feat(Phase A): expand decoder rules (vowel insert, neighbors), tie-break ranking, merge norm+best suggestions with DEBUG timing; add tests

Author: arnabwahid

AvroKeyboardController.m

@@ -60,9 +60,29 @@ - (void)findCurrentCandidates {
             if ([[NSUserDefaults standardUserDefaults] objectForKey:@"ForgivingTypingEnabled"]) {
                 BOOL enabled = [[NSUserDefaults standardUserDefaults] boolForKey:@"ForgivingTypingEnabled"];
                 if (enabled) {
-                    termForLookup = [RomanNormalizer normalize:termForLookup];
+                    CFAbsoluteTime t0 = CFAbsoluteTimeGetCurrent();
+                    NSString *norm = [RomanNormalizer normalize:termForLookup];
                     // Choose best tolerant correction (includes original)
-                    termForLookup = [TolerantDecoder bestFor:termForLookup];
+                    NSString *best = [TolerantDecoder bestFor:norm];
+                    // Optionally, merge original+best lookups for broader suggestions
+                    if ([best isEqualToString:norm]) {
+                        termForLookup = best;
+                        #ifdef DEBUG
+                        NSLog(@"[FT] norm/best=%@ (%.2f ms)", best, (CFAbsoluteTimeGetCurrent()-t0)*1000.0);
+                        #endif
+                    } else {
+                        NSMutableOrderedSet *merged = [NSMutableOrderedSet orderedSet];
+                        NSArray *a = [[Suggestion sharedInstance] getList:norm];
+                        NSArray *b = [[Suggestion sharedInstance] getList:best];
+                        if (a) [merged addObjectsFromArray:a];
+                        if (b) [merged addObjectsFromArray:b];
+                        [_currentCandidates release];
+                        _currentCandidates = [[merged array] mutableCopy];
+                        #ifdef DEBUG
+                        NSLog(@"[FT] norm=%@ best=%@ merged=%lu (%.2f ms)", norm, best, (unsigned long)[_currentCandidates count], (CFAbsoluteTimeGetCurrent()-t0)*1000.0);
+                        #endif
+                        return; // Already set _currentCandidates
+                    }
                 }
             }
             _currentCandidates = [[[Suggestion sharedInstance] getList:termForLookup] retain];

Ranking.m

@@ -15,9 +15,11 @@ @implementation Ranking
         NSUInteger db = [roman levenshteinDistanceTo:b];
         if (da < db) return NSOrderedAscending;
         if (da > db) return NSOrderedDescending;
+        // Tie-breakers: prefer exact input if present, then lexical
+        if ([a isEqualToString:roman] && ![b isEqualToString:roman]) return NSOrderedAscending;
+        if ([b isEqualToString:roman] && ![a isEqualToString:roman]) return NSOrderedDescending;
         return [a compare:b];
     }];
 }
 
 @end
-

Tests/TolerantDecoderTests.m

@@ -31,5 +31,17 @@ - (void)testRankingOrdersByEditDistance {
     XCTAssertEqualObjects(ranked.firstObject, @"teh");
 }
 
-@end
+- (void)testNeighborSubstitution {
+    // 'tezt' -> neighbor substitution z->s should allow 'test'
+    NSString *best = [TolerantDecoder bestFor:@"tezt"];
+    // Depending on distance, 'tezt' (d1) vs 'test' (d1) tie-break keeps input; ensure 'test' is in candidates
+    NSArray *c = [TolerantDecoder candidatesFor:@"tezt" max:10];
+    XCTAssertTrue([c containsObject:@"test"]);
+}
 
+- (void)testMissingVowelInsertion {
+    NSString *best = [TolerantDecoder bestFor:@"bng"]; // expect 'bang'
+    XCTAssertEqualObjects(best, @"bang");
+}
+
+@end

TolerantDecoder.m

@@ -27,7 +27,7 @@ @implementation TolerantDecoder
         }
     }
 
-    // Missing vowel insertion (insert 'a' between consonant clusters)
+    // Missing vowel insertion (insert a common vowel between consonant clusters)
     NSCharacterSet *vowels = [NSCharacterSet characterSetWithCharactersInString:@"aeiou"]; // lowercase expected
     for (NSUInteger i = 0; i <= len && out.count < MAX(2, maxCount); i++) {
         if (i > 0 && i < len) {
@@ -38,19 +38,25 @@ @implementation TolerantDecoder
                 continue;
             }
             if (![vowels characterIsMember:p] && ![vowels characterIsMember:c]) {
-                NSMutableString *m = [roman mutableCopy];
-                [m insertString:@"a" atIndex:i];
-                [out addObject:m];
+                // Try a small set of vowels; add until max reached
+                for (NSString *v in @[@"a", @"e"]) {
+                    NSMutableString *m = [roman mutableCopy];
+                    [m insertString:v atIndex:i];
+                    [out addObject:m];
+                    if (out.count >= maxCount && maxCount > 0) break;
+                }
             }
         }
     }
 
-    // Keyboard neighbor substitution (very small, safe map)
+    // Keyboard neighbor substitution (small, safe map)
     NSDictionary<NSString*, NSArray<NSString*>*> *near = @{
         @"t": @[@"r", @"y"],
         @"e": @[@"w", @"r"],
         @"h": @[@"g", @"j"],
         @"n": @[@"b", @"m"],
+        @"s": @[@"a", @"w", @"x", @"z"],
+        @"z": @[@"s", @"x"],
     };
     for (NSUInteger i = 0; i < len && out.count < MAX(3, maxCount); i++) {
         NSString *ch = [[roman substringWithRange:NSMakeRange(i, 1)] lowercaseString];
@@ -88,4 +94,3 @@ + (NSString *)bestFor:(NSString *)roman {
 }
 
 @end
-