| 1 | #! /usr/bin/env python
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| 2 |
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| 3 | """The Tab Nanny despises ambiguous indentation. She knows no mercy.
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| 4 |
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| 5 | tabnanny -- Detection of ambiguous indentation
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| 6 |
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| 7 | For the time being this module is intended to be called as a script.
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| 8 | However it is possible to import it into an IDE and use the function
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| 9 | check() described below.
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| 10 |
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| 11 | Warning: The API provided by this module is likely to change in future
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| 12 | releases; such changes may not be backward compatible.
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| 13 | """
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| 14 |
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| 15 | # Released to the public domain, by Tim Peters, 15 April 1998.
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| 16 |
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| 17 | # XXX Note: this is now a standard library module.
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| 18 | # XXX The API needs to undergo changes however; the current code is too
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| 19 | # XXX script-like. This will be addressed later.
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| 20 |
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| 21 | __version__ = "6"
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| 22 |
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| 23 | import os
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| 24 | import sys
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| 25 | import getopt
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| 26 | import tokenize
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| 27 | if not hasattr(tokenize, 'NL'):
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| 28 | raise ValueError("tokenize.NL doesn't exist -- tokenize module too old")
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| 29 |
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| 30 | __all__ = ["check", "NannyNag", "process_tokens"]
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| 31 |
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| 32 | verbose = 0
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| 33 | filename_only = 0
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| 34 |
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| 35 | def errprint(*args):
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| 36 | sep = ""
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| 37 | for arg in args:
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| 38 | sys.stderr.write(sep + str(arg))
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| 39 | sep = " "
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| 40 | sys.stderr.write("\n")
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| 41 |
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| 42 | def main():
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| 43 | global verbose, filename_only
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| 44 | try:
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| 45 | opts, args = getopt.getopt(sys.argv[1:], "qv")
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| 46 | except getopt.error, msg:
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| 47 | errprint(msg)
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| 48 | return
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| 49 | for o, a in opts:
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| 50 | if o == '-q':
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| 51 | filename_only = filename_only + 1
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| 52 | if o == '-v':
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| 53 | verbose = verbose + 1
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| 54 | if not args:
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| 55 | errprint("Usage:", sys.argv[0], "[-v] file_or_directory ...")
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| 56 | return
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| 57 | for arg in args:
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| 58 | check(arg)
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| 59 |
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| 60 | class NannyNag(Exception):
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| 61 | """
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| 62 | Raised by tokeneater() if detecting an ambiguous indent.
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| 63 | Captured and handled in check().
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| 64 | """
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| 65 | def __init__(self, lineno, msg, line):
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| 66 | self.lineno, self.msg, self.line = lineno, msg, line
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| 67 | def get_lineno(self):
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| 68 | return self.lineno
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| 69 | def get_msg(self):
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| 70 | return self.msg
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| 71 | def get_line(self):
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| 72 | return self.line
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| 73 |
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| 74 | def check(file):
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| 75 | """check(file_or_dir)
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| 76 |
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| 77 | If file_or_dir is a directory and not a symbolic link, then recursively
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| 78 | descend the directory tree named by file_or_dir, checking all .py files
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| 79 | along the way. If file_or_dir is an ordinary Python source file, it is
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| 80 | checked for whitespace related problems. The diagnostic messages are
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| 81 | written to standard output using the print statement.
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| 82 | """
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| 83 |
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| 84 | if os.path.isdir(file) and not os.path.islink(file):
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| 85 | if verbose:
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| 86 | print "%r: listing directory" % (file,)
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| 87 | names = os.listdir(file)
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| 88 | for name in names:
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| 89 | fullname = os.path.join(file, name)
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| 90 | if (os.path.isdir(fullname) and
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| 91 | not os.path.islink(fullname) or
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| 92 | os.path.normcase(name[-3:]) == ".py"):
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| 93 | check(fullname)
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| 94 | return
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| 95 |
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| 96 | try:
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| 97 | f = open(file)
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| 98 | except IOError, msg:
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| 99 | errprint("%r: I/O Error: %s" % (file, msg))
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| 100 | return
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| 101 |
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| 102 | if verbose > 1:
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| 103 | print "checking %r ..." % file
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| 104 |
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| 105 | try:
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| 106 | process_tokens(tokenize.generate_tokens(f.readline))
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| 107 |
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| 108 | except tokenize.TokenError, msg:
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| 109 | errprint("%r: Token Error: %s" % (file, msg))
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| 110 | return
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| 111 |
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| 112 | except IndentationError, msg:
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| 113 | errprint("%r: Indentation Error: %s" % (file, msg))
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| 114 | return
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| 115 |
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| 116 | except NannyNag, nag:
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| 117 | badline = nag.get_lineno()
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| 118 | line = nag.get_line()
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| 119 | if verbose:
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| 120 | print "%r: *** Line %d: trouble in tab city! ***" % (file, badline)
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| 121 | print "offending line: %r" % (line,)
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| 122 | print nag.get_msg()
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| 123 | else:
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| 124 | if ' ' in file: file = '"' + file + '"'
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| 125 | if filename_only: print file
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| 126 | else: print file, badline, repr(line)
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| 127 | return
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| 128 |
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| 129 | if verbose:
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| 130 | print "%r: Clean bill of health." % (file,)
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| 131 |
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| 132 | class Whitespace:
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| 133 | # the characters used for space and tab
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| 134 | S, T = ' \t'
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| 135 |
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| 136 | # members:
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| 137 | # raw
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| 138 | # the original string
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| 139 | # n
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| 140 | # the number of leading whitespace characters in raw
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| 141 | # nt
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| 142 | # the number of tabs in raw[:n]
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| 143 | # norm
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| 144 | # the normal form as a pair (count, trailing), where:
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| 145 | # count
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| 146 | # a tuple such that raw[:n] contains count[i]
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| 147 | # instances of S * i + T
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| 148 | # trailing
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| 149 | # the number of trailing spaces in raw[:n]
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| 150 | # It's A Theorem that m.indent_level(t) ==
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| 151 | # n.indent_level(t) for all t >= 1 iff m.norm == n.norm.
