--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-2.6.1/Lib/difflib.py Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,2023 @@
+#! /usr/bin/env python
+
+"""
+Module difflib -- helpers for computing deltas between objects.
+
+Function get_close_matches(word, possibilities, n=3, cutoff=0.6):
+ Use SequenceMatcher to return list of the best "good enough" matches.
+
+Function context_diff(a, b):
+ For two lists of strings, return a delta in context diff format.
+
+Function ndiff(a, b):
+ Return a delta: the difference between `a` and `b` (lists of strings).
+
+Function restore(delta, which):
+ Return one of the two sequences that generated an ndiff delta.
+
+Function unified_diff(a, b):
+ For two lists of strings, return a delta in unified diff format.
+
+Class SequenceMatcher:
+ A flexible class for comparing pairs of sequences of any type.
+
+Class Differ:
+ For producing human-readable deltas from sequences of lines of text.
+
+Class HtmlDiff:
+ For producing HTML side by side comparison with change highlights.
+"""
+
+__all__ = ['get_close_matches', 'ndiff', 'restore', 'SequenceMatcher',
+ 'Differ','IS_CHARACTER_JUNK', 'IS_LINE_JUNK', 'context_diff',
+ 'unified_diff', 'HtmlDiff', 'Match']
+
+import heapq
+from collections import namedtuple as _namedtuple
+from functools import reduce
+
+Match = _namedtuple('Match', 'a b size')
+
+def _calculate_ratio(matches, length):
+ if length:
+ return 2.0 * matches / length
+ return 1.0
+
+class SequenceMatcher:
+
+ """
+ SequenceMatcher is a flexible class for comparing pairs of sequences of
+ any type, so long as the sequence elements are hashable. The basic
+ algorithm predates, and is a little fancier than, an algorithm
+ published in the late 1980's by Ratcliff and Obershelp under the
+ hyperbolic name "gestalt pattern matching". The basic idea is to find
+ the longest contiguous matching subsequence that contains no "junk"
+ elements (R-O doesn't address junk). The same idea is then applied
+ recursively to the pieces of the sequences to the left and to the right
+ of the matching subsequence. This does not yield minimal edit
+ sequences, but does tend to yield matches that "look right" to people.
+
+ SequenceMatcher tries to compute a "human-friendly diff" between two
+ sequences. Unlike e.g. UNIX(tm) diff, the fundamental notion is the
+ longest *contiguous* & junk-free matching subsequence. That's what
+ catches peoples' eyes. The Windows(tm) windiff has another interesting
+ notion, pairing up elements that appear uniquely in each sequence.
+ That, and the method here, appear to yield more intuitive difference
+ reports than does diff. This method appears to be the least vulnerable
+ to synching up on blocks of "junk lines", though (like blank lines in
+ ordinary text files, or maybe "<P>" lines in HTML files). That may be
+ because this is the only method of the 3 that has a *concept* of
+ "junk" <wink>.
+
+ Example, comparing two strings, and considering blanks to be "junk":
+
+ >>> s = SequenceMatcher(lambda x: x == " ",
+ ... "private Thread currentThread;",
+ ... "private volatile Thread currentThread;")
+ >>>
+
+ .ratio() returns a float in [0, 1], measuring the "similarity" of the
+ sequences. As a rule of thumb, a .ratio() value over 0.6 means the
+ sequences are close matches:
+
+ >>> print round(s.ratio(), 3)
+ 0.866
+ >>>
+
+ If you're only interested in where the sequences match,
+ .get_matching_blocks() is handy:
+
+ >>> for block in s.get_matching_blocks():
+ ... print "a[%d] and b[%d] match for %d elements" % block
+ a[0] and b[0] match for 8 elements
+ a[8] and b[17] match for 21 elements
+ a[29] and b[38] match for 0 elements
+
+ Note that the last tuple returned by .get_matching_blocks() is always a
+ dummy, (len(a), len(b), 0), and this is the only case in which the last
+ tuple element (number of elements matched) is 0.
+
+ If you want to know how to change the first sequence into the second,
+ use .get_opcodes():
+
+ >>> for opcode in s.get_opcodes():
+ ... print "%6s a[%d:%d] b[%d:%d]" % opcode
+ equal a[0:8] b[0:8]
+ insert a[8:8] b[8:17]
+ equal a[8:29] b[17:38]
+
+ See the Differ class for a fancy human-friendly file differencer, which
+ uses SequenceMatcher both to compare sequences of lines, and to compare
+ sequences of characters within similar (near-matching) lines.
+
+ See also function get_close_matches() in this module, which shows how
+ simple code building on SequenceMatcher can be used to do useful work.
+
+ Timing: Basic R-O is cubic time worst case and quadratic time expected
+ case. SequenceMatcher is quadratic time for the worst case and has
+ expected-case behavior dependent in a complicated way on how many
+ elements the sequences have in common; best case time is linear.
+
+ Methods:
+
+ __init__(isjunk=None, a='', b='')
+ Construct a SequenceMatcher.
+
+ set_seqs(a, b)
+ Set the two sequences to be compared.
+
+ set_seq1(a)
+ Set the first sequence to be compared.
+
+ set_seq2(b)
+ Set the second sequence to be compared.
+
+ find_longest_match(alo, ahi, blo, bhi)
+ Find longest matching block in a[alo:ahi] and b[blo:bhi].
+
+ get_matching_blocks()
+ Return list of triples describing matching subsequences.
+
+ get_opcodes()
+ Return list of 5-tuples describing how to turn a into b.
+
+ ratio()
+ Return a measure of the sequences' similarity (float in [0,1]).
+
+ quick_ratio()
+ Return an upper bound on .ratio() relatively quickly.
+
+ real_quick_ratio()
+ Return an upper bound on ratio() very quickly.
+ """
+
+ def __init__(self, isjunk=None, a='', b=''):
+ """Construct a SequenceMatcher.
+
+ Optional arg isjunk is None (the default), or a one-argument
+ function that takes a sequence element and returns true iff the
+ element is junk. None is equivalent to passing "lambda x: 0", i.e.
+ no elements are considered to be junk. For example, pass
+ lambda x: x in " \\t"
+ if you're comparing lines as sequences of characters, and don't
+ want to synch up on blanks or hard tabs.
+
+ Optional arg a is the first of two sequences to be compared. By
+ default, an empty string. The elements of a must be hashable. See
+ also .set_seqs() and .set_seq1().
+
+ Optional arg b is the second of two sequences to be compared. By
+ default, an empty string. The elements of b must be hashable. See
+ also .set_seqs() and .set_seq2().
+ """
+
+ # Members:
+ # a
+ # first sequence
+ # b
+ # second sequence; differences are computed as "what do
+ # we need to do to 'a' to change it into 'b'?"
+ # b2j
+ # for x in b, b2j[x] is a list of the indices (into b)
+ # at which x appears; junk elements do not appear
+ # fullbcount
+ # for x in b, fullbcount[x] == the number of times x
+ # appears in b; only materialized if really needed (used
+ # only for computing quick_ratio())
+ # matching_blocks
+ # a list of (i, j, k) triples, where a[i:i+k] == b[j:j+k];
+ # ascending & non-overlapping in i and in j; terminated by
+ # a dummy (len(a), len(b), 0) sentinel
+ # opcodes
+ # a list of (tag, i1, i2, j1, j2) tuples, where tag is
+ # one of
+ # 'replace' a[i1:i2] should be replaced by b[j1:j2]
+ # 'delete' a[i1:i2] should be deleted
+ # 'insert' b[j1:j2] should be inserted
+ # 'equal' a[i1:i2] == b[j1:j2]
+ # isjunk
+ # a user-supplied function taking a sequence element and
+ # returning true iff the element is "junk" -- this has
+ # subtle but helpful effects on the algorithm, which I'll
+ # get around to writing up someday <0.9 wink>.
+ # DON'T USE! Only __chain_b uses this. Use isbjunk.
+ # isbjunk
+ # for x in b, isbjunk(x) == isjunk(x) but much faster;
+ # it's really the __contains__ method of a hidden dict.
+ # DOES NOT WORK for x in a!
+ # isbpopular
+ # for x in b, isbpopular(x) is true iff b is reasonably long
+ # (at least 200 elements) and x accounts for more than 1% of
+ # its elements. DOES NOT WORK for x in a!
+
+ self.isjunk = isjunk
+ self.a = self.b = None
+ self.set_seqs(a, b)
+
+ def set_seqs(self, a, b):
+ """Set the two sequences to be compared.
+
+ >>> s = SequenceMatcher()
+ >>> s.set_seqs("abcd", "bcde")
+ >>> s.ratio()
+ 0.75
+ """
+
+ self.set_seq1(a)
+ self.set_seq2(b)
+
+ def set_seq1(self, a):
+ """Set the first sequence to be compared.
+
+ The second sequence to be compared is not changed.
+
+ >>> s = SequenceMatcher(None, "abcd", "bcde")
+ >>> s.ratio()
+ 0.75
+ >>> s.set_seq1("bcde")
+ >>> s.ratio()
+ 1.0
+ >>>
+
+ SequenceMatcher computes and caches detailed information about the
+ second sequence, so if you want to compare one sequence S against
+ many sequences, use .set_seq2(S) once and call .set_seq1(x)
+ repeatedly for each of the other sequences.
+
+ See also set_seqs() and set_seq2().
+ """
+
+ if a is self.a:
+ return
+ self.a = a
+ self.matching_blocks = self.opcodes = None
+
+ def set_seq2(self, b):
+ """Set the second sequence to be compared.
