475 lines
12 KiB
Ruby
Executable File
475 lines
12 KiB
Ruby
Executable File
# heavily based off difflib.py - see that file for documentation
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# ported from Python by Bill Atkins
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# This does not support all features offered by difflib; it
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# implements only the subset of features necessary
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# to support a Ruby version of HTML Differ. You're welcome to finish this off.
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# By default, String#each iterates by line. This isn't really appropriate
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# for diff, so often a string will be split by // to get an array of one-
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# character strings.
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# Some methods in Diff are untested and are not guaranteed to work. The
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# methods in HTMLDiff and any methods it calls should work quite well.
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# changes by DenisMertz
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# * main change:
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# ** get the tag soup away
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# the tag soup problem was first reported with <p> tags, but it appeared also with
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# <li>, <ul> etc... tags
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# this version should mostly fix these problems
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# ** added a Builder class to manage the creation of the final htmldiff
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# * minor changes:
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# ** use symbols instead of string to represent opcodes
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# ** small fix to html2list
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#
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module Enumerable
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def reduce(init)
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result = init
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each { |item| result = yield(result, item) }
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result
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end
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end
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module Diff
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class SequenceMatcher
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def initialize(a=[''], b=[''], isjunk=nil, byline=false)
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a = (!byline and a.kind_of? String) ? a.split(//) : a
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b = (!byline and b.kind_of? String) ? b.split(//) : b
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@isjunk = isjunk || proc {}
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set_seqs a, b
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end
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def set_seqs(a, b)
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set_seq_a a
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set_seq_b b
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end
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def set_seq_a(a)
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@a = a
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@matching_blocks = @opcodes = nil
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end
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def set_seq_b(b)
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@b = b
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@matching_blocks = @opcodes = nil
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chain_b
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end
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def chain_b
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@fullbcount = nil
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@b2j = {}
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pophash = {}
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junkdict = {}
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@b.each_with_index do |elt, i|
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if @b2j.has_key? elt
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indices = @b2j[elt]
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if @b.length >= 200 and indices.length * 100 > @b.length
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pophash[elt] = 1
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indices.clear
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else
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indices.push i
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end
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else
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@b2j[elt] = [i]
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end
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end
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pophash.each_key { |elt| @b2j.delete elt }
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junkdict = {}
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unless @isjunk.nil?
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[pophash, @b2j].each do |d|
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d.each_key do |elt|
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if @isjunk.call(elt)
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junkdict[elt] = 1
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d.delete elt
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end
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end
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end
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end
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@isbjunk = junkdict.method(:has_key?)
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@isbpopular = junkdict.method(:has_key?)
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end
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def find_longest_match(alo, ahi, blo, bhi)
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besti, bestj, bestsize = alo, blo, 0
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j2len = {}
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(alo..ahi).step do |i|
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newj2len = {}
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(@b2j[@a[i]] || []).each do |j|
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if j < blo
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next
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end
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if j >= bhi
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break
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end
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k = newj2len[j] = (j2len[j - 1] || 0) + 1
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if k > bestsize
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besti, bestj, bestsize = i - k + 1, j - k + 1, k
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end
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end
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j2len = newj2len
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end
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while besti > alo and bestj > blo and
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not @isbjunk.call(@b[bestj-1]) and
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@a[besti-1] == @b[bestj-1]
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besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
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end
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while besti+bestsize < ahi and bestj+bestsize < bhi and
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not @isbjunk.call(@b[bestj+bestsize]) and
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@a[besti+bestsize] == @b[bestj+bestsize]
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bestsize += 1
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end
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while besti > alo and bestj > blo and
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@isbjunk.call(@b[bestj-1]) and
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@a[besti-1] == @b[bestj-1]
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besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
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end
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while besti+bestsize < ahi and bestj+bestsize < bhi and
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@isbjunk.call(@b[bestj+bestsize]) and
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@a[besti+bestsize] == @b[bestj+bestsize]
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bestsize += 1
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end
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[besti, bestj, bestsize]
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end
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def get_matching_blocks
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return @matching_blocks unless @matching_blocks.nil? or
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@matching_blocks.empty?
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@matching_blocks = []
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la, lb = @a.length, @b.length
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match_block_helper(0, la, 0, lb, @matching_blocks)
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@matching_blocks.push [la, lb, 0]
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end
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def match_block_helper(alo, ahi, blo, bhi, answer)
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i, j, k = x = find_longest_match(alo, ahi, blo, bhi)
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if not k.zero?