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| 152 | # is_simple
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| 153 | # true iff raw[:n] is of the form (T*)(S*)
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| 154 |
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| 155 | def __init__(self, ws):
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| 156 | self.raw = ws
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| 157 | S, T = Whitespace.S, Whitespace.T
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| 158 | count = []
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| 159 | b = n = nt = 0
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| 160 | for ch in self.raw:
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| 161 | if ch == S:
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| 162 | n = n + 1
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| 163 | b = b + 1
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| 164 | elif ch == T:
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| 165 | n = n + 1
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| 166 | nt = nt + 1
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| 167 | if b >= len(count):
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| 168 | count = count + [0] * (b - len(count) + 1)
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| 169 | count[b] = count[b] + 1
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| 170 | b = 0
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| 171 | else:
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| 172 | break
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| 173 | self.n = n
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| 174 | self.nt = nt
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| 175 | self.norm = tuple(count), b
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| 176 | self.is_simple = len(count) <= 1
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| 177 |
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| 178 | # return length of longest contiguous run of spaces (whether or not
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| 179 | # preceding a tab)
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| 180 | def longest_run_of_spaces(self):
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| 181 | count, trailing = self.norm
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| 182 | return max(len(count)-1, trailing)
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| 183 |
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| 184 | def indent_level(self, tabsize):
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| 185 | # count, il = self.norm
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| 186 | # for i in range(len(count)):
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| 187 | # if count[i]:
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| 188 | # il = il + (i/tabsize + 1)*tabsize * count[i]
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| 189 | # return il
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| 190 |
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| 191 | # quicker:
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| 192 | # il = trailing + sum (i/ts + 1)*ts*count[i] =
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| 193 | # trailing + ts * sum (i/ts + 1)*count[i] =
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| 194 | # trailing + ts * sum i/ts*count[i] + count[i] =
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| 195 | # trailing + ts * [(sum i/ts*count[i]) + (sum count[i])] =
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| 196 | # trailing + ts * [(sum i/ts*count[i]) + num_tabs]
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| 197 | # and note that i/ts*count[i] is 0 when i < ts
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| 198 |
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| 199 | count, trailing = self.norm
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| 200 | il = 0
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| 201 | for i in range(tabsize, len(count)):
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| 202 | il = il + i/tabsize * count[i]
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| 203 | return trailing + tabsize * (il + self.nt)
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| 204 |
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| 205 | # return true iff self.indent_level(t) == other.indent_level(t)
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| 206 | # for all t >= 1
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| 207 | def equal(self, other):
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| 208 | return self.norm == other.norm
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| 209 |
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| 210 | # return a list of tuples (ts, i1, i2) such that
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| 211 | # i1 == self.indent_level(ts) != other.indent_level(ts) == i2.
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| 212 | # Intended to be used after not self.equal(other) is known, in which
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| 213 | # case it will return at least one witnessing tab size.
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| 214 | def not_equal_witness(self, other):
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| 215 | n = max(self.longest_run_of_spaces(),
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| 216 | other.longest_run_of_spaces()) + 1
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| 217 | a = []
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| 218 | for ts in range(1, n+1):
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| 219 | if self.indent_level(ts) != other.indent_level(ts):
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| 220 | a.append( (ts,
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| 221 | self.indent_level(ts),
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| 222 | other.indent_level(ts)) )
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| 223 | return a
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| 224 |
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| 225 | # Return True iff self.indent_level(t) < other.indent_level(t)
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| 226 | # for all t >= 1.
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| 227 | # The algorithm is due to Vincent Broman.
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| 228 | # Easy to prove it's correct.
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| 229 | # XXXpost that.
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| 230 | # Trivial to prove n is sharp (consider T vs ST).
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| 231 | # Unknown whether there's a faster general way. I suspected so at
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| 232 | # first, but no longer.