+
+ The first sequence to be compared is not changed.
+
+ >>> s = SequenceMatcher(None, "abcd", "bcde")
+ >>> s.ratio()
+ 0.75
+ >>> s.set_seq2("abcd")
+ >>> s.ratio()
+ 1.0
+ >>>
+
+ SequenceMatcher computes and caches detailed information about the
+ second sequence, so if you want to compare one sequence S against
+ many sequences, use .set_seq2(S) once and call .set_seq1(x)
+ repeatedly for each of the other sequences.
+
+ See also set_seqs() and set_seq1().
+ """
+
+ if b is self.b:
+ return
+ self.b = b
+ self.matching_blocks = self.opcodes = None
+ self.fullbcount = None
+ self.__chain_b()
+
+ # For each element x in b, set b2j[x] to a list of the indices in
+ # b where x appears; the indices are in increasing order; note that
+ # the number of times x appears in b is len(b2j[x]) ...
+ # when self.isjunk is defined, junk elements don't show up in this
+ # map at all, which stops the central find_longest_match method
+ # from starting any matching block at a junk element ...
+ # also creates the fast isbjunk function ...
+ # b2j also does not contain entries for "popular" elements, meaning
+ # elements that account for more than 1% of the total elements, and
+ # when the sequence is reasonably large (>= 200 elements); this can
+ # be viewed as an adaptive notion of semi-junk, and yields an enormous
+ # speedup when, e.g., comparing program files with hundreds of
+ # instances of "return NULL;" ...
+ # note that this is only called when b changes; so for cross-product
+ # kinds of matches, it's best to call set_seq2 once, then set_seq1
+ # repeatedly
+
+ def __chain_b(self):
+ # Because isjunk is a user-defined (not C) function, and we test
+ # for junk a LOT, it's important to minimize the number of calls.
+ # Before the tricks described here, __chain_b was by far the most
+ # time-consuming routine in the whole module! If anyone sees
+ # Jim Roskind, thank him again for profile.py -- I never would
+ # have guessed that.
+ # The first trick is to build b2j ignoring the possibility
+ # of junk. I.e., we don't call isjunk at all yet. Throwing
+ # out the junk later is much cheaper than building b2j "right"
+ # from the start.
+ b = self.b
+ n = len(b)
+ self.b2j = b2j = {}
+ populardict = {}
+ for i, elt in enumerate(b):
+ if elt in b2j:
+ indices = b2j[elt]
+ if n >= 200 and len(indices) * 100 > n:
+ populardict[elt] = 1
+ del indices[:]
+ else:
+ indices.append(i)
+ else:
+ b2j[elt] = [i]
+
+ # Purge leftover indices for popular elements.
+ for elt in populardict:
+ del b2j[elt]
+
+ # Now b2j.keys() contains elements uniquely, and especially when
+ # the sequence is a string, that's usually a good deal smaller
+ # than len(string). The difference is the number of isjunk calls
+ # saved.
+ isjunk = self.isjunk
+ junkdict = {}
+ if isjunk:
+ for d in populardict, b2j:
+ for elt in d.keys():
+ if isjunk(elt):
+ junkdict[elt] = 1
+ del d[elt]
+
+ # Now for x in b, isjunk(x) == x in junkdict, but the
+ # latter is much faster. Note too that while there may be a
+ # lot of junk in the sequence, the number of *unique* junk
+ # elements is probably small. So the memory burden of keeping
+ # this dict alive is likely trivial compared to the size of b2j.
+ self.isbjunk = junkdict.__contains__
+ self.isbpopular = populardict.__contains__
+
+ def find_longest_match(self, alo, ahi, blo, bhi):
+ """Find longest matching block in a[alo:ahi] and b[blo:bhi].
+
+ If isjunk is not defined:
+
+ Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
+ alo <= i <= i+k <= ahi
+ blo <= j <= j+k <= bhi
+ and for all (i',j',k') meeting those conditions,
+ k >= k'
+ i <= i'
+ and if i == i', j <= j'
+
+ In other words, of all maximal matching blocks, return one that
+ starts earliest in a, and of all those maximal matching blocks that
+ start earliest in a, return the one that starts earliest in b.
+
+ >>> s = SequenceMatcher(None, " abcd", "abcd abcd")
+ >>> s.find_longest_match(0, 5, 0, 9)
+ Match(a=0, b=4, size=5)
+
+ If isjunk is defined, first the longest matching block is
+ determined as above, but with the additional restriction that no
+ junk element appears in the block. Then that block is extended as
+ far as possible by matching (only) junk elements on both sides. So
+ the resulting block never matches on junk except as identical junk
+ happens to be adjacent to an "interesting" match.
+
+ Here's the same example as before, but considering blanks to be
+ junk. That prevents " abcd" from matching the " abcd" at the tail
+ end of the second sequence directly. Instead only the "abcd" can
+ match, and matches the leftmost "abcd" in the second sequence:
+
+ >>> s = SequenceMatcher(lambda x: x==" ", " abcd", "abcd abcd")
+ >>> s.find_longest_match(0, 5, 0, 9)
+ Match(a=1, b=0, size=4)
+
+ If no blocks match, return (alo, blo, 0).
+
+ >>> s = SequenceMatcher(None, "ab", "c")
+ >>> s.find_longest_match(0, 2, 0, 1)
+ Match(a=0, b=0, size=0)
+ """
+
+ # CAUTION: stripping common prefix or suffix would be incorrect.
+ # E.g.,
+ # ab
+ # acab
+ # Longest matching block is "ab", but if common prefix is
+ # stripped, it's "a" (tied with "b"). UNIX(tm) diff does so
+ # strip, so ends up claiming that ab is changed to acab by
+ # inserting "ca" in the middle. That's minimal but unintuitive:
+ # "it's obvious" that someone inserted "ac" at the front.
+ # Windiff ends up at the same place as diff, but by pairing up
+ # the unique 'b's and then matching the first two 'a's.
+
+ a, b, b2j, isbjunk = self.a, self.b, self.b2j, self.isbjunk
+ besti, bestj, bestsize = alo, blo, 0
+ # find longest junk-free match
+ # during an iteration of the loop, j2len[j] = length of longest
+ # junk-free match ending with a[i-1] and b[j]
+ j2len = {}
+ nothing = []
+ for i in xrange(alo, ahi):
+ # look at all instances of a[i] in b; note that because
+ # b2j has no junk keys, the loop is skipped if a[i] is junk
+ j2lenget = j2len.get
+ newj2len = {}
+ for j in b2j.get(a[i], nothing):
+ # a[i] matches b[j]
+ if j < blo:
+ continue
+ if j >= bhi:
+ break
+ k = newj2len[j] = j2lenget(j-1, 0) + 1
+ if k > bestsize:
+ besti, bestj, bestsize = i-k+1, j-k+1, k
+ j2len = newj2len
+
+ # Extend the best by non-junk elements on each end. In particular,
+ # "popular" non-junk elements aren't in b2j, which greatly speeds
+ # the inner loop above, but also means "the best" match so far
+ # doesn't contain any junk *or* popular non-junk elements.
+ while besti > alo and bestj > blo and \
+ not isbjunk(b[bestj-1]) and \
+ a[besti-1] == b[bestj-1]:
+ besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+ while besti+bestsize < ahi and bestj+bestsize < bhi and \
+ not isbjunk(b[bestj+bestsize]) and \
+ a[besti+bestsize] == b[bestj+bestsize]:
+ bestsize += 1
+
+ # Now that we have a wholly interesting match (albeit possibly
+ # empty!), we may as well suck up the matching junk on each
+ # side of it too. Can't think of a good reason not to, and it
+ # saves post-processing the (possibly considerable) expense of
+ # figuring out what to do with it. In the case of an empty
+ # interesting match, this is clearly the right thing to do,
+ # because no other kind of match is possible in the regions.
+ while besti > alo and bestj > blo and \
+ isbjunk(b[bestj-1]) and \
+ a[besti-1] == b[bestj-1]:
+ besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+ while besti+bestsize < ahi and bestj+bestsize < bhi and \
+ isbjunk(b[bestj+bestsize]) and \
+ a[besti+bestsize] == b[bestj+bestsize]:
+ bestsize = bestsize + 1
+
+ return Match(besti, bestj, bestsize)
+
+ def get_matching_blocks(self):
+ """Return list of triples describing matching subsequences.
+
+ Each triple is of the form (i, j, n), and means that
+ a[i:i+n] == b[j:j+n]. The triples are monotonically increasing in
+ i and in j. New in Python 2.5, it's also guaranteed that if
+ (i, j, n) and (i', j', n') are adjacent triples in the list, and
+ the second is not the last triple in the list, then i+n != i' or
+ j+n != j'. IOW, adjacent triples never describe adjacent equal
+ blocks.
+
+ The last triple is a dummy, (len(a), len(b), 0), and is the only
+ triple with n==0.
+
+ >>> s = SequenceMatcher(None, "abxcd", "abcd")
+ >>> s.get_matching_blocks()
+ [Match(a=0, b=0, size=2), Match(a=3, b=2, size=2), Match(a=5, b=4, size=0)]
+ """
+
+ if self.matching_blocks is not None:
+ return self.matching_blocks
+ la, lb = len(self.a), len(self.b)
+
+ # This is most naturally expressed as a recursive algorithm, but
+ # at least one user bumped into extreme use cases that exceeded
+ # the recursion limit on their box. So, now we maintain a list
+ # ('queue`) of blocks we still need to look at, and append partial
+ # results to `matching_blocks` in a loop; the matches are sorted
+ # at the end.
