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327 lines
11 KiB
327 lines
11 KiB
#! /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: |
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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 "%s: 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("%s: I/O Error: %s" % (`file`, str(msg))) |
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return |
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if verbose > 1: |
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print "checking", `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("%s: Token Error: %s" % (`file`, str(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 "%s: *** Line %d: trouble in tab city! ***" % ( |
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`file`, badline) |
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print "offending line:", `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, `line` |
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return |
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if verbose: |
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print "%s: 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 0 |
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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 0 |
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return 1 |
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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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import string |
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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 + " " + string.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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