Class: Diff::LCS::DiffCallbacks
- Inherits:
-
Object
- Object
- Diff::LCS::DiffCallbacks
- Defined in:
- lib/diff/lcs/callbacks.rb
Overview
This will produce a compound array of simple diff change objects. Each element in the #diffs array is a hunk
or hunk
array, where each element in each hunk
array is a single Change object representing the addition or removal of a single element from one of the two tested sequences. The hunk
provides the full context for the changes.
diffs = Diff::LCS.diff(seq1, seq2)
# This example shows a simplified array format.
# [ [ [ '-', 0, 'a' ] ], # 1
# [ [ '+', 2, 'd' ] ], # 2
# [ [ '-', 4, 'h' ], # 3
# [ '+', 4, 'f' ] ],
# [ [ '+', 6, 'k' ] ], # 4
# [ [ '-', 8, 'n' ], # 5
# [ '-', 9, 'p' ],
# [ '+', 9, 'r' ],
# [ '+', 10, 's' ],
# [ '+', 11, 't' ] ] ]
There are five hunks here. The first hunk says that the a
at position 0 of the first sequence should be deleted ('-'
). The second hunk says that the d
at position 2 of the second sequence should be inserted ('+'
). The third hunk says that the h
at position 4 of the first sequence should be removed and replaced with the f
from position 4 of the second sequence. The other two hunks are described similarly.
Use
This callback object must be initialised and is used by the Diff::LCS#diff method.
cbo = Diff::LCS::DiffCallbacks.new
Diff::LCS.LCS(seq1, seq2, cbo)
cbo.finish
Note that the call to #finish is absolutely necessary, or the last set of changes will not be visible. Alternatively, can be used as:
cbo = Diff::LCS::DiffCallbacks.new { |tcbo| Diff::LCS.LCS(seq1, seq2, tcbo) }
The necessary #finish call will be made.
Simplified Array Format
The simplified array format used in the example above can be obtained with:
require 'pp'
pp diffs.map { |e| e.map { |f| f.to_a } }
Direct Known Subclasses
Instance Attribute Summary collapse
-
#diffs ⇒ Object
readonly
Returns the difference set collected during the diff process.
Instance Method Summary collapse
- #discard_a(event) ⇒ Object
- #discard_b(event) ⇒ Object
-
#finish ⇒ Object
Finalizes the diff process.
-
#initialize ⇒ DiffCallbacks
constructor
:yields: self.
- #match(_event) ⇒ Object
Constructor Details
#initialize ⇒ DiffCallbacks
:yields: self
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# File 'lib/diff/lcs/callbacks.rb', line 112 def initialize # :yields: self @hunk = [] @diffs = [] return unless block_given? begin yield self ensure finish end end |
Instance Attribute Details
#diffs ⇒ Object (readonly)
Returns the difference set collected during the diff process.
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# File 'lib/diff/lcs/callbacks.rb', line 110 def diffs @diffs end |
Instance Method Details
#discard_a(event) ⇒ Object
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# File 'lib/diff/lcs/callbacks.rb', line 135 def discard_a(event) @hunk << Diff::LCS::Change.new("-", event.old_position, event.old_element) end |
#discard_b(event) ⇒ Object
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# File 'lib/diff/lcs/callbacks.rb', line 139 def discard_b(event) @hunk << Diff::LCS::Change.new("+", event.new_position, event.new_element) end |
#finish ⇒ Object
Finalizes the diff process. If an unprocessed hunk still exists, then it is appended to the diff list.
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# File 'lib/diff/lcs/callbacks.rb', line 127 def finish finish_hunk end |
#match(_event) ⇒ Object
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# File 'lib/diff/lcs/callbacks.rb', line 131 def match(_event) finish_hunk end |