+ queue = [(0, la, 0, lb)]
+ matching_blocks = []
+ while queue:
+ alo, ahi, blo, bhi = queue.pop()
+ i, j, k = x = self.find_longest_match(alo, ahi, blo, bhi)
+ # a[alo:i] vs b[blo:j] unknown
+ # a[i:i+k] same as b[j:j+k]
+ # a[i+k:ahi] vs b[j+k:bhi] unknown
+ if k: # if k is 0, there was no matching block
+ matching_blocks.append(x)
+ if alo < i and blo < j:
+ queue.append((alo, i, blo, j))
+ if i+k < ahi and j+k < bhi:
+ queue.append((i+k, ahi, j+k, bhi))
+ matching_blocks.sort()
+
+ # It's possible that we have adjacent equal blocks in the
+ # matching_blocks list now. Starting with 2.5, this code was added
+ # to collapse them.
+ i1 = j1 = k1 = 0
+ non_adjacent = []
+ for i2, j2, k2 in matching_blocks:
+ # Is this block adjacent to i1, j1, k1?
+ if i1 + k1 == i2 and j1 + k1 == j2:
+ # Yes, so collapse them -- this just increases the length of
+ # the first block by the length of the second, and the first
+ # block so lengthened remains the block to compare against.
+ k1 += k2
+ else:
+ # Not adjacent. Remember the first block (k1==0 means it's
+ # the dummy we started with), and make the second block the
+ # new block to compare against.
+ if k1:
+ non_adjacent.append((i1, j1, k1))
+ i1, j1, k1 = i2, j2, k2
+ if k1:
+ non_adjacent.append((i1, j1, k1))
+
+ non_adjacent.append( (la, lb, 0) )
+ self.matching_blocks = non_adjacent
+ return map(Match._make, self.matching_blocks)
+
+ def get_opcodes(self):
+ """Return list of 5-tuples describing how to turn a into b.
+
+ Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple
+ has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
+ tuple preceding it, and likewise for j1 == the previous j2.
+
+ The tags are strings, with these meanings:
+
+ 'replace': a[i1:i2] should be replaced by b[j1:j2]
+ 'delete': a[i1:i2] should be deleted.
+ Note that j1==j2 in this case.
+ 'insert': b[j1:j2] should be inserted at a[i1:i1].
+ Note that i1==i2 in this case.
+ 'equal': a[i1:i2] == b[j1:j2]
+
+ >>> a = "qabxcd"
+ >>> b = "abycdf"
+ >>> s = SequenceMatcher(None, a, b)
+ >>> for tag, i1, i2, j1, j2 in s.get_opcodes():
+ ... print ("%7s a[%d:%d] (%s) b[%d:%d] (%s)" %
+ ... (tag, i1, i2, a[i1:i2], j1, j2, b[j1:j2]))
+ delete a[0:1] (q) b[0:0] ()
+ equal a[1:3] (ab) b[0:2] (ab)
+ replace a[3:4] (x) b[2:3] (y)
+ equal a[4:6] (cd) b[3:5] (cd)
+ insert a[6:6] () b[5:6] (f)
+ """
+
+ if self.opcodes is not None:
+ return self.opcodes
+ i = j = 0
+ self.opcodes = answer = []
+ for ai, bj, size in self.get_matching_blocks():
+ # invariant: we've pumped out correct diffs to change
+ # a[:i] into b[:j], and the next matching block is
+ # a[ai:ai+size] == b[bj:bj+size]. So we need to pump
+ # out a diff to change a[i:ai] into b[j:bj], pump out
+ # the matching block, and move (i,j) beyond the match
+ tag = ''
+ if i < ai and j < bj:
+ tag = 'replace'
+ elif i < ai:
+ tag = 'delete'
+ elif j < bj:
+ tag = 'insert'
+ if tag:
+ answer.append( (tag, i, ai, j, bj) )
+ i, j = ai+size, bj+size
+ # the list of matching blocks is terminated by a
+ # sentinel with size 0
+ if size:
+ answer.append( ('equal', ai, i, bj, j) )
+ return answer
+
+ def get_grouped_opcodes(self, n=3):
+ """ Isolate change clusters by eliminating ranges with no changes.
+
+ Return a generator of groups with upto n lines of context.
+ Each group is in the same format as returned by get_opcodes().
+
+ >>> from pprint import pprint
+ >>> a = map(str, range(1,40))
+ >>> b = a[:]
+ >>> b[8:8] = ['i'] # Make an insertion
+ >>> b[20] += 'x' # Make a replacement
+ >>> b[23:28] = [] # Make a deletion
+ >>> b[30] += 'y' # Make another replacement
+ >>> pprint(list(SequenceMatcher(None,a,b).get_grouped_opcodes()))
+ [[('equal', 5, 8, 5, 8), ('insert', 8, 8, 8, 9), ('equal', 8, 11, 9, 12)],
+ [('equal', 16, 19, 17, 20),
+ ('replace', 19, 20, 20, 21),
+ ('equal', 20, 22, 21, 23),
+ ('delete', 22, 27, 23, 23),
+ ('equal', 27, 30, 23, 26)],
+ [('equal', 31, 34, 27, 30),
+ ('replace', 34, 35, 30, 31),
+ ('equal', 35, 38, 31, 34)]]
+ """
+
+ codes = self.get_opcodes()
+ if not codes:
+ codes = [("equal", 0, 1, 0, 1)]
+ # Fixup leading and trailing groups if they show no changes.
+ if codes[0][0] == 'equal':
+ tag, i1, i2, j1, j2 = codes[0]
+ codes[0] = tag, max(i1, i2-n), i2, max(j1, j2-n), j2
+ if codes[-1][0] == 'equal':
+ tag, i1, i2, j1, j2 = codes[-1]
+ codes[-1] = tag, i1, min(i2, i1+n), j1, min(j2, j1+n)
+
+ nn = n + n
+ group = []
+ for tag, i1, i2, j1, j2 in codes:
+ # End the current group and start a new one whenever
+ # there is a large range with no changes.
+ if tag == 'equal' and i2-i1 > nn:
+ group.append((tag, i1, min(i2, i1+n), j1, min(j2, j1+n)))
+ yield group
+ group = []
+ i1, j1 = max(i1, i2-n), max(j1, j2-n)
+ group.append((tag, i1, i2, j1 ,j2))
+ if group and not (len(group)==1 and group[0][0] == 'equal'):
+ yield group
+
+ def ratio(self):
+ """Return a measure of the sequences' similarity (float in [0,1]).
+
+ Where T is the total number of elements in both sequences, and
+ M is the number of matches, this is 2.0*M / T.
+ Note that this is 1 if the sequences are identical, and 0 if
+ they have nothing in common.
+
+ .ratio() is expensive to compute if you haven't already computed
+ .get_matching_blocks() or .get_opcodes(), in which case you may
+ want to try .quick_ratio() or .real_quick_ratio() first to get an
+ upper bound.
+
+ >>> s = SequenceMatcher(None, "abcd", "bcde")
+ >>> s.ratio()
+ 0.75
+ >>> s.quick_ratio()
+ 0.75
+ >>> s.real_quick_ratio()
+ 1.0
+ """
+
+ matches = reduce(lambda sum, triple: sum + triple[-1],
+ self.get_matching_blocks(), 0)
+ return _calculate_ratio(matches, len(self.a) + len(self.b))
+
+ def quick_ratio(self):
+ """Return an upper bound on ratio() relatively quickly.
+
+ This isn't defined beyond that it is an upper bound on .ratio(), and
+ is faster to compute.
+ """
+
+ # viewing a and b as multisets, set matches to the cardinality
+ # of their intersection; this counts the number of matches
+ # without regard to order, so is clearly an upper bound
+ if self.fullbcount is None:
+ self.fullbcount = fullbcount = {}
+ for elt in self.b:
+ fullbcount[elt] = fullbcount.get(elt, 0) + 1
+ fullbcount = self.fullbcount
+ # avail[x] is the number of times x appears in 'b' less the
+ # number of times we've seen it in 'a' so far ... kinda
+ avail = {}
+ availhas, matches = avail.__contains__, 0
+ for elt in self.a:
+ if availhas(elt):
+ numb = avail[elt]
+ else:
+ numb = fullbcount.get(elt, 0)
+ avail[elt] = numb - 1
+ if numb > 0:
+ matches = matches + 1
+ return _calculate_ratio(matches, len(self.a) + len(self.b))
+
+ def real_quick_ratio(self):
+ """Return an upper bound on ratio() very quickly.
+
+ This isn't defined beyond that it is an upper bound on .ratio(), and
+ is faster to compute than either .ratio() or .quick_ratio().
+ """
+
+ la, lb = len(self.a), len(self.b)
+ # can't have more matches than the number of elements in the
+ # shorter sequence
+ return _calculate_ratio(min(la, lb), la + lb)
+
+def get_close_matches(word, possibilities, n=3, cutoff=0.6):
+ """Use SequenceMatcher to return list of the best "good enough" matches.
+
+ word is a sequence for which close matches are desired (typically a
+ string).
+
+ possibilities is a list of sequences against which to match word
+ (typically a list of strings).
+
+ Optional arg n (default 3) is the maximum number of close matches to
+ return. n must be > 0.
+
+ Optional arg cutoff (default 0.6) is a float in [0, 1]. Possibilities
+ that don't score at least that similar to word are ignored.
+
+ The best (no more than n) matches among the possibilities are returned
+ in a list, sorted by similarity score, most similar first.