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| 233 | # For the special (but common!) case where M and N are both of the
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| 234 | # form (T*)(S*), M.less(N) iff M.len() < N.len() and
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| 235 | # M.num_tabs() <= N.num_tabs(). Proof is easy but kinda long-winded.
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| 236 | # XXXwrite that up.
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| 237 | # Note that M is of the form (T*)(S*) iff len(M.norm[0]) <= 1.
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| 238 | def less(self, other):
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| 239 | if self.n >= other.n:
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| 240 | return False
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| 241 | if self.is_simple and other.is_simple:
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| 242 | return self.nt <= other.nt
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| 243 | n = max(self.longest_run_of_spaces(),
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| 244 | other.longest_run_of_spaces()) + 1
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| 245 | # the self.n >= other.n test already did it for ts=1
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| 246 | for ts in range(2, n+1):
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| 247 | if self.indent_level(ts) >= other.indent_level(ts):
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| 248 | return False
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| 249 | return True
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| 250 |
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| 251 | # return a list of tuples (ts, i1, i2) such that
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| 252 | # i1 == self.indent_level(ts) >= other.indent_level(ts) == i2.
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| 253 | # Intended to be used after not self.less(other) is known, in which
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| 254 | # case it will return at least one witnessing tab size.
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| 255 | def not_less_witness(self, other):
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| 256 | n = max(self.longest_run_of_spaces(),
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| 257 | other.longest_run_of_spaces()) + 1
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| 258 | a = []
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| 259 | for ts in range(1, n+1):
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| 260 | if self.indent_level(ts) >= other.indent_level(ts):
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| 261 | a.append( (ts,
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| 262 | self.indent_level(ts),
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| 263 | other.indent_level(ts)) )
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| 264 | return a
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| 265 |
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| 266 | def format_witnesses(w):
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| 267 | firsts = map(lambda tup: str(tup[0]), w)
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| 268 | prefix = "at tab size"
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| 269 | if len(w) > 1:
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| 270 | prefix = prefix + "s"
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| 271 | return prefix + " " + ', '.join(firsts)
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| 272 |
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| 273 | def process_tokens(tokens):
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| 274 | INDENT = tokenize.INDENT
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| 275 | DEDENT = tokenize.DEDENT
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| 276 | NEWLINE = tokenize.NEWLINE
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| 277 | JUNK = tokenize.COMMENT, tokenize.NL
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| 278 | indents = [Whitespace("")]
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| 279 | check_equal = 0
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| 280 |
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| 281 | for (type, token, start, end, line) in tokens:
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| 282 | if type == NEWLINE:
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| 283 | # a program statement, or ENDMARKER, will eventually follow,
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| 284 | # after some (possibly empty) run of tokens of the form
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| 285 | # (NL | COMMENT)* (INDENT | DEDENT+)?
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| 286 | # If an INDENT appears, setting check_equal is wrong, and will
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| 287 | # be undone when we see the INDENT.
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| 288 | check_equal = 1
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| 289 |
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| 290 | elif type == INDENT:
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| 291 | check_equal = 0
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| 292 | thisguy = Whitespace(token)
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| 293 | if not indents[-1].less(thisguy):
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| 294 | witness = indents[-1].not_less_witness(thisguy)
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| 295 | msg = "indent not greater e.g. " + format_witnesses(witness)
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| 296 | raise NannyNag(start[0], msg, line)
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| 297 | indents.append(thisguy)
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| 298 |
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| 299 | elif type == DEDENT:
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| 300 | # there's nothing we need to check here! what's important is
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| 301 | # that when the run of DEDENTs ends, the indentation of the
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| 302 | # program statement (or ENDMARKER) that triggered the run is
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| 303 | # equal to what's left at the top of the indents stack
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| 304 |
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| 305 | # Ouch! This assert triggers if the last line of the source
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| 306 | # is indented *and* lacks a newline -- then DEDENTs pop out
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| 307 | # of thin air.
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| 308 | # assert check_equal # else no earlier NEWLINE, or an earlier INDENT
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| 309 | check_equal = 1
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| 310 |
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| 311 | del indents[-1]
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| 312 |
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| 313 | elif check_equal and type not in JUNK:
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| 314 | # this is the first "real token" following a NEWLINE, so it
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| 315 | # must be the first token of the next program statement, or an
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| 316 | # ENDMARKER; the "line" argument exposes the leading whitespace
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| 317 | # for this statement; in the case of ENDMARKER, line is an empty
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| 318 | # string, so will properly match the empty string with which the
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| 319 | # "indents" stack was seeded
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| 320 | check_equal = 0
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| 321 | thisguy = Whitespace(line)
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| 322 | if not indents[-1].equal(thisguy):
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| 323 | witness = indents[-1].not_equal_witness(thisguy)
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| 324 | msg = "indent not equal e.g. " + format_witnesses(witness)
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| 325 | raise NannyNag(start[0], msg, line)
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| 326 |
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| 327 |
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| 328 | if __name__ == '__main__':
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| 329 | main()
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