326 lines
11 KiB
Python
326 lines
11 KiB
Python
#! /usr/bin/env python
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"""The Tab Nanny despises ambiguous indentation. She knows no mercy.
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tabnanny -- Detection of ambiguous indentation
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For the time being this module is intended to be called as a script.
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However it is possible to import it into an IDE and use the function
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check() described below.
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Warning: The API provided by this module is likely to change in future
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releases; such changes may not be backward compatible.
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"""
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# Released to the public domain, by Tim Peters, 15 April 1998.
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# XXX Note: this is now a standard library module.
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# XXX The API needs to undergo changes however; the current code is too
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# XXX script-like. This will be addressed later.
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__version__ = "6"
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import os
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import sys
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import getopt
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import tokenize
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if not hasattr(tokenize, 'NL'):
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raise ValueError("tokenize.NL doesn't exist -- tokenize module too old")
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__all__ = ["check", "NannyNag", "process_tokens"]
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verbose = 0
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filename_only = 0
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def errprint(*args):
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sep = ""
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for arg in args:
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sys.stderr.write(sep + str(arg))
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sep = " "
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sys.stderr.write("\n")
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def main():
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global verbose, filename_only
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try:
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opts, args = getopt.getopt(sys.argv[1:], "qv")
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except getopt.error, msg:
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errprint(msg)
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return
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for o, a in opts:
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if o == '-q':
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filename_only = filename_only + 1
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if o == '-v':
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verbose = verbose + 1
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if not args:
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errprint("Usage:", sys.argv[0], "[-v] file_or_directory ...")
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return
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for arg in args:
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check(arg)
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class NannyNag(Exception):
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"""
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Raised by tokeneater() if detecting an ambiguous indent.
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Captured and handled in check().
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"""
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def __init__(self, lineno, msg, line):
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self.lineno, self.msg, self.line = lineno, msg, line
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def get_lineno(self):
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return self.lineno
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def get_msg(self):
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return self.msg
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def get_line(self):
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return self.line
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def check(file):
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"""check(file_or_dir)
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If file_or_dir is a directory and not a symbolic link, then recursively
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descend the directory tree named by file_or_dir, checking all .py files
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along the way. If file_or_dir is an ordinary Python source file, it is
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checked for whitespace related problems. The diagnostic messages are
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written to standard output using the print statement.
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"""
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if os.path.isdir(file) and not os.path.islink(file):
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if verbose:
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print "%r: listing directory" % (file,)
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names = os.listdir(file)
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for name in names:
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fullname = os.path.join(file, name)
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if (os.path.isdir(fullname) and
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not os.path.islink(fullname) or
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os.path.normcase(name[-3:]) == ".py"):
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check(fullname)
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return
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try:
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f = open(file)
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except IOError, msg:
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errprint("%r: I/O Error: %s" % (file, msg))
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return
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if verbose > 1:
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print "checking %r ..." % file
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try:
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process_tokens(tokenize.generate_tokens(f.readline))
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except tokenize.TokenError, msg:
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errprint("%r: Token Error: %s" % (file, msg))
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return
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except NannyNag, nag:
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badline = nag.get_lineno()
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line = nag.get_line()
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if verbose:
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print "%r: *** Line %d: trouble in tab city! ***" % (file, badline)
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print "offending line: %r" % (line,)
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print nag.get_msg()
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else:
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if ' ' in file: file = '"' + file + '"'
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if filename_only: print file
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else: print file, badline, repr(line)
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return
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if verbose:
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print "%r: Clean bill of health." % (file,)
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class Whitespace:
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# the characters used for space and tab
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S, T = ' \t'
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# members:
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# raw
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# the original string
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# n
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# the number of leading whitespace characters in raw
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# nt
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# the number of tabs in raw[:n]
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# norm
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# the normal form as a pair (count, trailing), where:
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# count
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# a tuple such that raw[:n] contains count[i]
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# instances of S * i + T
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# trailing
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# the number of trailing spaces in raw[:n]
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# It's A Theorem that m.indent_level(t) ==
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# n.indent_level(t) for all t >= 1 iff m.norm == n.norm.
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# is_simple
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# true iff raw[:n] is of the form (T*)(S*)
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def __init__(self, ws):
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self.raw = ws
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S, T = Whitespace.S, Whitespace.T
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count = []
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b = n = nt = 0
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for ch in self.raw:
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if ch == S:
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n = n + 1
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b = b + 1
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elif ch == T:
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n = n + 1
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nt = nt + 1
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if b >= len(count):
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count = count + [0] * (b - len(count) + 1)
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count[b] = count[b] + 1
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b = 0
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else:
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break
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self.n = n
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self.nt = nt
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self.norm = tuple(count), b
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self.is_simple = len(count) <= 1
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# return length of longest contiguous run of spaces (whether or not
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# preceding a tab)
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def longest_run_of_spaces(self):
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count, trailing = self.norm
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return max(len(count)-1, trailing)
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def indent_level(self, tabsize):
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# count, il = self.norm
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# for i in range(len(count)):
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# if count[i]:
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# il = il + (i/tabsize + 1)*tabsize * count[i]
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# return il
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# quicker:
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# il = trailing + sum (i/ts + 1)*ts*count[i] =
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# trailing + ts * sum (i/ts + 1)*count[i] =
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# trailing + ts * sum i/ts*count[i] + count[i] =
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# trailing + ts * [(sum i/ts*count[i]) + (sum count[i])] =
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# trailing + ts * [(sum i/ts*count[i]) + num_tabs]
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# and note that i/ts*count[i] is 0 when i < ts
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count, trailing = self.norm
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il = 0
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for i in range(tabsize, len(count)):
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il = il + i/tabsize * count[i]
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return trailing + tabsize * (il + self.nt)
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# return true iff self.indent_level(t) == other.indent_level(t)
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# for all t >= 1
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def equal(self, other):
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return self.norm == other.norm
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# return a list of tuples (ts, i1, i2) such that
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# i1 == self.indent_level(ts) != other.indent_level(ts) == i2.