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if alo < i and blo < j
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match_block_helper(alo, i, blo, j, answer)
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end
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answer.push x
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if i + k < ahi and j + k < bhi
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match_block_helper(i + k, ahi, j + k, bhi, answer)
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end
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end
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end
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def get_opcodes
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unless @opcodes.nil? or @opcodes.empty?
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return @opcodes
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end
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i = j = 0
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@opcodes = answer = []
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get_matching_blocks.each do |ai, bj, size|
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tag = if i < ai and j < bj
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:replace
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elsif i < ai
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:delete
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elsif j < bj
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:insert
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end
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answer.push [tag, i, ai, j, bj] if tag
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i, j = ai + size, bj + size
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answer.push [:equal, ai, i, bj, j] unless size.zero?
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end
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return answer
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end
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# XXX: untested
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def get_grouped_opcodes(n=3)
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codes = get_opcodes
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if codes[0][0] == :equal
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tag, i1, i2, j1, j2 = codes[0]
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codes[0] = tag, [i1, i2 - n].max, i2, [j1, j2-n].max, j2
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end
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if codes[-1][0] == :equal
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tag, i1, i2, j1, j2 = codes[-1]
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codes[-1] = tag, i1, min(i2, i1+n), j1, min(j2, j1+n)
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end
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nn = n + n
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group = []
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codes.each do |tag, i1, i2, j1, j2|
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if tag == :equal and i2-i1 > nn
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group.push [tag, i1, [i2, i1 + n].min, j1, [j2, j1 + n].min]
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yield group
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group = []
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i1, j1 = [i1, i2-n].max, [j1, j2-n].max
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group.push [tag, i1, i2, j1 ,j2]
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end
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end
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if group and group.length != 1 and group[0][0] == :equal
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yield group
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end
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end
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def ratio
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matches = get_matching_blocks.reduce(0) do |sum, triple|
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sum + triple[-1]
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end
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Diff.calculate_ratio(matches, @a.length + @b.length)
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end
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def quick_ratio
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if @fullbcount.nil? or @fullbcount.empty?
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@fullbcount = {}
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@b.each do |elt|
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@fullbcount[elt] = (@fullbcount[elt] || 0) + 1
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end
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end
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avail = {}
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matches = 0
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@a.each do |elt|
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if avail.has_key? elt
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numb = avail[elt]
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else
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numb = @fullbcount[elt] || 0
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end
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avail[elt] = numb - 1
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if numb > 0
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matches += 1
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end
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end
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Diff.calculate_ratio matches, @a.length + @b.length
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end
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def real_quick_ratio
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la, lb = @a.length, @b.length
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Diff.calculate_ratio([la, lb].min, la + lb)
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end
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protected :chain_b, :match_block_helper
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end # end class SequenceMatcher
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def self.calculate_ratio(matches, length)
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return 1.0 if length.zero?
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2.0 * matches / length
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end
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# XXX: untested
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def self.get_close_matches(word, possibilities, n=3, cutoff=0.6)
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unless n > 0
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raise "n must be > 0: #{n}"
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end
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unless 0.0 <= cutoff and cutoff <= 1.0
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raise "cutoff must be in (0.0..1.0): #{cutoff}"
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end
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result = []
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s = SequenceMatcher.new
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s.set_seq_b word
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possibilities.each do |x|
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s.set_seq_a x
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if s.real_quick_ratio >= cutoff and
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s.quick_ratio >= cutoff and
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s.ratio >= cutoff
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result.push [s.ratio, x]
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end
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end
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unless result.nil? or result.empty?
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result.sort
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result.reverse!
