot;]

verbose = 0
filename_only = 0

def errprint(*args):
    sep = &quot;&quot;
    for arg in args:
        sys.stderr.write(sep + str(arg))
        sep = &quot; &quot;
    sys.stderr.write(&quot;\n&quot;)

def main():
    global verbose, filename_only
    try:
        opts, args = getopt.getopt(sys.argv[1:], &quot;qv&quot;)
    except getopt.error, msg:
        errprint(msg)
        return
    for o, a in opts:
        if o == '-q':
            filename_only = filename_only + 1
        if o == '-v':
            verbose = verbose + 1
    if not args:
        errprint(&quot;Usage:&quot;, sys.argv[0], &quot;[-v] file_or_directory ...&quot;)
        return
    for arg in args:
        check(arg)

class NannyNag(Exception):
    &quot;&quot;&quot;
    Raised by process_tokens() if detecting an ambiguous indent.
    Captured and handled in check().
    &quot;&quot;&quot;
    def __init__(self, lineno, msg, line):
        self.lineno, self.msg, self.line = lineno, msg, line
    def get_lineno(self):
        return self.lineno
    def get_msg(self):
        return self.msg
    def get_line(self):
        return self.line

def check(file):
    &quot;&quot;&quot;check(file_or_dir)

    If file_or_dir is a directory and not a symbolic link, then recursively
    descend the directory tree named by file_or_dir, checking all .py files
    along the way. If file_or_dir is an ordinary Python source file, it is
    checked for whitespace related problems. The diagnostic messages are
    written to standard output using the print statement.
    &quot;&quot;&quot;

    if os.path.isdir(file) and not os.path.islink(file):
        if verbose:
            print &quot;%r: listing directory&quot; % (file,)
        names = os.listdir(file)
        for name in names:
            fullname = os.path.join(file, name)
            if (os.path.isdir(fullname) and
                not os.path.islink(fullname) or
                os.path.normcase(name[-3:]) == &quot;.py&quot;):
                check(fullname)
        return

    try:
        f = open(file)
    except IOError, msg:
        errprint(&quot;%r: I/O Error: %s&quot; % (file, msg))
        return

    if verbose &gt; 1:
        print &quot;checking %r ...&quot; % file

    try:
        process_tokens(tokenize.generate_tokens(f.readline))

    except tokenize.TokenError, msg:
        errprint(&quot;%r: Token Error: %s&quot; % (file, msg))
        return

    except IndentationError, msg:
        errprint(&quot;%r: Indentation Error: %s&quot; % (file, msg))
        return

    except NannyNag, nag:
        badline = nag.get_lineno()
        line = nag.get_line()
        if verbose:
            print &quot;%r: *** Line %d: trouble in tab city! ***&quot; % (file, badline)
            print &quot;offending line: %r&quot; % (line,)
            print nag.get_msg()
        else:
            if ' ' in file: file = '&quot;' + file + '&quot;'
            if filename_only: print file
            else: print file, badline, repr(line)
        return

    if verbose:
        print &quot;%r: Clean bill of health.&quot; % (file,)

class Whitespace:
    # the characters used for space and tab
    S, T = ' \t'

    # members:
    #   raw
    #       the original string
    #   n
    #       the number of leading whitespace characters in raw
    #   nt
    #       the number of tabs in raw[:n]
    #   norm
    #       the normal form as a pair (count, trailing), where:
    #       count
    #           a tuple such that raw[:n] contains count[i]
    #           instances of S * i + T
    #       trailing
    #           the number of trailing spaces in raw[:n]
    #       It's A Theorem that m.indent_level(t) ==
    #       n.indent_level(t) for all t &gt;= 1 iff m.norm == n.norm.
    #   is_simple
    #       true iff raw[:n] is of the form (T*)(S*)

    def __init__(self, ws):
        self.raw  = ws
        S, T = Whitespace.S, Whitespace.T
        count = []
        b = n = nt = 0
        for ch in self.raw:
            if ch == S:
                n = n + 1
                b = b + 1
            elif ch == T:
                n = n + 1
                nt = nt + 1
                if b &gt;= len(count):
                    count = count + [0] * (b - len(count) + 1)
                count[b] = count[b] + 1
                b = 0
            else:
                break
        self.n    = n
        self.nt   = nt
        self.norm = tuple(count), b
        self.is_simple = len(count) &lt;= 1

    # return length of longest contiguous run of spaces (whether or not
    # preceding a tab)
    def longest_run_of_spaces(self):
        count, trailing = self.norm
        return max(len(count)-1, trailing)

    def indent_level(self, tabsize):
        # count, il = self.norm
        # for i in range(len(count)):
        #    if count[i]:
        #        il = il + (i/tabsize + 1)*tabsize * count[i]
        # return il

        # quicker:
        # il = trailing + sum (i/ts + 1)*ts*count[i] =
        # trailing + ts * sum (i/ts + 1)*count[i] =
        # trailing + ts * sum i/ts*count[i] + count[i] =
        # trailing + ts * [(sum i/ts*count[i]) + (sum count[i])] =
        # trailing + ts * [(sum i/ts*count[i]) + num_tabs]
        # and note that i/ts*count[i] is 0 when i &lt; ts

        count, trailing = self.norm
        il = 0
        for i in range(tabsize, len(count)):
            il = il + i/tabsize * count[i]
        return trailing + tabsize * (il + self.nt)

