implemented variable parsing

lc.c

@@ -138,7 +138,8 @@ void print_ast(ast_node *node, int depth) {
 			printf("IfStmt (Fields missing in struct)\n");
 			break;
 		case NODE_VAR_DECL:
-			printf("VarDecl (Fields missing in struct)\n");
+			printf("VarDecl: %.*s: %.*s\n", (int)node->expr.var_decl.name_len, node->expr.var_decl.name, (int)node->expr.var_decl.type_len, node->expr.var_decl.type);
+			print_ast(node->expr.var_decl.value, depth + 1);
 			break;
 		case NODE_FUNCTION:
 			printf("FunctionDef (Fields missing in struct)\n");

parser.c

@@ -448,7 +448,7 @@ ast_node *parse_expression(parser *p)
 		return node;
 	}
 
-	if ((p->tokens->type >= TOKEN_DOUBLE_EQ && p->tokens->type <= TOKEN_NOT_EQ) || (p->tokens->type >= TOKEN_LSHIFT_EQ && p->tokens->type <= TOKEN_DOUBLE_AND))
+	if (p->tokens && ((p->tokens->type >= TOKEN_DOUBLE_EQ && p->tokens->type <= TOKEN_NOT_EQ) || (p->tokens->type >= TOKEN_LSHIFT_EQ && p->tokens->type <= TOKEN_DOUBLE_AND)))
 	{
 		binary_op op;
 		switch (p->tokens->type)
@@ -777,6 +777,31 @@ static ast_node *parse_statement(parser *p)
 			return parse_while(p);
 		}
 	}
+	else if (match_peek(p, TOKEN_IDENTIFIER) && p->tokens->next && p->tokens->next->type == TOKEN_IDENTIFIER)
+	{
+		/* Variable declaration. */
+		ast_node *node = arena_alloc(p->allocator, sizeof(ast_node));
+		node->type = NODE_VAR_DECL;
+		node->expr.var_decl.type = p->tokens->lexeme;
+		node->expr.var_decl.type_len = p->tokens->lexeme_len;
+		advance(p);
+		node->expr.var_decl.name = p->tokens->lexeme;
+		node->expr.var_decl.name_len = p->tokens->lexeme_len;
+		advance(p);
+		if (match(p, TOKEN_EQ)) {
+			node->expr.var_decl.value = parse_expression(p);
+		} else {
+			node->expr.var_decl.value = NULL;
+		}
+
+		if (!match(p, TOKEN_SEMICOLON))
+		{
+			error(p, "expected `;` after statement.");
+			return NULL;
+		}
+
+		return node;
+	}
 	else
 	{
 		ast_node *expr = parse_expression(p);

parser.h

@@ -170,6 +170,13 @@ typedef struct _ast_node {
 			struct _ast_node **statements;
 			usize stmt_len;
 		} compound;
+		struct {
+			struct _ast_node *value;
+			char *name;
+			usize name_len;
+			char *type;
+			usize type_len;
+		} var_decl;
 	} expr;
 } ast_node;
 

test.c

@@ -1,3 +1 @@
-loop i != 0 {
-	printf("%d\n", i);
-}
+u32 a = 3;