feat(*): integrate revised mark approach ensuring backwards compatibility

also add test cases.

Author: sanjayaksaxena

src/automaton.js

@@ -259,17 +259,10 @@ var simpleFSM = function ( cache, token2Ignore ) {
     if ( terminalStates[ m0 ] === '0' ) return;
     // Not to be ignored — process it.
     var mark = markedStates[ m0 ];
-
     var customProperty = customPropertyAtStates[ m0 ];
     if ( mark ) {
-      // `match[ 1 ]` will now point to the index of the token where
-      // the entity should end because `match[ 0 ]` is pointing to the index
-      // of the token of detected entity's start and by adding `mark[ 1 ]`
-      // i.e. the `lastIndex` to it, we get the required value.
-      match[ 1 ] = match[ 0 ] + mark[ 1 ];
-      // For `match[ 0 ]`, simply adding `mark[ 0 ]` i.e. `firstIndex` yields
-      // the desried value.
       match[ 0 ] += mark[ 0 ];
+      match[ 1 ] -= mark[ 1 ];
     }
 
     // Removed `customProperty !== undefined &&` check while coding pos experiment

src/identify-marked-area.js

@@ -11,6 +11,11 @@ const identifyMarkedArea = function ( mark, length ) {
   lastIndex = Math.min( lastIndex, lm1 );
   if ( lastIndex < firstIndex ) lastIndex = lm1;
 
+  // The `lastIndex` manoeuvre is required to keep identical approach
+  // being followed in `learnSinglePattern()` of automaton.js, where
+  // the `firstIndex` **was** being added and the `lastIndex` **was** being
+  // subtracted from the span of entity.
+  lastIndex = length - lastIndex - 1;
   return [ firstIndex, lastIndex ];
 }; // identifyMarkedArea()
 

test/identify-marked-area-specs.js

@@ -0,0 +1,86 @@
+//     wink-nlp
+//
+//     Copyright (C) GRAYPE Systems Private Limited
+//
+//     This file is part of “wink-nlp”.
+//
+//     Permission is hereby granted, free of charge, to any
+//     person obtaining a copy of this software and
+//     associated documentation files (the "Software"), to
+//     deal in the Software without restriction, including
+//     without limitation the rights to use, copy, modify,
+//     merge, publish, distribute, sublicense, and/or sell
+//     copies of the Software, and to permit persons to
+//     whom the Software is furnished to do so, subject to
+//     the following conditions:
+//
+//     The above copyright notice and this permission notice
+//     shall be included in all copies or substantial
+//     portions of the Software.
+//
+//     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+//     ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+//     TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+//     PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+//     THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+//     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+//     CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+//     DEALINGS IN THE SOFTWARE.
+
+//
+
+var chai = require( 'chai' );
+var mocha = require( 'mocha' );
+var ima = require( '../src/identify-marked-area.js' );
+
+var expect = chai.expect;
+var describe = mocha.describe;
+var it = mocha.it;
+
+describe( 'Identify marked area', function () {
+  // Assume the entity length is 6 tokens and the area has
+  // to be decided by different values of `mark`. Note `mark`'s
+  // first & last indexes are 0 based when counting forward;
+  // and when counting backwards, `-1` refers to last and `-2`
+  // to last but one and so on.
+  const length = 6;
+
+  it( 'Left edge to right edge should return the entire area', function () {
+    // Counting forward.
+    // Note: the values in expect's comments are without the `lastIndex` manoeuvre to
+    // bring clarity in the test cases. Refer to the source file under test for details.
+    expect( ima( [ 0, 5 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+    // Counting backwards corresponding to the above.
+    expect( ima( [ -6, -1 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+    // Mix of backwards & forward.
+    expect( ima( [ -6, 5 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+    expect( ima( [ 0, -1 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+  } );
+
+  it( 'Single values at left edge, middle(2nd) & right edge should yield [0, 0], [2, 2], & [5, 5]', function () {
+    // Counting forward.
+    expect( ima( [ 0, 0 ], length ) ).deep.equals( [ 0, 5 ] ); // [ 0, 0 ]
+    expect( ima( [ 2, 2 ], length ) ).deep.equals( [ 2, 3 ] ); // [ 2, 2 ]
+    expect( ima( [ 5, 5 ], length ) ).deep.equals( [ 5, 0 ] ); // [ 5, 5 ]
+    // Counting backwards corresponding to the above.
+    expect( ima( [ -6, -6 ], length ) ).deep.equals( [ 0, 5 ] ); // [ 0, 0 ]
+    expect( ima( [ -4, -4 ], length ) ).deep.equals( [ 2, 3 ] ); // [ 2, 2 ]
+    expect( ima( [ -1, -1 ], length ) ).deep.equals( [ 5, 0 ] ); // [ 5, 5 ]
+    // Mix of backwards & forward.
+    expect( ima( [ -6, 0 ], length ) ).deep.equals( [ 0, 5 ] ); // [ 0, 0 ]
+    expect( ima( [ -4, 2 ], length ) ).deep.equals( [ 2, 3 ] ); // [ 2, 2 ]
+    expect( ima( [ 2, -4 ], length ) ).deep.equals( [ 2, 3 ] ); // [ 2, 2 ]
+    expect( ima( [ 5, -1 ], length ) ).deep.equals( [ 5, 0 ] ); // [ 5, 5 ]
+    expect( ima( [ -1, 5 ], length ) ).deep.equals( [ 5, 0 ] ); // [ 5, 5 ]
+  } );
+
+  it( 'Out of bound values should yield the entire area i.e. [0, 5]', function () {
+    // Counting forward beyond limits
+    expect( ima( [ 20, 500 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+    // Going backwards beyond limits
+    expect( ima( [ -10, 0 ], length ) ).deep.equals( [ 0, 5 ] ); // [ 0, 0 ]
+    expect( ima( [ -10, -1 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+    expect( ima( [ -10, -7 ], length ) ).deep.equals( [ 0, 0 ] ); // [ 0, 5 ]
+  } );
+} );