+
+ >>> get_close_matches("appel", ["ape", "apple", "peach", "puppy"])
+ ['apple', 'ape']
+ >>> import keyword as _keyword
+ >>> get_close_matches("wheel", _keyword.kwlist)
+ ['while']
+ >>> get_close_matches("apple", _keyword.kwlist)
+ []
+ >>> get_close_matches("accept", _keyword.kwlist)
+ ['except']
+ """
+
+ if not n > 0:
+ raise ValueError("n must be > 0: %r" % (n,))
+ if not 0.0 <= cutoff <= 1.0:
+ raise ValueError("cutoff must be in [0.0, 1.0]: %r" % (cutoff,))
+ result = []
+ s = SequenceMatcher()
+ s.set_seq2(word)
+ for x in possibilities:
+ s.set_seq1(x)
+ if s.real_quick_ratio() >= cutoff and \
+ s.quick_ratio() >= cutoff and \
+ s.ratio() >= cutoff:
+ result.append((s.ratio(), x))
+
+ # Move the best scorers to head of list
+ result = heapq.nlargest(n, result)
+ # Strip scores for the best n matches
+ return [x for score, x in result]
+
+def _count_leading(line, ch):
+ """
+ Return number of `ch` characters at the start of `line`.
+
+ Example:
+
+ >>> _count_leading(' abc', ' ')
+ 3
+ """
+
+ i, n = 0, len(line)
+ while i < n and line[i] == ch:
+ i += 1
+ return i
+
+class Differ:
+ r"""
+ Differ is a class for comparing sequences of lines of text, and
+ producing human-readable differences or deltas. Differ uses
+ SequenceMatcher both to compare sequences of lines, and to compare
+ sequences of characters within similar (near-matching) lines.
+
+ Each line of a Differ delta begins with a two-letter code:
+
+ '- ' line unique to sequence 1
+ '+ ' line unique to sequence 2
+ ' ' line common to both sequences
+ '? ' line not present in either input sequence
+
+ Lines beginning with '? ' attempt to guide the eye to intraline
+ differences, and were not present in either input sequence. These lines
+ can be confusing if the sequences contain tab characters.
+
+ Note that Differ makes no claim to produce a *minimal* diff. To the
+ contrary, minimal diffs are often counter-intuitive, because they synch
+ up anywhere possible, sometimes accidental matches 100 pages apart.
+ Restricting synch points to contiguous matches preserves some notion of
+ locality, at the occasional cost of producing a longer diff.
+
+ Example: Comparing two texts.
+
+ First we set up the texts, sequences of individual single-line strings
+ ending with newlines (such sequences can also be obtained from the
+ `readlines()` method of file-like objects):
+
+ >>> text1 = ''' 1. Beautiful is better than ugly.
+ ... 2. Explicit is better than implicit.
+ ... 3. Simple is better than complex.
+ ... 4. Complex is better than complicated.
+ ... '''.splitlines(1)
+ >>> len(text1)
+ 4
+ >>> text1[0][-1]
+ '\n'
+ >>> text2 = ''' 1. Beautiful is better than ugly.
+ ... 3. Simple is better than complex.
+ ... 4. Complicated is better than complex.
+ ... 5. Flat is better than nested.
+ ... '''.splitlines(1)
+
+ Next we instantiate a Differ object:
+
+ >>> d = Differ()
+
+ Note that when instantiating a Differ object we may pass functions to
+ filter out line and character 'junk'. See Differ.__init__ for details.
+
+ Finally, we compare the two:
+
+ >>> result = list(d.compare(text1, text2))
+
+ 'result' is a list of strings, so let's pretty-print it:
+
+ >>> from pprint import pprint as _pprint
+ >>> _pprint(result)
+ [' 1. Beautiful is better than ugly.\n',
+ '- 2. Explicit is better than implicit.\n',
+ '- 3. Simple is better than complex.\n',
+ '+ 3. Simple is better than complex.\n',
+ '? ++\n',
+ '- 4. Complex is better than complicated.\n',
+ '? ^ ---- ^\n',
+ '+ 4. Complicated is better than complex.\n',
+ '? ++++ ^ ^\n',
+ '+ 5. Flat is better than nested.\n']
+
+ As a single multi-line string it looks like this:
+
+ >>> print ''.join(result),
+ 1. Beautiful is better than ugly.
+ - 2. Explicit is better than implicit.
+ - 3. Simple is better than complex.
+ + 3. Simple is better than complex.
+ ? ++
+ - 4. Complex is better than complicated.
+ ? ^ ---- ^
+ + 4. Complicated is better than complex.
+ ? ++++ ^ ^
+ + 5. Flat is better than nested.
+
+ Methods:
+
+ __init__(linejunk=None, charjunk=None)
+ Construct a text differencer, with optional filters.
+
+ compare(a, b)
+ Compare two sequences of lines; generate the resulting delta.
+ """
+
+ def __init__(self, linejunk=None, charjunk=None):
+ """
+ Construct a text differencer, with optional filters.
+
+ The two optional keyword parameters are for filter functions:
+
+ - `linejunk`: A function that should accept a single string argument,
+ and return true iff the string is junk. The module-level function
+ `IS_LINE_JUNK` may be used to filter out lines without visible
+ characters, except for at most one splat ('#'). It is recommended
+ to leave linejunk None; as of Python 2.3, the underlying
+ SequenceMatcher class has grown an adaptive notion of "noise" lines
+ that's better than any static definition the author has ever been
+ able to craft.
+
+ - `charjunk`: A function that should accept a string of length 1. The
+ module-level function `IS_CHARACTER_JUNK` may be used to filter out
+ whitespace characters (a blank or tab; **note**: bad idea to include
+ newline in this!). Use of IS_CHARACTER_JUNK is recommended.
+ """
+
+ self.linejunk = linejunk
+ self.charjunk = charjunk
+
+ def compare(self, a, b):
+ r"""
+ Compare two sequences of lines; generate the resulting delta.
+
+ Each sequence must contain individual single-line strings ending with
+ newlines. Such sequences can be obtained from the `readlines()` method
+ of file-like objects. The delta generated also consists of newline-
+ terminated strings, ready to be printed as-is via the writeline()
+ method of a file-like object.
+
+ Example:
+
+ >>> print ''.join(Differ().compare('one\ntwo\nthree\n'.splitlines(1),
+ ... 'ore\ntree\nemu\n'.splitlines(1))),
+ - one
+ ? ^
+ + ore
+ ? ^
+ - two
+ - three
+ ? -
+ + tree
+ + emu
+ """
+
+ cruncher = SequenceMatcher(self.linejunk, a, b)
+ for tag, alo, ahi, blo, bhi in cruncher.get_opcodes():
+ if tag == 'replace':
+ g = self._fancy_replace(a, alo, ahi, b, blo, bhi)
+ elif tag == 'delete':
+ g = self._dump('-', a, alo, ahi)
+ elif tag == 'insert':
+ g = self._dump('+', b, blo, bhi)
+ elif tag == 'equal':
+ g = self._dump(' ', a, alo, ahi)
+ else:
+ raise ValueError, 'unknown tag %r' % (tag,)
+
+ for line in g:
+ yield line
+
+ def _dump(self, tag, x, lo, hi):
+ """Generate comparison results for a same-tagged range."""
+ for i in xrange(lo, hi):
+ yield '%s %s' % (tag, x[i])
+
+ def _plain_replace(self, a, alo, ahi, b, blo, bhi):
+ assert alo < ahi and blo < bhi
+ # dump the shorter block first -- reduces the burden on short-term
+ # memory if the blocks are of very different sizes
+ if bhi - blo < ahi - alo:
+ first = self._dump('+', b, blo, bhi)
+ second = self._dump('-', a, alo, ahi)
+ else:
+ first = self._dump('-', a, alo, ahi)
+ second = self._dump('+', b, blo, bhi)
+
+ for g in first, second:
+ for line in g:
+ yield line
+
+ def _fancy_replace(self, a, alo, ahi, b, blo, bhi):
+ r"""
+ When replacing one block of lines with another, search the blocks
+ for *similar* lines; the best-matching pair (if any) is used as a
+ synch point, and intraline difference marking is done on the
+ similar pair. Lots of work, but often worth it.
+
+ Example:
+
+ >>> d = Differ()
+ >>> results = d._fancy_replace(['abcDefghiJkl\n'], 0, 1,
+ ... ['abcdefGhijkl\n'], 0, 1)
+ >>> print ''.join(results),
+ - abcDefghiJkl
+ ? ^ ^ ^
+ + abcdefGhijkl
+ ? ^ ^ ^
+ """
+
+ # don't synch up unless the lines have a similarity score of at
+ # least cutoff; best_ratio tracks the best score seen so far
+ best_ratio, cutoff = 0.74, 0.75
+ cruncher = SequenceMatcher(self.charjunk)
+ eqi, eqj = None, None # 1st indices of equal lines (if any)
+
+ # search for the pair that matches best without being identical
+ # (identical lines must be junk lines, & we don't want to synch up
+ # on junk -- unless we have to)
+ for j in xrange(blo, bhi):
+ bj = b[j]
+ cruncher.set_seq2(bj)
+ for i in xrange(alo, ahi):
+ ai = a[i]
+ if ai == bj:
+ if eqi is None:
+ eqi, eqj = i, j
+ continue
+ cruncher.set_seq1(ai)
+ # computing similarity is expensive, so use the quick
+ # upper bounds first -- have seen this speed up messy
+ # compares by a factor of 3.
