From 2db840288d43ed44481306b203bb7d27325a3a56 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sat, 10 Feb 2018 14:21:04 -0800
Subject: [PATCH] Implement the initialization and freeing of lexer.

---
 include/lexer.h | 27 ++++++++++++++++++++++++++
 src/lexer.c     | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/include/lexer.h b/include/lexer.h
index f816ce7..702ba5e 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -17,7 +17,34 @@ struct lexer {
     eval_config config;
 };
 
+/**
+ * The various tokens used by the lexer
+ * in order to tag meaningful sequences
+ * of characters.
+ */
+enum lexer_token {
+    TOKEN_CHAR = 0,
+    TOKEN_ID,
+    TOKEN_TRUE,
+    TOKEN_FALSE,
+    TOKEN_NUM,
+    TOKEN_STR,
+    TOKEN_CHAR_LIT,
+    TOKEN_KW_FUN,
+    TOKEN_KW_IF,
+    TOKEN_KW_ELSE,
+    TOKEN_KW_WHILE,
+    TOKEN_KW_DO,
+    TOKEN_KW_FOR,
+    TOKEN_KW_RETURN,
+    TOKEN_OP_INFIX,
+    TOKEN_OP_POSTFIX,
+    TOKEN_OP_PREFIX,
+    TOKEN_LAST
+};
+
 typedef struct lexer lexer;
+typedef enum lexer_token lexer_token;
 
 /**
  * Initializes the given lexer,
diff --git a/src/lexer.c b/src/lexer.c
index 723ab1d..26765f2 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -1 +1,52 @@
 #include "lexer.h"
+
+libab_result lexer_init(lexer* lexer) {
+    size_t i;
+    libab_result result = LIBAB_SUCCESS;
+    const char* words[] = {
+        ".",
+        "[a-zA-Z][a-zA-Z0-9_]*",
+        "true",
+        "false",
+        "[0-9]+(\\.[0-9]*)",
+        "\"[^\"]*\"",
+        "'[^']'",
+        "fun",
+        "if",
+        "else",
+        "while",
+        "do",
+        "for",
+        "return"
+    };
+    lexer_token tokens[] = {
+        TOKEN_CHAR,
+        TOKEN_ID,
+        TOKEN_TRUE,
+        TOKEN_FALSE,
+        TOKEN_NUM,
+        TOKEN_STR,
+        TOKEN_CHAR_LIT,
+        TOKEN_KW_FUN,
+        TOKEN_KW_IF,
+        TOKEN_KW_ELSE,
+        TOKEN_KW_WHILE,
+        TOKEN_KW_DO,
+        TOKEN_KW_FOR,
+        TOKEN_KW_RETURN
+    };
+    const size_t count = sizeof(tokens)/sizeof(lexer_token);
+
+    eval_config_init(&lexer->config);
+    for(i = 0; i < count && result == LIBAB_SUCCESS; i++) {
+        result =
+            (eval_config_add(&lexer->config, words[i], tokens[i]) == LIBLEX_SUCCESS)
+            ? LIBAB_SUCCESS : LIBAB_MALLOC;
+    }
+
+    return result;
+}
+libab_result lexer_free(lexer* lexer) {
+    return (eval_config_free(&lexer->config) == LIBLEX_SUCCESS) ?
+        LIBAB_SUCCESS : LIBAB_MALLOC;
+}