From 976b6d1b1a078bc3232a73ff8eead13a8a213484 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Tue, 27 Feb 2018 11:57:45 -0800
Subject: [PATCH] Add code to parse while loops.

---
 include/lexer.h |  1 +
 include/tree.h  |  1 +
 src/debug.c     |  1 +
 src/lexer.c     |  4 +++-
 src/parser.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 src/tree.c      |  2 +-
 6 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/include/lexer.h b/include/lexer.h
index 0ebc1b1..2c3437f 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -60,6 +60,7 @@ enum libab_lexer_token_e {
     TOKEN_OP_POSTFIX,
     TOKEN_KW_IF,
     TOKEN_KW_ELSE,
+    TOKEN_KW_WHILE,
     TOKEN_LAST
 };
 
diff --git a/include/tree.h b/include/tree.h
index fd30fc4..addd379 100644
--- a/include/tree.h
+++ b/include/tree.h
@@ -17,6 +17,7 @@ enum libab_tree_variant_e {
     BLOCK,
     VOID,
     IF,
+    WHILE,
     CALL
 };
 
diff --git a/src/debug.c b/src/debug.c
index c3038b2..8532db4 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -13,6 +13,7 @@ const char* _debug_node_name(libab_tree_variant var) {
         "block",
         "void",
         "if",
+        "while",
         "call"
     };
     return names[var];
diff --git a/src/lexer.c b/src/lexer.c
index 5b6596b..7f65373 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -12,7 +12,8 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
         "[a-zA-Z][a-zA-Z0-9_]*",
         "[0-9]+(\\.[0-9]*)?",
         "if",
-        "else"
+        "else",
+        "while",
     };
     libab_lexer_token tokens[] = {
         TOKEN_CHAR,
@@ -20,6 +21,7 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
         TOKEN_NUM,
         TOKEN_KW_IF,
         TOKEN_KW_ELSE,
+        TOKEN_KW_WHILE,
     };
     const size_t count = sizeof(tokens)/sizeof(libab_lexer_token);
 
diff --git a/src/parser.c b/src/parser.c
index 2dbfb2a..a1a1ccf 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -227,6 +227,45 @@ libab_result _parse_if(struct parser_state* state, libab_tree** store_into) {
     return result;
 }
 
+libab_result _parse_while(struct parser_state* state, libab_tree** store_into) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_tree* condition = NULL;
+    libab_tree* value = NULL;
+
+    if(_parser_is_type(state, TOKEN_KW_WHILE)) {
+        result = _parser_construct_node_vec(state->current_match, store_into);
+        if(result == LIBAB_SUCCESS) {
+            (*store_into)->variant = WHILE;
+            _parser_state_step(state);
+        }
+    } else {
+        result = LIBAB_UNEXPECTED;
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        result = _parser_consume_char(state, '(');
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        PARSE_CHILD(result, state, _parse_expression, condition, &(*store_into)->children);
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        result = _parser_consume_char(state, ')');
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        PARSE_CHILD(result, state, _parse_expression, value, &(*store_into)->children);
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        if(*store_into) libab_tree_free_recursive(*store_into);
+        *store_into = NULL;
+    }
+    
+    return result;
+}
+
 libab_result _parse_call(struct parser_state* state, libab_tree** store_into) {
     libab_result result =  LIBAB_SUCCESS;
     libab_tree* temp;
@@ -285,6 +324,8 @@ libab_result _parse_atom(struct parser_state* state, libab_tree** store_into) {
         _parser_state_step(state);
     } else if(_parser_is_type(state, TOKEN_KW_IF)) {
         result = _parse_if(state, store_into);
+    } else if(_parser_is_type(state, TOKEN_KW_WHILE)) {
+        result = _parse_while(state, store_into);
     } else if(_parser_is_char(state, '{')) {
         result = _parse_block(state, store_into, 1);
     } else {
diff --git a/src/tree.c b/src/tree.c
index 99c447e..e4bdbd1 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -4,7 +4,7 @@
 int libab_tree_has_vector(libab_tree_variant variant) {
     return variant == BASE || variant == OP ||
             variant == UNARY_OP || variant == BLOCK ||
-            variant == IF || variant == CALL;
+            variant == IF || variant == CALL || variant == WHILE;
 }
 
 int libab_tree_has_string(libab_tree_variant variant) {