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result = result[-n..-1]
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end
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result.collect { |score, x| x }
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end
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def self.count_leading(line, ch)
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i, n = 0, line.length
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while i < n and line[i].chr == ch
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i += 1
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end
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i
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end
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end
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module HTMLDiff
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include Diff
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class Builder
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VALID_METHODS = [:replace, :insert, :delete, :equal]
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def initialize(a, b)
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@a = a
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@b = b
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@content = []
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end
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def do_op(opcode)
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@opcode = opcode
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op = @opcode[0]
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VALID_METHODS.include?(op) or raise(NameError, "Invalid opcode #{op}")
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self.method(op).call
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end
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def result
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@content.join('')
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end
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#this methods have to be called via do_op(opcode) so that @opcode is set properly
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private
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def replace
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delete("diffmod")
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insert("diffmod")
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end
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def insert(tagclass="diffins")
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op_helper("ins", tagclass, @b[@opcode[3]...@opcode[4]])
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end
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def delete(tagclass="diffdel")
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op_helper("del", tagclass, @a[@opcode[1]...@opcode[2]])
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end
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def equal
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@content += @b[@opcode[3]...@opcode[4]]
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end
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# using this as op_helper would be equivalent to the first version of diff.rb by Bill Atkins
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def op_helper_simple(tagname, tagclass, to_add)
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@content << "<#{tagname} class=\"#{tagclass}\">"
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@content += to_add
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@content << "</#{tagname}>"
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end
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# this tries to put <p> tags or newline chars before the opening diff tags (<ins> or <del>)
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# or after the ending diff tags
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# as a result the diff tags should be the "more inside" possible.
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# this seems to work nice with html containing only paragraphs
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# but not sure it works if there are other tags (div, span ... ? ) around
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def op_helper(tagname, tagclass, to_add)
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@content << to_add.shift while ( HTMLDiff.is_newline(to_add.first) or
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HTMLDiff.is_p_close_tag(to_add.first) or
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HTMLDiff.is_p_open_tag(to_add.first) )
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@content << "<#{tagname} class=\"#{tagclass}\">"
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@content += to_add
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last_tags = []
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last_tags.unshift(@content.pop) while ( HTMLDiff.is_newline(@content.last) or
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HTMLDiff.is_p_close_tag(@content.last) or
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HTMLDiff.is_p_open_tag(@content.last) )
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last_tags.unshift "</#{tagname}>"
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@content += last_tags
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remove_empty_diff(tagname, tagclass)
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end
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def remove_empty_diff(tagname, tagclass)
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if @content[-2] == "<#{tagname} class=\"#{tagclass}\">" and @content[-1] == "</#{tagname}>" then
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@content.pop
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@content.pop
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end
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end
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end
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def self.is_newline(x)
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(x == "\n") or (x == "\r") or (x == "\t")
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end
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def self.is_p_open_tag(x)
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x =~ /\A<(p|li|ul|ol|dir|dt|dl)/
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end
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def self.is_p_close_tag(x)
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x =~ %r!\A</(p|li|ul|ol|dir|dt|dl)!
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end
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def self.diff(a, b)
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a, b = a.split(//), b.split(//) if a.kind_of? String and b.kind_of? String
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a, b = html2list(a), html2list(b)
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out = Builder.new(a, b)
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s = SequenceMatcher.new(a, b)
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s.get_opcodes.each do |opcode|
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out.do_op(opcode)
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end
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out.result
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end
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def self.html2list(x, b=false)
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mode = 'char'
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cur = ''
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out = []
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x = x.split(//) if x.kind_of? String
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x.each do |c|
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if mode == 'tag'
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if c == '>'
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if b
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cur += ']'
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else
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cur += c
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end
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out.push(cur)
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cur = ''
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mode = 'char'
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else
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cur += c
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end
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elsif mode == 'char'
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if c == '<'
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out.push cur
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if b
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cur = '['
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else
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cur = c
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end
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mode = 'tag'
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elsif /\s/.match c
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out.push cur + c
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cur = ''
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else
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cur += c
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end
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end
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end
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out.push cur
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# TODO: make something better here
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out.each{|x| x.chomp! unless is_newline(x)}
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out.find_all { |x| x != '' }
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end
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end
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if __FILE__ == $0
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require 'pp'
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# a = "<p>this is the original string</p>" # \n<p>but around the world</p>"
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# b = "<p>this is the original </p><p>other parag</p><p>string</p>"
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a = "<ul>\n\t<li>one</li>\n\t<li>two</li>\n</ul>"
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b = "<ul>\n\t<li>one</li>\n\t<li>two\n\t<ul><li>abc</li></ul></li>\n</ul>"
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puts a
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pp HTMLDiff.html2list(a)
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puts
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puts b
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pp HTMLDiff.html2list(b)
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puts
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puts HTMLDiff.diff(a, b)
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end |