+ # note that ratio() is only expensive to compute the first
+ # time it's called on a sequence pair; the expensive part
+ # of the computation is cached by cruncher
+ if cruncher.real_quick_ratio() > best_ratio and \
+ cruncher.quick_ratio() > best_ratio and \
+ cruncher.ratio() > best_ratio:
+ best_ratio, best_i, best_j = cruncher.ratio(), i, j
+ if best_ratio < cutoff:
+ # no non-identical "pretty close" pair
+ if eqi is None:
+ # no identical pair either -- treat it as a straight replace
+ for line in self._plain_replace(a, alo, ahi, b, blo, bhi):
+ yield line
+ return
+ # no close pair, but an identical pair -- synch up on that
+ best_i, best_j, best_ratio = eqi, eqj, 1.0
+ else:
+ # there's a close pair, so forget the identical pair (if any)
+ eqi = None
+
+ # a[best_i] very similar to b[best_j]; eqi is None iff they're not
+ # identical
+
+ # pump out diffs from before the synch point
+ for line in self._fancy_helper(a, alo, best_i, b, blo, best_j):
+ yield line
+
+ # do intraline marking on the synch pair
+ aelt, belt = a[best_i], b[best_j]
+ if eqi is None:
+ # pump out a '-', '?', '+', '?' quad for the synched lines
+ atags = btags = ""
+ cruncher.set_seqs(aelt, belt)
+ for tag, ai1, ai2, bj1, bj2 in cruncher.get_opcodes():
+ la, lb = ai2 - ai1, bj2 - bj1
+ if tag == 'replace':
+ atags += '^' * la
+ btags += '^' * lb
+ elif tag == 'delete':
+ atags += '-' * la
+ elif tag == 'insert':
+ btags += '+' * lb
+ elif tag == 'equal':
+ atags += ' ' * la
+ btags += ' ' * lb
+ else:
+ raise ValueError, 'unknown tag %r' % (tag,)
+ for line in self._qformat(aelt, belt, atags, btags):
+ yield line
+ else:
+ # the synch pair is identical
+ yield ' ' + aelt
+
+ # pump out diffs from after the synch point
+ for line in self._fancy_helper(a, best_i+1, ahi, b, best_j+1, bhi):
+ yield line
+
+ def _fancy_helper(self, a, alo, ahi, b, blo, bhi):
+ g = []
+ if alo < ahi:
+ if blo < bhi:
+ g = self._fancy_replace(a, alo, ahi, b, blo, bhi)
+ else:
+ g = self._dump('-', a, alo, ahi)
+ elif blo < bhi:
+ g = self._dump('+', b, blo, bhi)
+
+ for line in g:
+ yield line
+
+ def _qformat(self, aline, bline, atags, btags):
+ r"""
+ Format "?" output and deal with leading tabs.
+
+ Example:
+
+ >>> d = Differ()
+ >>> results = d._qformat('\tabcDefghiJkl\n', '\t\tabcdefGhijkl\n',
+ ... ' ^ ^ ^ ', '+ ^ ^ ^ ')
+ >>> for line in results: print repr(line)
+ ...
+ '- \tabcDefghiJkl\n'
+ '? \t ^ ^ ^\n'
+ '+ \t\tabcdefGhijkl\n'
+ '? \t ^ ^ ^\n'
+ """
+
+ # Can hurt, but will probably help most of the time.
+ common = min(_count_leading(aline, "\t"),
+ _count_leading(bline, "\t"))
+ common = min(common, _count_leading(atags[:common], " "))
+ atags = atags[common:].rstrip()
+ btags = btags[common:].rstrip()
+
+ yield "- " + aline
+ if atags:
+ yield "? %s%s\n" % ("\t" * common, atags)
+
+ yield "+ " + bline
+ if btags:
+ yield "? %s%s\n" % ("\t" * common, btags)
+
+# With respect to junk, an earlier version of ndiff simply refused to
+# *start* a match with a junk element. The result was cases like this:
+# before: private Thread currentThread;
+# after: private volatile Thread currentThread;
+# If you consider whitespace to be junk, the longest contiguous match
+# not starting with junk is "e Thread currentThread". So ndiff reported
+# that "e volatil" was inserted between the 't' and the 'e' in "private".
+# While an accurate view, to people that's absurd. The current version
+# looks for matching blocks that are entirely junk-free, then extends the
+# longest one of those as far as possible but only with matching junk.
+# So now "currentThread" is matched, then extended to suck up the
+# preceding blank; then "private" is matched, and extended to suck up the
+# following blank; then "Thread" is matched; and finally ndiff reports
+# that "volatile " was inserted before "Thread". The only quibble
+# remaining is that perhaps it was really the case that " volatile"
+# was inserted after "private". I can live with that <wink>.
+
+import re
+
+def IS_LINE_JUNK(line, pat=re.compile(r"\s*#?\s*$").match):
+ r"""
+ Return 1 for ignorable line: iff `line` is blank or contains a single '#'.
+
+ Examples:
+
+ >>> IS_LINE_JUNK('\n')
+ True
+ >>> IS_LINE_JUNK(' # \n')
+ True
+ >>> IS_LINE_JUNK('hello\n')
+ False
+ """
+
+ return pat(line) is not None
+
+def IS_CHARACTER_JUNK(ch, ws=" \t"):
+ r"""
+ Return 1 for ignorable character: iff `ch` is a space or tab.
+
+ Examples:
+
+ >>> IS_CHARACTER_JUNK(' ')
+ True
+ >>> IS_CHARACTER_JUNK('\t')
+ True
+ >>> IS_CHARACTER_JUNK('\n')
+ False
+ >>> IS_CHARACTER_JUNK('x')
+ False
+ """
+
+ return ch in ws
+
+
+def unified_diff(a, b, fromfile='', tofile='', fromfiledate='',
+ tofiledate='', n=3, lineterm='\n'):
+ r"""
+ Compare two sequences of lines; generate the delta as a unified diff.
+
+ Unified diffs are a compact way of showing line changes and a few
+ lines of context. The number of context lines is set by 'n' which
+ defaults to three.
+
+ By default, the diff control lines (those with ---, +++, or @@) are
+ created with a trailing newline. This is helpful so that inputs
+ created from file.readlines() result in diffs that are suitable for
+ file.writelines() since both the inputs and outputs have trailing
+ newlines.
+
+ For inputs that do not have trailing newlines, set the lineterm
+ argument to "" so that the output will be uniformly newline free.
+
+ The unidiff format normally has a header for filenames and modification
+ times. Any or all of these may be specified using strings for
+ 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'. The modification
+ times are normally expressed in the format returned by time.ctime().
+
+ Example:
+
+ >>> for line in unified_diff('one two three four'.split(),
+ ... 'zero one tree four'.split(), 'Original', 'Current',
+ ... 'Sat Jan 26 23:30:50 1991', 'Fri Jun 06 10:20:52 2003',
+ ... lineterm=''):
+ ... print line
+ --- Original Sat Jan 26 23:30:50 1991
+ +++ Current Fri Jun 06 10:20:52 2003
+ @@ -1,4 +1,4 @@
+ +zero
+ one
+ -two
+ -three
+ +tree
+ four
+ """
+
+ started = False
+ for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
+ if not started:
+ yield '--- %s %s%s' % (fromfile, fromfiledate, lineterm)
+ yield '+++ %s %s%s' % (tofile, tofiledate, lineterm)
+ started = True
+ i1, i2, j1, j2 = group[0][1], group[-1][2], group[0][3], group[-1][4]
+ yield "@@ -%d,%d +%d,%d @@%s" % (i1+1, i2-i1, j1+1, j2-j1, lineterm)
+ for tag, i1, i2, j1, j2 in group:
+ if tag == 'equal':
+ for line in a[i1:i2]:
+ yield ' ' + line
+ continue
+ if tag == 'replace' or tag == 'delete':
+ for line in a[i1:i2]:
+ yield '-' + line
+ if tag == 'replace' or tag == 'insert':
+ for line in b[j1:j2]:
+ yield '+' + line
+
+# See http://www.unix.org/single_unix_specification/
+def context_diff(a, b, fromfile='', tofile='',
+ fromfiledate='', tofiledate='', n=3, lineterm='\n'):
+ r"""
+ Compare two sequences of lines; generate the delta as a context diff.
+
+ Context diffs are a compact way of showing line changes and a few
+ lines of context. The number of context lines is set by 'n' which
+ defaults to three.
+
+ By default, the diff control lines (those with *** or ---) are
+ created with a trailing newline. This is helpful so that inputs
+ created from file.readlines() result in diffs that are suitable for
+ file.writelines() since both the inputs and outputs have trailing
+ newlines.
+
+ For inputs that do not have trailing newlines, set the lineterm
+ argument to "" so that the output will be uniformly newline free.
+
+ The context diff format normally has a header for filenames and
+ modification times. Any or all of these may be specified using
+ strings for 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
+ The modification times are normally expressed in the format returned
+ by time.ctime(). If not specified, the strings default to blanks.
