parser: Create the literal node type

Since we want to extend our code to support multiple kind of expression
it does not make sense that the return statement always return a number.

For now on, return statement has an ast_node_t as argument, meaning that
it could be anything. The literal_node_t was also implemented in order
to keep the application behavior.

Following the C's calling convention the literal values are stored at
%eax and the return takes this argument to do anything it is needed.

Signed-off-by: Carlos Maniero <carlosmaniero@gmail.com>
Reviewed-by: Johnny Richard <johnny@johnnyrichard.com>

1 files changed, 21 insertions, 4 deletions

diff --git a/src/ast.h b/src/ast.h
index fab90c1..1c4bbb8 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -29,7 +29,7 @@ typedef struct ast_visitor_t ast_visitor_t;
 typedef struct ast_node_t ast_node_t;
 
 typedef struct ast_return_stmt_t {
-  uint32_t number;
+  ast_node_t* argument;
 } ast_return_stmt_t;
 
 typedef struct ast_function_declaration_t {
@@ -38,19 +38,35 @@ typedef struct ast_function_declaration_t {
   ast_node_t* body;
 } ast_function_declaration_t;
 
+typedef enum {
+  AST_LITERAL_INTEGER
+} ast_literal_kind_t;
+
+typedef union {
+  uint32_t integer;
+} ast_literal_value_t;
+
+typedef struct ast_literal_t {
+  ast_literal_kind_t kind;
+  ast_literal_value_t value;
+} ast_literal_t;
+
 typedef struct ast_visitor_t {
   void (*visit_function)(struct ast_visitor_t *, ast_function_declaration_t *);
   void (*visit_return_stmt)(struct ast_visitor_t *, ast_return_stmt_t *);
+  void (*visit_literal)(struct ast_visitor_t *, ast_literal_t *);
 } ast_visitor_t;
 
 typedef enum {
-  AST_UNKOWN_NODE,
   AST_FUNCTION_DECLARATION,
-  AST_RETURN_STMT
+  AST_LITERAL,
+  AST_RETURN_STMT,
+  AST_UNKOWN_NODE
 } ast_node_kind_t;
 
 typedef union {
   ast_function_declaration_t function;
+  ast_literal_t literal;
   ast_return_stmt_t return_stmt;
 } ast_node_data_t;
 
@@ -66,7 +82,8 @@ ast_node_t* ast_node_new();
 void ast_node_destroy(ast_node_t *node);
 
 void ast_node_init_function_declaration(ast_node_t* node, string_view_t name, type_t return_type, ast_node_t *body);
-void ast_node_init_return_stmt(ast_node_t* node, uint32_t number);
+void ast_node_init_return_stmt(ast_node_t* node, ast_node_t *argument);
+void ast_literal_integer_create(ast_node_t* node, uint32_t number);
 
 #endif /* AST_H */