Chil combo fix

tests/initialization.c

@@ -155,7 +155,7 @@ START_TEST (initialize_using_lang_code_custom_symbols_dir)
   varnam *handle;
 	int exitcode;
 
-	// Copy a sample vst file to the temp
+	/* Copy a sample vst file to the temp */
   exitcode = system ("cp ../schemes/ml.vst /tmp");
 
 	varnam_set_symbols_dir("/tmp");

tests/transliteration.c

@@ -114,6 +114,24 @@ START_TEST (indic_digit_rendering)
 }
 END_TEST
 
+START_TEST (no_chil_combos)
+{
+    int rc;
+    vword* word;
+    varray *words;
+
+    /* If learnings has the word മലയാളം which ends with an anusvaram or chil, the output becomes incorrect when combination is added to it 
+     * Like മലയാളംോ
+     * https://github.com/varnamproject/libvarnam/issues/166 */
+
+    rc = varnam_transliterate (varnam_instance, "malayalamO", &words);
+    assert_success (rc);
+    ck_assert_int_eq (varray_length (words), 2);
+    word = varray_get (words, 0);
+    ck_assert_str_eq (word->text, "മലയാളമോ");
+}
+END_TEST
+
 TCase* get_transliteration_tests()
 {
     TCase* tcase = tcase_create("transliteration");
@@ -123,5 +141,6 @@ TCase* get_transliteration_tests()
     tcase_add_test (tcase, dependent_vowel_rendering);
     tcase_add_test (tcase, cancellation_character_should_force_independent_vowel_form);
     tcase_add_test (tcase, indic_digit_rendering);
+    tcase_add_test (tcase, no_chil_combos);
     return tcase;
 }

words-table.c

@@ -448,6 +448,26 @@ print_tokens_array(varray *tokens)
 
 }
 
+/* Replaces last chil letter token with its root consonant.
+ * ൽ with ല */
+varray*
+replace_last_chil(varray *tokens)
+{
+    varray *tmp;
+    vtoken *last_token;
+
+    tmp = varray_get (tokens, varray_length(tokens) - 1);
+    assert (tmp);
+    last_token = varray_get (tmp, varray_length(tmp) - 1);
+    assert (last_token);
+
+    if (strcmp(last_token->tag, "chill") == 0) {
+        strcpy(last_token->value1, last_token->value3);
+    }
+
+    return tokens;
+}
+
 /* This function learns all possibilities of writing the word and it's prefixes.
  * It finds cartesian product of the tokens passed in and process each product.
  * tokens will be a multidimensional array */
@@ -867,6 +887,16 @@ vwt_tokenize_pattern (varnam *handle, const char *pattern, varray *result)
         rc = vst_tokenize (handle, strbuf_to_s(match), VARNAM_TOKENIZER_VALUE, VARNAM_MATCH_EXACT, tokens);
         if (rc) return rc;
 
+        /**
+         * Suppose varnam learnings has the word `kilivaathil => കിളിവാതിൽ`.
+         * When Varanm finds this word, what it does is use the word plus tokenizes the rest of it. This gives chil combinations.
+         * Prevent this by replacing end chil with its root consonant.
+         * https://github.com/varnamproject/libvarnam/issues/166
+         */
+        if (strcmp(handle->internal->scheme_details->langCode, "ml") == 0) {
+            replace_last_chil(tokens);
+        }
+
         add_tokens (handle, tokens, result, first_match);
         varray_clear (tokens);
     }