+
+ Example:
+
+ >>> print ''.join(context_diff('one\ntwo\nthree\nfour\n'.splitlines(1),
+ ... 'zero\none\ntree\nfour\n'.splitlines(1), 'Original', 'Current',
+ ... 'Sat Jan 26 23:30:50 1991', 'Fri Jun 06 10:22:46 2003')),
+ *** Original Sat Jan 26 23:30:50 1991
+ --- Current Fri Jun 06 10:22:46 2003
+ ***************
+ *** 1,4 ****
+ one
+ ! two
+ ! three
+ four
+ --- 1,4 ----
+ + zero
+ one
+ ! tree
+ four
+ """
+
+ started = False
+ prefixmap = {'insert':'+ ', 'delete':'- ', 'replace':'! ', 'equal':' '}
+ for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
+ if not started:
+ yield '*** %s %s%s' % (fromfile, fromfiledate, lineterm)
+ yield '--- %s %s%s' % (tofile, tofiledate, lineterm)
+ started = True
+
+ yield '***************%s' % (lineterm,)
+ if group[-1][2] - group[0][1] >= 2:
+ yield '*** %d,%d ****%s' % (group[0][1]+1, group[-1][2], lineterm)
+ else:
+ yield '*** %d ****%s' % (group[-1][2], lineterm)
+ visiblechanges = [e for e in group if e[0] in ('replace', 'delete')]
+ if visiblechanges:
+ for tag, i1, i2, _, _ in group:
+ if tag != 'insert':
+ for line in a[i1:i2]:
+ yield prefixmap[tag] + line
+
+ if group[-1][4] - group[0][3] >= 2:
+ yield '--- %d,%d ----%s' % (group[0][3]+1, group[-1][4], lineterm)
+ else:
+ yield '--- %d ----%s' % (group[-1][4], lineterm)
+ visiblechanges = [e for e in group if e[0] in ('replace', 'insert')]
+ if visiblechanges:
+ for tag, _, _, j1, j2 in group:
+ if tag != 'delete':
+ for line in b[j1:j2]:
+ yield prefixmap[tag] + line
+
+def ndiff(a, b, linejunk=None, charjunk=IS_CHARACTER_JUNK):
+ r"""
+ Compare `a` and `b` (lists of strings); return a `Differ`-style delta.
+
+ Optional keyword parameters `linejunk` and `charjunk` are for filter
+ functions (or None):
+
+ - linejunk: A function that should accept a single string argument, and
+ return true iff the string is junk. The default is None, and is
+ recommended; as of Python 2.3, an adaptive notion of "noise" lines is
+ used that does a good job on its own.
+
+ - charjunk: A function that should accept a string of length 1. The
+ default is module-level function IS_CHARACTER_JUNK, which filters out
+ whitespace characters (a blank or tab; note: bad idea to include newline
+ in this!).
+
+ Tools/scripts/ndiff.py is a command-line front-end to this function.
+
+ Example:
+
+ >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(1),
+ ... 'ore\ntree\nemu\n'.splitlines(1))
+ >>> print ''.join(diff),
+ - one
+ ? ^
+ + ore
+ ? ^
+ - two
+ - three
+ ? -
+ + tree
+ + emu
+ """
+ return Differ(linejunk, charjunk).compare(a, b)
+
+def _mdiff(fromlines, tolines, context=None, linejunk=None,
+ charjunk=IS_CHARACTER_JUNK):
+ r"""Returns generator yielding marked up from/to side by side differences.
+
+ Arguments:
+ fromlines -- list of text lines to compared to tolines
+ tolines -- list of text lines to be compared to fromlines
+ context -- number of context lines to display on each side of difference,
+ if None, all from/to text lines will be generated.
+ linejunk -- passed on to ndiff (see ndiff documentation)
+ charjunk -- passed on to ndiff (see ndiff documentation)
+
+ This function returns an interator which returns a tuple:
+ (from line tuple, to line tuple, boolean flag)
+
+ from/to line tuple -- (line num, line text)
+ line num -- integer or None (to indicate a context seperation)
+ line text -- original line text with following markers inserted:
+ '\0+' -- marks start of added text
+ '\0-' -- marks start of deleted text
+ '\0^' -- marks start of changed text
+ '\1' -- marks end of added/deleted/changed text
+
+ boolean flag -- None indicates context separation, True indicates
+ either "from" or "to" line contains a change, otherwise False.
+
+ This function/iterator was originally developed to generate side by side
+ file difference for making HTML pages (see HtmlDiff class for example
+ usage).
+
+ Note, this function utilizes the ndiff function to generate the side by
+ side difference markup. Optional ndiff arguments may be passed to this
+ function and they in turn will be passed to ndiff.
+ """
+ import re
+
+ # regular expression for finding intraline change indices
+ change_re = re.compile('(\++|\-+|\^+)')
+
+ # create the difference iterator to generate the differences
+ diff_lines_iterator = ndiff(fromlines,tolines,linejunk,charjunk)
+
+ def _make_line(lines, format_key, side, num_lines=[0,0]):
+ """Returns line of text with user's change markup and line formatting.
+
+ lines -- list of lines from the ndiff generator to produce a line of
+ text from. When producing the line of text to return, the
+ lines used are removed from this list.
+ format_key -- '+' return first line in list with "add" markup around
+ the entire line.
+ '-' return first line in list with "delete" markup around
+ the entire line.
+ '?' return first line in list with add/delete/change
+ intraline markup (indices obtained from second line)
+ None return first line in list with no markup
+ side -- indice into the num_lines list (0=from,1=to)
+ num_lines -- from/to current line number. This is NOT intended to be a
+ passed parameter. It is present as a keyword argument to
+ maintain memory of the current line numbers between calls
+ of this function.
+
+ Note, this function is purposefully not defined at the module scope so
+ that data it needs from its parent function (within whose context it
+ is defined) does not need to be of module scope.
+ """
+ num_lines[side] += 1
+ # Handle case where no user markup is to be added, just return line of
+ # text with user's line format to allow for usage of the line number.
+ if format_key is None:
+ return (num_lines[side],lines.pop(0)[2:])
+ # Handle case of intraline changes
+ if format_key == '?':
+ text, markers = lines.pop(0), lines.pop(0)
+ # find intraline changes (store change type and indices in tuples)
+ sub_info = []
+ def record_sub_info(match_object,sub_info=sub_info):
+ sub_info.append([match_object.group(1)[0],match_object.span()])
+ return match_object.group(1)
+ change_re.sub(record_sub_info,markers)
+ # process each tuple inserting our special marks that won't be
+ # noticed by an xml/html escaper.
+ for key,(begin,end) in sub_info[::-1]:
+ text = text[0:begin]+'\0'+key+text[begin:end]+'\1'+text[end:]
+ text = text[2:]
+ # Handle case of add/delete entire line
+ else:
+ text = lines.pop(0)[2:]
+ # if line of text is just a newline, insert a space so there is
+ # something for the user to highlight and see.
+ if not text:
+ text = ' '
+ # insert marks that won't be noticed by an xml/html escaper.
+ text = '\0' + format_key + text + '\1'
+ # Return line of text, first allow user's line formatter to do its
+ # thing (such as adding the line number) then replace the special
+ # marks with what the user's change markup.
+ return (num_lines[side],text)
+
+ def _line_iterator():
+ """Yields from/to lines of text with a change indication.
+
+ This function is an iterator. It itself pulls lines from a
+ differencing iterator, processes them and yields them. When it can
+ it yields both a "from" and a "to" line, otherwise it will yield one
+ or the other. In addition to yielding the lines of from/to text, a
+ boolean flag is yielded to indicate if the text line(s) have
+ differences in them.
+
+ Note, this function is purposefully not defined at the module scope so
+ that data it needs from its parent function (within whose context it
+ is defined) does not need to be of module scope.
+ """
+ lines = []
+ num_blanks_pending, num_blanks_to_yield = 0, 0
+ while True:
+ # Load up next 4 lines so we can look ahead, create strings which
+ # are a concatenation of the first character of each of the 4 lines
+ # so we can do some very readable comparisons.
+ while len(lines) < 4:
+ try:
+ lines.append(diff_lines_iterator.next())
+ except StopIteration:
+ lines.append('X')
+ s = ''.join([line[0] for line in lines])
+ if s.startswith('X'):
+ # When no more lines, pump out any remaining blank lines so the
+ # corresponding add/delete lines get a matching blank line so
+ # all line pairs get yielded at the next level.
+ num_blanks_to_yield = num_blanks_pending
+ elif s.startswith('-?+?'):
+ # simple intraline change
+ yield _make_line(lines,'?',0), _make_line(lines,'?',1), True
+ continue
+ elif s.startswith('--++'):
+ # in delete block, add block coming: we do NOT want to get
+ # caught up on blank lines yet, just process the delete line
+ num_blanks_pending -= 1
+ yield _make_line(lines,'-',0), None, True
+ continue
+ elif s.startswith(('--?+', '--+', '- ')):
+ # in delete block and see a intraline change or unchanged line
+ # coming: yield the delete line and then blanks
+ from_line,to_line = _make_line(lines,'-',0), None
+ num_blanks_to_yield,num_blanks_pending = num_blanks_pending-1,0
+ elif s.startswith('-+?'):
+ # intraline change
+ yield _make_line(lines,None,0), _make_line(lines,'?',1), True
+ continue
+ elif s.startswith('-?+'):
+ # intraline change
+ yield _make_line(lines,'?',0), _make_line(lines,None,1), True
+ continue
+ elif s.startswith('-'):
+ # delete FROM line
+ num_blanks_pending -= 1
+ yield _make_line(lines,'-',0), None, True
+ continue
+ elif s.startswith('+--'):
+ # in add block, delete block coming: we do NOT want to get
+ # caught up on blank lines yet, just process the add line
+ num_blanks_pending += 1
+ yield None, _make_line(lines,'+',1), True
+ continue
+ elif s.startswith(('+ ', '+-')):
+ # will be leaving an add block: yield blanks then add line
+ from_line, to_line = None, _make_line(lines,'+',1)
+ num_blanks_to_yield,num_blanks_pending = num_blanks_pending+1,0
+ elif s.startswith('+'):
+ # inside an add block, yield the add line
+ num_blanks_pending += 1
+ yield None, _make_line(lines,'+',1), True
+ continue
+ elif s.startswith(' '):
+ # unchanged text, yield it to both sides
+ yield _make_line(lines[:],None,0),_make_line(lines,None,1),False
+ continue
+ # Catch up on the blank lines so when we yield the next from/to
+ # pair, they are lined up.
