From 0ff71a9389d0cbdde610b38758f0cd158df34408 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 10 Feb 2018 17:09:35 -0800
Subject: [PATCH] Implement lexing code.

---
 include/lexer.h | 44 +++++++++++++++++++++++++++++++
 src/lexer.c     | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/include/lexer.h b/include/lexer.h
index 702ba5e..529375c 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -17,6 +17,35 @@ struct lexer {
     eval_config config;
 };
 
+/**
+ * A token that is produced by the lexer.
+ */
+struct lexer_match {
+    /**
+     * The line that this token was found on.
+     */
+    size_t line;
+    /**
+     * The first index at which this token's string
+     * begins.
+     */
+    size_t from;
+    /**
+     * The index of the first character that is outside
+     * this token.
+     */
+    size_t to;
+    /**
+     * The index of the beginning of the line on which
+     * this token is found.
+     */
+    size_t line_from;
+    /**
+     * The type of token.
+     */
+    int type;
+};
+
 /**
  * The various tokens used by the lexer
  * in order to tag meaningful sequences
@@ -45,6 +74,7 @@ enum lexer_token {
 
 typedef struct lexer lexer;
 typedef enum lexer_token lexer_token;
+typedef struct lexer_match lexer_match;
 
 /**
  * Initializes the given lexer,
@@ -53,6 +83,14 @@ typedef enum lexer_token lexer_token;
  * @return the result of the operation (can be MALLOC on failed allocation.)
  */
 libab_result lexer_init(lexer* lexer);
+/**
+ * Turns the given input string into tokens.
+ * @param lexer the lexer to use to turn the string into tokens.
+ * @param string the string to turn into tokens.
+ * @param lex_into the list which should be populated with matches.
+ * @return the result of the operation.
+ */
+libab_result lexer_lex(lexer* lexer, const char* string, ll* lext_into);
 /**
  * Releases the memory associated with the given lexer,
  * removing all registered patterns from it.
@@ -60,5 +98,11 @@ libab_result lexer_init(lexer* lexer);
  * @return the result of the operation.
  */
 libab_result lexer_free(lexer* lexer);
+/**
+ * Function intended to be passed to "foreach" calls
+ * in libds. lexer_lex allocates matches, and passing this function
+ * to foreach will free the memory allocated for the matches.
+ */
+int lexer_foreach_match_free(void* data, va_list args);
 
 #endif
diff --git a/src/lexer.c b/src/lexer.c
index 494487e..7129fec 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -1,5 +1,8 @@
 #include "lexer.h"
+#include "ll.h"
 #include "libabacus_util.h"
+#include <stdlib.h>
+#include <ctype.h>
 
 libab_result lexer_init(lexer* lexer) {
     size_t i;
@@ -46,6 +49,72 @@ libab_result lexer_init(lexer* lexer) {
 
     return result;
 }
+
+struct lexer_state {
+    size_t line;
+    size_t line_from;
+    const char* source;
+    ll* matches;
+};
+int _lexer_foreach_convert_match(void* data, va_list args) {
+    libab_result result = LIBAB_SUCCESS;
+    lexer_match* new_match;
+    match* match = data;
+    struct lexer_state* state = va_arg(args, struct lexer_state*);
+    char first_char = state->source[match->from];
+    if(isspace(first_char)) {
+        // Skip
+    } else if(first_char == '\n') { 
+        state->line++;
+        state->line_from = match->to;
+    } if((new_match = malloc(sizeof(*new_match)))) {
+        new_match->from = match->from;
+        new_match->to = match->to;
+        new_match->line_from = state->line_from;
+        new_match->line = state->line;
+        result = convert_ds_result(ll_append(state->matches, new_match));
+        if(result != LIBAB_SUCCESS) {
+            free(new_match);
+        }
+    } else {
+        result = LIBAB_MALLOC;
+    }
+    return result;
+}
+
+libab_result lexer_lex(lexer* lexer, const char* string, ll* lex_into) {
+    libab_result result;
+    ll raw_matches;
+    struct lexer_state state;
+
+    ll_init(&raw_matches);
+
+    state.line = 0;
+    state.line_from = 0;
+    state.matches = lex_into;
+    state.source = string;
+
+    result = convert_lex_result(
+            eval_all(string, 0, &lexer->config, &raw_matches));
+
+    if(result == LIBAB_SUCCESS) {
+        result = ll_foreach(&raw_matches, NULL, compare_always,
+                _lexer_foreach_convert_match, &state);
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        ll_foreach(lex_into, NULL, compare_always, lexer_foreach_match_free);
+    }
+
+    ll_foreach(&raw_matches, NULL, compare_always, eval_foreach_match_free);
+    ll_free(&raw_matches);
+
+    return result;
+}
 libab_result lexer_free(lexer* lexer) {
     return convert_lex_result(eval_config_free(&lexer->config));
 }
+int lexer_foreach_match_free(void* data, va_list args) {
+    free((lexer_match*) data);
+    return 0;
+}