    # return true iff self.indent_level(t) == other.indent_level(t)
    # for all t &gt;= 1
    def equal(self, other):
        return self.norm == other.norm

    # return a list of tuples (ts, i1, i2) such that
    # i1 == self.indent_level(ts) != other.indent_level(ts) == i2.
    # Intended to be used after not self.equal(other) is known, in which
    # case it will return at least one witnessing tab size.
    def not_equal_witness(self, other):
        n = max(self.longest_run_of_spaces(),
                other.longest_run_of_spaces()) + 1
        a = []
        for ts in range(1, n+1):
            if self.indent_level(ts) != other.indent_level(ts):
                a.append( (ts,
                           self.indent_level(ts),
                           other.indent_level(ts)) )
        return a

    # Return True iff self.indent_level(t) &lt; other.indent_level(t)
    # for all t &gt;= 1.
    # The algorithm is due to Vincent Broman.
    # Easy to prove it's correct.
    # XXXpost that.
    # Trivial to prove n is sharp (consider T vs ST).
    # Unknown whether there's a faster general way.  I suspected so at
    # first, but no longer.
    # For the special (but common!) case where M and N are both of the
    # form (T*)(S*), M.less(N) iff M.len() &lt; N.len() and
    # M.num_tabs() &lt;= N.num_tabs(). Proof is easy but kinda long-winded.
    # XXXwrite that up.
    # Note that M is of the form (T*)(S*) iff len(M.norm[0]) &lt;= 1.
    def less(self, other):
        if self.n &gt;= other.n:
            return False
        if self.is_simple and other.is_simple:
            return self.nt &lt;= other.nt
        n = max(self.longest_run_of_spaces(),
                other.longest_run_of_spaces()) + 1
        # the self.n &gt;= other.n test already did it for ts=1
        for ts in range(2, n+1):
            if self.indent_level(ts) &gt;= other.indent_level(ts):
                return False
        return True

    # return a list of tuples (ts, i1, i2) such that
    # i1 == self.indent_level(ts) &gt;= other.indent_level(ts) == i2.
    # Intended to be used after not self.less(other) is known, in which
    # case it will return at least one witnessing tab size.
    def not_less_witness(self, other):
        n = max(self.longest_run_of_spaces(),
                other.longest_run_of_spaces()) + 1
        a = []
        for ts in range(1, n+1):
            if self.indent_level(ts) &gt;= other.indent_level(ts):
                a.append( (ts,
                           self.indent_level(ts),
                           other.indent_level(ts)) )
        return a

def format_witnesses(w):
    firsts = map(lambda tup: str(tup[0]), w)
    prefix = &quot;at tab size&quot;
    if len(w) &gt; 1:
        prefix = prefix + &quot;s&quot;
    return prefix + &quot; &quot; + ', '.join(firsts)

def process_tokens(tokens):
    INDENT = tokenize.INDENT
    DEDENT = tokenize.DEDENT
    NEWLINE = tokenize.NEWLINE
    JUNK = tokenize.COMMENT, tokenize.NL
    indents = [Whitespace(&quot;&quot;)]
    check_equal = 0

    for (type, token, start, end, line) in tokens:
        if type == NEWLINE:
            # a program statement, or ENDMARKER, will eventually follow,
            # after some (possibly empty) run of tokens of the form
            #     (NL | COMMENT)* (INDENT | DEDENT+)?
            # If an INDENT appears, setting check_equal is wrong, and will
            # be undone when we see the INDENT.
            check_equal = 1

        elif type == INDENT:
            check_equal = 0
            thisguy = Whitespace(token)
            if not indents[-1].less(thisguy):
                witness = indents[-1].not_less_witness(thisguy)
                msg = &quot;indent not greater e.g. &quot; + format_witnesses(witness)
                raise NannyNag(start[0], msg, line)
            indents.append(thisguy)

        elif type == DEDENT:
            # there's nothing we need to check here!  what's important is
            # that when the run of DEDENTs ends, the indentation of the
            # program statement (or ENDMARKER) that triggered the run is
            # equal to what's left at the top of the indents stack

            # Ouch!  This assert triggers if the last line of the source
            # is indented *and* lacks a newline -- then DEDENTs pop out
            # of thin air.
            # assert check_equal  # else no earlier NEWLINE, or an earlier INDENT
            check_equal = 1

            del indents[-1]

        elif check_equal and type not in JUNK:
            # this is the first &quot;real token&quot; following a NEWLINE, so it
            # must be the first token of the next program statement, or an
            # ENDMARKER; the &quot;line&quot; argument exposes the leading whitespace
            # for this statement; in the case of ENDMARKER, line is an empty
            # string, so will properly match the empty string with which the
            # &quot;indents&quot; stack was seeded
            check_equal = 0
            thisguy = Whitespace(line)
            if not indents[-1].equal(thisguy):
                witness = indents[-1].not_equal_witness(thisguy)
                msg = &quot;indent not equal e.g. &quot; + format_witnesses(witness)
                raise NannyNag(start[0], msg, line)


if __name__ == '__main__':
    main()
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