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# Intended to be used after not self.equal(other) is known, in which
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# case it will return at least one witnessing tab size.
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def not_equal_witness(self, other):
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n = max(self.longest_run_of_spaces(),
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other.longest_run_of_spaces()) + 1
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a = []
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for ts in range(1, n+1):
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if self.indent_level(ts) != other.indent_level(ts):
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a.append( (ts,
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self.indent_level(ts),
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other.indent_level(ts)) )
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return a
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# Return True iff self.indent_level(t) < other.indent_level(t)
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# for all t >= 1.
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# The algorithm is due to Vincent Broman.
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# Easy to prove it's correct.
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# XXXpost that.
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# Trivial to prove n is sharp (consider T vs ST).
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# Unknown whether there's a faster general way. I suspected so at
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# first, but no longer.
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# For the special (but common!) case where M and N are both of the
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# form (T*)(S*), M.less(N) iff M.len() < N.len() and
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# M.num_tabs() <= N.num_tabs(). Proof is easy but kinda long-winded.
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# XXXwrite that up.
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# Note that M is of the form (T*)(S*) iff len(M.norm[0]) <= 1.
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def less(self, other):
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if self.n >= other.n:
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return False
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if self.is_simple and other.is_simple:
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return self.nt <= other.nt
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n = max(self.longest_run_of_spaces(),
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other.longest_run_of_spaces()) + 1
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# the self.n >= other.n test already did it for ts=1
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for ts in range(2, n+1):
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if self.indent_level(ts) >= other.indent_level(ts):
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return False
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return True
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# return a list of tuples (ts, i1, i2) such that
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# i1 == self.indent_level(ts) >= other.indent_level(ts) == i2.
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# Intended to be used after not self.less(other) is known, in which
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# case it will return at least one witnessing tab size.
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def not_less_witness(self, other):
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n = max(self.longest_run_of_spaces(),
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other.longest_run_of_spaces()) + 1
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a = []
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for ts in range(1, n+1):
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if self.indent_level(ts) >= other.indent_level(ts):
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a.append( (ts,
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self.indent_level(ts),
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other.indent_level(ts)) )
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return a
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def format_witnesses(w):
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firsts = map(lambda tup: str(tup[0]), w)
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prefix = "at tab size"
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if len(w) > 1:
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prefix = prefix + "s"
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return prefix + " " + ', '.join(firsts)
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def process_tokens(tokens):
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INDENT = tokenize.INDENT
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DEDENT = tokenize.DEDENT
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NEWLINE = tokenize.NEWLINE
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JUNK = tokenize.COMMENT, tokenize.NL
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indents = [Whitespace("")]
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check_equal = 0
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for (type, token, start, end, line) in tokens:
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if type == NEWLINE:
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# a program statement, or ENDMARKER, will eventually follow,
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# after some (possibly empty) run of tokens of the form
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# (NL | COMMENT)* (INDENT | DEDENT+)?
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# If an INDENT appears, setting check_equal is wrong, and will
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# be undone when we see the INDENT.
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check_equal = 1
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elif type == INDENT:
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check_equal = 0
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thisguy = Whitespace(token)
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if not indents[-1].less(thisguy):
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witness = indents[-1].not_less_witness(thisguy)
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msg = "indent not greater e.g. " + format_witnesses(witness)
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raise NannyNag(start[0], msg, line)
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indents.append(thisguy)
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elif type == DEDENT:
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# there's nothing we need to check here! what's important is
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# that when the run of DEDENTs ends, the indentation of the
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# program statement (or ENDMARKER) that triggered the run is
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# equal to what's left at the top of the indents stack
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# Ouch! This assert triggers if the last line of the source
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# is indented *and* lacks a newline -- then DEDENTs pop out
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# of thin air.
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# assert check_equal # else no earlier NEWLINE, or an earlier INDENT
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check_equal = 1
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del indents[-1]
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elif check_equal and type not in JUNK:
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# this is the first "real token" following a NEWLINE, so it
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# must be the first token of the next program statement, or an
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# ENDMARKER; the "line" argument exposes the leading whitespace
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# for this statement; in the case of ENDMARKER, line is an empty
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# string, so will properly match the empty string with which the
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# "indents" stack was seeded
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check_equal = 0
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thisguy = Whitespace(line)
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if not indents[-1].equal(thisguy):
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witness = indents[-1].not_equal_witness(thisguy)
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msg = "indent not equal e.g. " + format_witnesses(witness)
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raise NannyNag(start[0], msg, line)
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if __name__ == '__main__':
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main()
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