From 3b79b5751a6d10c6a0b8e784f5a3f4b09889fb01 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Fri, 10 Aug 2018 16:06:30 -0700
Subject: [PATCH] Add true and false keywords to the parser.

---
 include/lexer.h   |  2 ++
 include/tree.h    |  2 ++
 src/interpreter.c |  4 ++++
 src/lexer.c       |  8 +++++---
 src/parser.c      | 36 ++++++++++++++++++++++++++++++++++++
 5 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/include/lexer.h b/include/lexer.h
index 9a57655..764995f 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -60,6 +60,8 @@ enum libab_lexer_token_e {
     TOKEN_OP_PREFIX,
     TOKEN_OP_POSTFIX,
     TOKEN_OP_RESERVED,
+    TOKEN_KW_TRUE,
+    TOKEN_KW_FALSE,
     TOKEN_KW_IF,
     TOKEN_KW_ELSE,
     TOKEN_KW_WHILE,
diff --git a/include/tree.h b/include/tree.h
index d6b1870..223dc8b 100644
--- a/include/tree.h
+++ b/include/tree.h
@@ -19,6 +19,8 @@ enum libab_tree_variant_e {
     TREE_POSTFIX_OP,
     TREE_BLOCK,
     TREE_VOID,
+    TREE_TRUE,
+    TREE_FALSE,
     TREE_IF,
     TREE_WHILE,
     TREE_DOWHILE,
diff --git a/src/interpreter.c b/src/interpreter.c
index 499a0ee..08a0292 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -1208,6 +1208,10 @@ libab_result _interpreter_run(struct interpreter_state* state, libab_tree* tree,
                 vec_index(&tree->children, 0),
                 vec_index(&tree->children, 1),
                 into);
+    } else if(tree->variant == TREE_TRUE) {
+        libab_get_true_value(state->ab, into);
+    } else if(tree->variant == TREE_FALSE) {
+        libab_get_false_value(state->ab, into);
     } else {
         libab_get_unit_value(state->ab, into);
     }
diff --git a/src/lexer.c b/src/lexer.c
index 7ad154a..4f9a53f 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -10,6 +10,8 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
     const char* words[] = {".",
                            "[a-zA-Z][a-zA-Z0-9_]*",
                            "[0-9]+(\\.[0-9]*)?",
+                           "true",
+                           "false",
                            "if",
                            "else",
                            "while",
@@ -18,9 +20,9 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
                            "fun",
                            "return"};
     libab_lexer_token tokens[] = {
-        TOKEN_CHAR,    TOKEN_ID,        TOKEN_NUM,    TOKEN_KW_IF,
-        TOKEN_KW_ELSE, TOKEN_KW_WHILE,  TOKEN_KW_DO,  TOKEN_KW_ARROW,
-        TOKEN_KW_FUN,  TOKEN_KW_RETURN };
+        TOKEN_CHAR,     TOKEN_ID,       TOKEN_NUM,     TOKEN_KW_TRUE,
+        TOKEN_KW_FALSE, TOKEN_KW_IF,    TOKEN_KW_ELSE, TOKEN_KW_WHILE,
+        TOKEN_KW_DO,    TOKEN_KW_ARROW, TOKEN_KW_FUN,  TOKEN_KW_RETURN};
     const size_t count = sizeof(tokens) / sizeof(libab_lexer_token);
 
     eval_config_init(&lexer->config);
diff --git a/src/parser.c b/src/parser.c
index 28271c1..736aa32 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -406,6 +406,38 @@ libab_result _parse_void(struct parser_state* state, libab_tree** store_into) {
     return result;
 }
 
+libab_result _parse_true(struct parser_state* state, libab_tree** store_into) {
+    libab_result result = _parser_consume_type(state, TOKEN_KW_TRUE);
+    if(result == LIBAB_SUCCESS) {
+        if ((*store_into = malloc(sizeof(**store_into)))) {
+            (*store_into)->variant = TREE_TRUE;
+        } else {
+            result = LIBAB_MALLOC;
+        }
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        *store_into = NULL;
+    }
+    return result;
+}
+
+libab_result _parse_false(struct parser_state* state, libab_tree** store_into) {
+    libab_result result = _parser_consume_type(state, TOKEN_KW_FALSE);
+    if(result == LIBAB_SUCCESS) {
+        if ((*store_into = malloc(sizeof(**store_into)))) {
+            (*store_into)->variant = TREE_FALSE;
+        } else {
+            result = LIBAB_MALLOC;
+        }
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        *store_into = NULL;
+    }
+    return result;
+}
+
 libab_result _parse_if(struct parser_state* state, libab_tree** store_into) {
     libab_result result = LIBAB_SUCCESS;
     libab_tree* condition = NULL;
@@ -736,6 +768,10 @@ libab_result _parse_atom(struct parser_state* state, libab_tree** store_into) {
         result = _parse_fun(state, store_into);
     } else if (_parser_is_type(state, TOKEN_KW_RETURN)) {
         result = _parse_return(state, store_into);
+    } else if (_parser_is_type(state, TOKEN_KW_TRUE)) {
+        result = _parse_true(state, store_into);
+    } else if (_parser_is_type(state, TOKEN_KW_FALSE)) {
+        result = _parse_false(state, store_into);
     } else {
         result = LIBAB_UNEXPECTED;
     }