+ while(num_blanks_to_yield < 0):
+ num_blanks_to_yield += 1
+ yield None,('','\n'),True
+ while(num_blanks_to_yield > 0):
+ num_blanks_to_yield -= 1
+ yield ('','\n'),None,True
+ if s.startswith('X'):
+ raise StopIteration
+ else:
+ yield from_line,to_line,True
+
+ def _line_pair_iterator():
+ """Yields from/to lines of text with a change indication.
+
+ This function is an iterator. It itself pulls lines from the line
+ iterator. Its difference from that iterator is that this function
+ always yields a pair of from/to text lines (with the change
+ indication). If necessary it will collect single from/to lines
+ until it has a matching pair from/to pair to yield.
+
+ Note, this function is purposefully not defined at the module scope so
+ that data it needs from its parent function (within whose context it
+ is defined) does not need to be of module scope.
+ """
+ line_iterator = _line_iterator()
+ fromlines,tolines=[],[]
+ while True:
+ # Collecting lines of text until we have a from/to pair
+ while (len(fromlines)==0 or len(tolines)==0):
+ from_line, to_line, found_diff =line_iterator.next()
+ if from_line is not None:
+ fromlines.append((from_line,found_diff))
+ if to_line is not None:
+ tolines.append((to_line,found_diff))
+ # Once we have a pair, remove them from the collection and yield it
+ from_line, fromDiff = fromlines.pop(0)
+ to_line, to_diff = tolines.pop(0)
+ yield (from_line,to_line,fromDiff or to_diff)
+
+ # Handle case where user does not want context differencing, just yield
+ # them up without doing anything else with them.
+ line_pair_iterator = _line_pair_iterator()
+ if context is None:
+ while True:
+ yield line_pair_iterator.next()
+ # Handle case where user wants context differencing. We must do some
+ # storage of lines until we know for sure that they are to be yielded.
+ else:
+ context += 1
+ lines_to_write = 0
+ while True:
+ # Store lines up until we find a difference, note use of a
+ # circular queue because we only need to keep around what
+ # we need for context.
+ index, contextLines = 0, [None]*(context)
+ found_diff = False
+ while(found_diff is False):
+ from_line, to_line, found_diff = line_pair_iterator.next()
+ i = index % context
+ contextLines[i] = (from_line, to_line, found_diff)
+ index += 1
+ # Yield lines that we have collected so far, but first yield
+ # the user's separator.
+ if index > context:
+ yield None, None, None
+ lines_to_write = context
+ else:
+ lines_to_write = index
+ index = 0
+ while(lines_to_write):
+ i = index % context
+ index += 1
+ yield contextLines[i]
+ lines_to_write -= 1
+ # Now yield the context lines after the change
+ lines_to_write = context-1
+ while(lines_to_write):
+ from_line, to_line, found_diff = line_pair_iterator.next()
+ # If another change within the context, extend the context
+ if found_diff:
+ lines_to_write = context-1
+ else:
+ lines_to_write -= 1
+ yield from_line, to_line, found_diff
+
+
+_file_template = """
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+
+<html>
+
+<head>
+ <meta http-equiv="Content-Type"
+ content="text/html; charset=ISO-8859-1" />
+ <title></title>
+ <style type="text/css">%(styles)s
+ </style>
+</head>
+
+<body>
+ %(table)s%(legend)s
+</body>
+
+</html>"""
+
+_styles = """
+ table.diff {font-family:Courier; border:medium;}
+ .diff_header {background-color:#e0e0e0}
+ td.diff_header {text-align:right}
+ .diff_next {background-color:#c0c0c0}
+ .diff_add {background-color:#aaffaa}
+ .diff_chg {background-color:#ffff77}
+ .diff_sub {background-color:#ffaaaa}"""
+
+_table_template = """
+ <table class="diff" id="difflib_chg_%(prefix)s_top"
+ cellspacing="0" cellpadding="0" rules="groups" >
+ <colgroup></colgroup> <colgroup></colgroup> <colgroup></colgroup>
+ <colgroup></colgroup> <colgroup></colgroup> <colgroup></colgroup>
+ %(header_row)s
+ <tbody>
+%(data_rows)s </tbody>
+ </table>"""
+
+_legend = """
+ <table class="diff" summary="Legends">
+ <tr> <th colspan="2"> Legends </th> </tr>
+ <tr> <td> <table border="" summary="Colors">
+ <tr><th> Colors </th> </tr>
+ <tr><td class="diff_add"> Added </td></tr>
+ <tr><td class="diff_chg">Changed</td> </tr>
+ <tr><td class="diff_sub">Deleted</td> </tr>
+ </table></td>
+ <td> <table border="" summary="Links">
+ <tr><th colspan="2"> Links </th> </tr>
+ <tr><td>(f)irst change</td> </tr>
+ <tr><td>(n)ext change</td> </tr>
+ <tr><td>(t)op</td> </tr>
+ </table></td> </tr>
+ </table>"""
+
+class HtmlDiff(object):
+ """For producing HTML side by side comparison with change highlights.
+
+ This class can be used to create an HTML table (or a complete HTML file
+ containing the table) showing a side by side, line by line comparison
+ of text with inter-line and intra-line change highlights. The table can
+ be generated in either full or contextual difference mode.
+
+ The following methods are provided for HTML generation:
+
+ make_table -- generates HTML for a single side by side table
+ make_file -- generates complete HTML file with a single side by side table
+
+ See tools/scripts/diff.py for an example usage of this class.
+ """
+
+ _file_template = _file_template
+ _styles = _styles
+ _table_template = _table_template
+ _legend = _legend
+ _default_prefix = 0
+
+ def __init__(self,tabsize=8,wrapcolumn=None,linejunk=None,
+ charjunk=IS_CHARACTER_JUNK):
+ """HtmlDiff instance initializer
+
+ Arguments:
+ tabsize -- tab stop spacing, defaults to 8.
+ wrapcolumn -- column number where lines are broken and wrapped,
+ defaults to None where lines are not wrapped.
+ linejunk,charjunk -- keyword arguments passed into ndiff() (used to by
+ HtmlDiff() to generate the side by side HTML differences). See
+ ndiff() documentation for argument default values and descriptions.
+ """
+ self._tabsize = tabsize
+ self._wrapcolumn = wrapcolumn
+ self._linejunk = linejunk
+ self._charjunk = charjunk
+
+ def make_file(self,fromlines,tolines,fromdesc='',todesc='',context=False,
+ numlines=5):
+ """Returns HTML file of side by side comparison with change highlights
+
+ Arguments:
+ fromlines -- list of "from" lines
+ tolines -- list of "to" lines
+ fromdesc -- "from" file column header string
+ todesc -- "to" file column header string
+ context -- set to True for contextual differences (defaults to False
+ which shows full differences).
+ numlines -- number of context lines. When context is set True,
+ controls number of lines displayed before and after the change.
+ When context is False, controls the number of lines to place
+ the "next" link anchors before the next change (so click of
+ "next" link jumps to just before the change).
+ """
+
+ return self._file_template % dict(
+ styles = self._styles,
+ legend = self._legend,
+ table = self.make_table(fromlines,tolines,fromdesc,todesc,
+ context=context,numlines=numlines))
+
+ def _tab_newline_replace(self,fromlines,tolines):
+ """Returns from/to line lists with tabs expanded and newlines removed.
+
+ Instead of tab characters being replaced by the number of spaces
+ needed to fill in to the next tab stop, this function will fill
+ the space with tab characters. This is done so that the difference
+ algorithms can identify changes in a file when tabs are replaced by
+ spaces and vice versa. At the end of the HTML generation, the tab
+ characters will be replaced with a nonbreakable space.
+ """
+ def expand_tabs(line):
+ # hide real spaces
+ line = line.replace(' ','\0')
+ # expand tabs into spaces
+ line = line.expandtabs(self._tabsize)
+ # relace spaces from expanded tabs back into tab characters
+ # (we'll replace them with markup after we do differencing)
+ line = line.replace(' ','\t')
+ return line.replace('\0',' ').rstrip('\n')
+ fromlines = [expand_tabs(line) for line in fromlines]
+ tolines = [expand_tabs(line) for line in tolines]
+ return fromlines,tolines
+
+ def _split_line(self,data_list,line_num,text):
+ """Builds list of text lines by splitting text lines at wrap point
+
+ This function will determine if the input text line needs to be
+ wrapped (split) into separate lines. If so, the first wrap point
+ will be determined and the first line appended to the output
+ text line list. This function is used recursively to handle
+ the second part of the split line to further split it.
+ """
+ # if blank line or context separator, just add it to the output list
+ if not line_num:
+ data_list.append((line_num,text))
+ return
+
+ # if line text doesn't need wrapping, just add it to the output list
+ size = len(text)
+ max = self._wrapcolumn
+ if (size <= max) or ((size -(text.count('\0')*3)) <= max):
+ data_list.append((line_num,text))
+ return
+
+ # scan text looking for the wrap point, keeping track if the wrap
+ # point is inside markers
+ i = 0
+ n = 0
+ mark = ''
+ while n < max and i < size:
+ if text[i] == '\0':
+ i += 1
+ mark = text[i]
+ i += 1
+ elif text[i] == '\1':
+ i += 1
+ mark = ''
+ else:
+ i += 1
+ n += 1
+
+ # wrap point is inside text, break it up into separate lines
+ line1 = text[:i]
+ line2 = text[i:]
+
+ # if wrap point is inside markers, place end marker at end of first
+ # line and start marker at beginning of second line because each
+ # line will have its own table tag markup around it.
