From d72c79d0e25956fde9da4f4600fce36e6849f9f1 Mon Sep 17 00:00:00 2001
From: Vlasta Vesely <vlastavesely@protonmail.ch>
Date: Mon, 30 Apr 2018 18:14:39 +0200
Subject: [PATCH] introduce output filters

---
 iast-czech.c      | 11 +++++++++++
 iast.c            |  5 +++++
 transliteration.c | 13 +++++++++++++
 transliteration.h |  3 +++
 4 files changed, 32 insertions(+)

diff --git a/iast-czech.c b/iast-czech.c
index 0ce8568..fb73d9c 100644
--- a/iast-czech.c
+++ b/iast-czech.c
@@ -101,12 +101,23 @@ static const struct transliteration_letter table[] = {
 	{0, 0, NULL}
 };
 
+static void dummy_filter(struct syllable *chain)
+{
+	printf("%s%s\n", chain->next->data, chain->next->next->data);
+}
+
+static const transliteration_filter_t filters[] = {
+	dummy_filter,
+	NULL
+};
+
 struct transliteration_context *transliteration_context_iast_czech_alloc()
 {
 	struct transliteration_context *context;
 
 	context = malloc(sizeof(*context));
 	context->table = table;
+	context->filters = filters;
 
 	return context;
 }
diff --git a/iast.c b/iast.c
index 0cea1b5..f66ac59 100644
--- a/iast.c
+++ b/iast.c
@@ -99,12 +99,17 @@ static const struct transliteration_letter table[] = {
 	{0, 0, NULL}
 };
 
+static const transliteration_filter_t filters[] = {
+	NULL
+};
+
 struct transliteration_context *transliteration_context_iast_alloc()
 {
 	struct transliteration_context *context;
 
 	context = malloc(sizeof(*context));
 	context->table = table;
+	context->filters = filters;
 
 	return context;
 }
diff --git a/transliteration.c b/transliteration.c
index 711f84c..92c6952 100644
--- a/transliteration.c
+++ b/transliteration.c
@@ -36,6 +36,17 @@ static void syllable_modify(struct syllable *syllable, const char *data)
 	syllable->data = strdup(buffer);
 }
 
+static void apply_transliteration_filters(struct syllable *head,
+	const transliteration_filter_t *filters)
+{
+	const transliteration_filter_t *filter = filters;
+
+	while (*filter) {
+		(*filter)(head);
+		filter++;
+	}
+}
+
 char *transliterate_devanagari_to_latin(const char *text,
 	struct transliteration_context *context)
 {
@@ -72,6 +83,8 @@ char *transliterate_devanagari_to_latin(const char *text,
 		free(tmp);
 	}
 
+	apply_transliteration_filters(head, context->filters);
+
 	return syllable_chain_to_string(head);
 }
 
diff --git a/transliteration.h b/transliteration.h
index 22ca2f0..ed742d0 100644
--- a/transliteration.h
+++ b/transliteration.h
@@ -9,6 +9,8 @@
 #define FLAG_REGULAR	1 << 0
 #define FLAG_MODIFIER	1 << 1
 
+typedef void (*transliteration_filter_t)(struct syllable *syllable_chain);
+
 struct transliteration_letter {
 	unsigned int code;
 	unsigned int flags;
@@ -17,6 +19,7 @@ struct transliteration_letter {
 
 struct transliteration_context {
 	const struct transliteration_letter *table;
+	const transliteration_filter_t *filters;
 };
 
 char *transliterate_devanagari_to_latin(const char *text,