implement syllable modifiers

iast.c

@@ -1,6 +1,13 @@
 #include <stdlib.h>
+#include <string.h>
 #include "iast.h"
 
+void diacritics_modifier_test(struct syllable *syllable)
+{
+	free(syllable->data);
+	syllable->data = strdup("X");
+}
+
 static const struct transliteration_letter table_letters[] = {
 
 	/* Vowels */
@@ -62,12 +69,18 @@ static const struct transliteration_letter table_letters[] = {
 	{0, NULL}
 };
 
+static const struct transliteration_modifier table_modifiers[] = {
+	{0x0940, diacritics_modifier_test},
+	{0, NULL}
+};
+
 struct transliteration_context *transliteration_context_iast_alloc()
 {
 	struct transliteration_context *context;
 
 	context = malloc(sizeof(*context));
 	context->table_letters = table_letters;
+	context->table_modifiers = table_modifiers;
 
 	return context;
 }

transliteration.c

@@ -5,10 +5,30 @@
 #include "syllable.h"
 #include "utf8.h"
 
-struct transliteration_letter *find_letter_by_code(unsigned long c,
-	struct transliteration_letter *table)
+const struct transliteration_letter *find_letter_by_code(unsigned long c,
+	const struct transliteration_letter *table)
 {
-	struct transliteration_letter *walk = table;
+	const struct transliteration_letter *walk = table;
+
+	if (c == 0)
+		return NULL;
+
+	while (walk->code != 0) {
+		if (c == walk->code)
+			return walk;
+		walk++;
+	}
+
+	return NULL;
+}
+
+const struct transliteration_modifier *find_modifier_by_code(unsigned long c,
+	const struct transliteration_modifier *table)
+{
+	const struct transliteration_modifier *walk = table;
+
+	if (c == 0)
+		return NULL;
 
 	while (walk->code != 0) {
 		if (c == walk->code)
@@ -28,7 +48,8 @@ char *transliterate_devanagari_to_latin(const char *text,
 	char *tmp;
 	unsigned long c;
 	struct syllable *head, *tail;
-	struct transliteration_letter *letter;
+	const struct transliteration_letter *letter;
+	const struct transliteration_modifier *modifier;
 
 	head = syllable_alloc("");
 	tail = head;
@@ -43,6 +64,12 @@ char *transliterate_devanagari_to_latin(const char *text,
 			continue;
 		}
 
+		modifier = find_modifier_by_code(c, context->table_modifiers);
+		if (modifier != NULL) {
+			modifier->modifier(tail);
+			continue;
+		}
+
 		tmp = utf8_code_to_string(c);
 		tail = syllable_append(tail, tmp);
 		free(tmp);

transliteration.h

@@ -1,13 +1,23 @@
 #ifndef __TRANSLITERATION_H
 #define __TRANSLITERATION_H
 
+#include "syllable.h"
+
 struct transliteration_letter {
 	unsigned long code;
 	const char *data;
 };
 
+typedef void (*syllable_modification_t)(struct syllable *syllable);
+
+struct transliteration_modifier {
+	unsigned long code;
+	syllable_modification_t modifier;
+};
+
 struct transliteration_context {
 	const struct transliteration_letter *table_letters;
+	const struct transliteration_modifier *table_modifiers;
 };
 
 char *transliterate_devanagari_to_latin(const char *text,