+ if mark:
+ line1 = line1 + '\1'
+ line2 = '\0' + mark + line2
+
+ # tack on first line onto the output list
+ data_list.append((line_num,line1))
+
+ # use this routine again to wrap the remaining text
+ self._split_line(data_list,'>',line2)
+
+ def _line_wrapper(self,diffs):
+ """Returns iterator that splits (wraps) mdiff text lines"""
+
+ # pull from/to data and flags from mdiff iterator
+ for fromdata,todata,flag in diffs:
+ # check for context separators and pass them through
+ if flag is None:
+ yield fromdata,todata,flag
+ continue
+ (fromline,fromtext),(toline,totext) = fromdata,todata
+ # for each from/to line split it at the wrap column to form
+ # list of text lines.
+ fromlist,tolist = [],[]
+ self._split_line(fromlist,fromline,fromtext)
+ self._split_line(tolist,toline,totext)
+ # yield from/to line in pairs inserting blank lines as
+ # necessary when one side has more wrapped lines
+ while fromlist or tolist:
+ if fromlist:
+ fromdata = fromlist.pop(0)
+ else:
+ fromdata = ('',' ')
+ if tolist:
+ todata = tolist.pop(0)
+ else:
+ todata = ('',' ')
+ yield fromdata,todata,flag
+
+ def _collect_lines(self,diffs):
+ """Collects mdiff output into separate lists
+
+ Before storing the mdiff from/to data into a list, it is converted
+ into a single line of text with HTML markup.
+ """
+
+ fromlist,tolist,flaglist = [],[],[]
+ # pull from/to data and flags from mdiff style iterator
+ for fromdata,todata,flag in diffs:
+ try:
+ # store HTML markup of the lines into the lists
+ fromlist.append(self._format_line(0,flag,*fromdata))
+ tolist.append(self._format_line(1,flag,*todata))
+ except TypeError:
+ # exceptions occur for lines where context separators go
+ fromlist.append(None)
+ tolist.append(None)
+ flaglist.append(flag)
+ return fromlist,tolist,flaglist
+
+ def _format_line(self,side,flag,linenum,text):
+ """Returns HTML markup of "from" / "to" text lines
+
+ side -- 0 or 1 indicating "from" or "to" text
+ flag -- indicates if difference on line
+ linenum -- line number (used for line number column)
+ text -- line text to be marked up
+ """
+ try:
+ linenum = '%d' % linenum
+ id = ' id="%s%s"' % (self._prefix[side],linenum)
+ except TypeError:
+ # handle blank lines where linenum is '>' or ''
+ id = ''
+ # replace those things that would get confused with HTML symbols
+ text=text.replace("&","&").replace(">",">").replace("<","<")
+
+ # make space non-breakable so they don't get compressed or line wrapped
+ text = text.replace(' ',' ').rstrip()
+
+ return '<td class="diff_header"%s>%s</td><td nowrap="nowrap">%s</td>' \
+ % (id,linenum,text)
+
+ def _make_prefix(self):
+ """Create unique anchor prefixes"""
+
+ # Generate a unique anchor prefix so multiple tables
+ # can exist on the same HTML page without conflicts.
+ fromprefix = "from%d_" % HtmlDiff._default_prefix
+ toprefix = "to%d_" % HtmlDiff._default_prefix
+ HtmlDiff._default_prefix += 1
+ # store prefixes so line format method has access
+ self._prefix = [fromprefix,toprefix]
+
+ def _convert_flags(self,fromlist,tolist,flaglist,context,numlines):
+ """Makes list of "next" links"""
+
+ # all anchor names will be generated using the unique "to" prefix
+ toprefix = self._prefix[1]
+
+ # process change flags, generating middle column of next anchors/links
+ next_id = ['']*len(flaglist)
+ next_href = ['']*len(flaglist)
+ num_chg, in_change = 0, False
+ last = 0
+ for i,flag in enumerate(flaglist):
+ if flag:
+ if not in_change:
+ in_change = True
+ last = i
+ # at the beginning of a change, drop an anchor a few lines
+ # (the context lines) before the change for the previous
+ # link
+ i = max([0,i-numlines])
+ next_id[i] = ' id="difflib_chg_%s_%d"' % (toprefix,num_chg)
+ # at the beginning of a change, drop a link to the next
+ # change
+ num_chg += 1
+ next_href[last] = '<a href="#difflib_chg_%s_%d">n</a>' % (
+ toprefix,num_chg)
+ else:
+ in_change = False
+ # check for cases where there is no content to avoid exceptions
+ if not flaglist:
+ flaglist = [False]
+ next_id = ['']
+ next_href = ['']
+ last = 0
+ if context:
+ fromlist = ['<td></td><td> No Differences Found </td>']
+ tolist = fromlist
+ else:
+ fromlist = tolist = ['<td></td><td> Empty File </td>']
+ # if not a change on first line, drop a link
+ if not flaglist[0]:
+ next_href[0] = '<a href="#difflib_chg_%s_0">f</a>' % toprefix
+ # redo the last link to link to the top
+ next_href[last] = '<a href="#difflib_chg_%s_top">t</a>' % (toprefix)
+
+ return fromlist,tolist,flaglist,next_href,next_id
+
+ def make_table(self,fromlines,tolines,fromdesc='',todesc='',context=False,
+ numlines=5):
+ """Returns HTML table of side by side comparison with change highlights
+
+ Arguments:
+ fromlines -- list of "from" lines
+ tolines -- list of "to" lines
+ fromdesc -- "from" file column header string
+ todesc -- "to" file column header string
+ context -- set to True for contextual differences (defaults to False
+ which shows full differences).
+ numlines -- number of context lines. When context is set True,
+ controls number of lines displayed before and after the change.
+ When context is False, controls the number of lines to place
+ the "next" link anchors before the next change (so click of
+ "next" link jumps to just before the change).
+ """
+
+ # make unique anchor prefixes so that multiple tables may exist
+ # on the same page without conflict.
+ self._make_prefix()
+
+ # change tabs to spaces before it gets more difficult after we insert
+ # markkup
+ fromlines,tolines = self._tab_newline_replace(fromlines,tolines)
+
+ # create diffs iterator which generates side by side from/to data
+ if context:
+ context_lines = numlines
+ else:
+ context_lines = None
+ diffs = _mdiff(fromlines,tolines,context_lines,linejunk=self._linejunk,
+ charjunk=self._charjunk)
+
+ # set up iterator to wrap lines that exceed desired width
+ if self._wrapcolumn:
+ diffs = self._line_wrapper(diffs)
+
+ # collect up from/to lines and flags into lists (also format the lines)
+ fromlist,tolist,flaglist = self._collect_lines(diffs)
+
+ # process change flags, generating middle column of next anchors/links
+ fromlist,tolist,flaglist,next_href,next_id = self._convert_flags(
+ fromlist,tolist,flaglist,context,numlines)
+
+ s = []
+ fmt = ' <tr><td class="diff_next"%s>%s</td>%s' + \
+ '<td class="diff_next">%s</td>%s</tr>\n'
+ for i in range(len(flaglist)):
+ if flaglist[i] is None:
+ # mdiff yields None on separator lines skip the bogus ones
+ # generated for the first line
+ if i > 0:
+ s.append(' </tbody> \n <tbody>\n')
+ else:
+ s.append( fmt % (next_id[i],next_href[i],fromlist[i],
+ next_href[i],tolist[i]))
+ if fromdesc or todesc:
+ header_row = '<thead><tr>%s%s%s%s</tr></thead>' % (
+ '<th class="diff_next"><br /></th>',
+ '<th colspan="2" class="diff_header">%s</th>' % fromdesc,
+ '<th class="diff_next"><br /></th>',
+ '<th colspan="2" class="diff_header">%s</th>' % todesc)
+ else:
+ header_row = ''
+
+ table = self._table_template % dict(
+ data_rows=''.join(s),
+ header_row=header_row,
+ prefix=self._prefix[1])
+
+ return table.replace('\0+','<span class="diff_add">'). \
+ replace('\0-','<span class="diff_sub">'). \
+ replace('\0^','<span class="diff_chg">'). \
+ replace('\1','</span>'). \
+ replace('\t',' ')
+
+del re
+
+def restore(delta, which):
+ r"""
+ Generate one of the two sequences that generated a delta.
+
+ Given a `delta` produced by `Differ.compare()` or `ndiff()`, extract
+ lines originating from file 1 or 2 (parameter `which`), stripping off line
+ prefixes.
+
+ Examples:
+
+ >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(1),
+ ... 'ore\ntree\nemu\n'.splitlines(1))
+ >>> diff = list(diff)
+ >>> print ''.join(restore(diff, 1)),
+ one
+ two
+ three
+ >>> print ''.join(restore(diff, 2)),
+ ore
+ tree
+ emu
+ """
+ try:
+ tag = {1: "- ", 2: "+ "}[int(which)]
+ except KeyError:
+ raise ValueError, ('unknown delta choice (must be 1 or 2): %r'
+ % which)
+ prefixes = (" ", tag)
+ for line in delta:
+ if line[:2] in prefixes:
+ yield line[2:]
+
+def _test():
+ import doctest, difflib
+ return doctest.testmod(difflib)
+
+if __name__ == "__main__":
+ _test()