Object
This will produce a simple array of diff change objects. Each element in the diffs array is a single ContextChange. In the set of diffs provided by SDiffCallbacks, both old and new objects will be presented for both changed <strong>and unchanged</strong> objects. nil will be substituted for a discarded object.
The diffset produced by this callback, when provided to Diff::LCS#sdiff, will compute and display the necessary components to show two sequences and their minimized differences side by side, just like the Unix utility sdiff.
same same before | after old < - - > new seq1 = %w(a b c e h j l m n p) seq2 = %w(b c d e f j k l m r s t) diffs = Diff::LCS.sdiff(seq1, seq2) # This example shows a simplified array format. # [ [ "-", [ 0, "a"], [ 0, nil ] ], # [ "=", [ 1, "b"], [ 0, "b" ] ], # [ "=", [ 2, "c"], [ 1, "c" ] ], # [ "+", [ 3, nil], [ 2, "d" ] ], # [ "=", [ 3, "e"], [ 3, "e" ] ], # [ "!", [ 4, "h"], [ 4, "f" ] ], # [ "=", [ 5, "j"], [ 5, "j" ] ], # [ "+", [ 6, nil], [ 6, "k" ] ], # [ "=", [ 6, "l"], [ 7, "l" ] ], # [ "=", [ 7, "m"], [ 8, "m" ] ], # [ "!", [ 8, "n"], [ 9, "r" ] ], # [ "!", [ 9, "p"], [ 10, "s" ] ], # [ "+", [ 10, nil], [ 11, "t" ] ] ]
The result of this operation is similar to that of Diff::LCS::ContextDiffCallbacks. They may be compared as:
s = Diff::LCS.sdiff(seq1, seq2).reject { |e| e.action == "=" } c = Diff::LCS.sdiff(seq1, seq2, Diff::LCS::ContextDiffCallbacks).flatten s == c # -> true
This callback object must be initialised and is used by the Diff::LCS#sdiff method.
cbo = Diff::LCS::SDiffCallbacks.new Diff::LCS.LCS(seq1, seq2, cbo)
As with the other initialisable callback objects, Diff::LCS::SDiffCallbacks can be initialised with a block. As there is no "fininishing" to be done, this has no effect on the state of the object.
cbo = Diff::LCS::SDiffCallbacks.new { |tcbo| Diff::LCS.LCS(seq1, seq2, tcbo) }
The simplified array format used in the example above can be obtained with:
require 'pp' pp diffs.map { |e| e.to_a }
# File lib/diff/lcs/callbacks.rb, line 319 def change(event) @diffs << Diff::LCS::ContextChange.simplify(event) end
# File lib/diff/lcs/callbacks.rb, line 311 def discard_a(event) @diffs << Diff::LCS::ContextChange.simplify(event) end
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