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- #! /usr/bin/env python3
- """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.
- """
- # 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__ = "6"
- import os
- import sys
- import tokenize
- if not hasattr(tokenize, 'NL'):
- raise ValueError("tokenize.NL doesn't exist -- tokenize module too old")
- __all__ = ["check", "NannyNag", "process_tokens"]
- verbose = 0
- filename_only = 0
- def errprint(*args):
- sep = ""
- for arg in args:
- sys.stderr.write(sep + str(arg))
- sep = " "
- sys.stderr.write("\n")
- def main():
- import getopt
- global verbose, filename_only
- try:
- opts, args = getopt.getopt(sys.argv[1:], "qv")
- except getopt.error as 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("Usage:", sys.argv[0], "[-v] file_or_directory ...")
- return
- for arg in args:
- check(arg)
- class NannyNag(Exception):
- """
- Raised by process_tokens() if detecting an ambiguous indent.
- Captured and handled in check().
- """
- 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):
- """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.
- """
- if os.path.isdir(file) and not os.path.islink(file):
- if verbose:
- print("%r: listing directory" % (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:]) == ".py"):
- check(fullname)
- return
- try:
- f = tokenize.open(file)
- except OSError as msg:
- errprint("%r: I/O Error: %s" % (file, msg))
- return
- if verbose > 1:
- print("checking %r ..." % file)
- try:
- process_tokens(tokenize.generate_tokens(f.readline))
- except tokenize.TokenError as msg:
- errprint("%r: Token Error: %s" % (file, msg))
- return
- except IndentationError as msg:
- errprint("%r: Indentation Error: %s" % (file, msg))
- return
- except NannyNag as nag:
- badline = nag.get_lineno()
- line = nag.get_line()
- if verbose:
- print("%r: *** Line %d: trouble in tab city! ***" % (file, badline))
- print("offending line: %r" % (line,))
- print(nag.get_msg())
- else:
- if ' ' in file: file = '"' + file + '"'
- if filename_only: print(file)
- else: print(file, badline, repr(line))
- return
- finally:
- f.close()
- if verbose:
- print("%r: Clean bill of health." % (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 >= 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 >= 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) <= 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 < 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 >= 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) < other.indent_level(t)
- # for all t >= 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() < N.len() and
- # M.num_tabs() <= 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]) <= 1.
- def less(self, other):
- if self.n >= other.n:
- return False
- if self.is_simple and other.is_simple:
- return self.nt <= other.nt
- n = max(self.longest_run_of_spaces(),
- other.longest_run_of_spaces()) + 1
- # the self.n >= other.n test already did it for ts=1
- for ts in range(2, n+1):
- if self.indent_level(ts) >= other.indent_level(ts):
- return False
- return True
- # 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.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) >= other.indent_level(ts):
- a.append( (ts,
- self.indent_level(ts),
- other.indent_level(ts)) )
- return a
- def format_witnesses(w):
- firsts = (str(tup[0]) for tup in w)
- prefix = "at tab size"
- if len(w) > 1:
- prefix = prefix + "s"
- return prefix + " " + ', '.join(firsts)
- def process_tokens(tokens):
- INDENT = tokenize.INDENT
- DEDENT = tokenize.DEDENT
- NEWLINE = tokenize.NEWLINE
- JUNK = tokenize.COMMENT, tokenize.NL
- indents = [Whitespace("")]
- 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 = "indent not greater e.g. " + 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 "real token" following a NEWLINE, so it
- # must be the first token of the next program statement, or an
- # ENDMARKER; the "line" 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
- # "indents" stack was seeded
- check_equal = 0
- thisguy = Whitespace(line)
- if not indents[-1].equal(thisguy):
- witness = indents[-1].not_equal_witness(thisguy)
- msg = "indent not equal e.g. " + format_witnesses(witness)
- raise NannyNag(start[0], msg, line)
- if __name__ == '__main__':
- main()
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