parser: create a block node type

Since the next step to pipa programming language is about having control
flow statements we could benefit ourselves by having a block node to
control scope. Now, functions has a block node, instead of an vector as
body. As you can see through the ast-dump:

  FunctionDecl name='main'
  └─ body:
    └─ Block
      └─ ReturnStmt
        └─ Literal type=i32 value='69'

This same node kind can be used for parsing if, for and while blocks.

I could use ast_block_t as body for functions but instead, I opted to
use an ast_node_t. This brings the flexibility to, in the future, having
another function body kinds, such as arrow functions if we want to:

  fn add(a: i32, b: i32): i32 => a + b;

Signed-off-by: Carlos Maniero <carlos@maniero.me>

1 files changed, 8 insertions, 7 deletions

diff --git a/src/parser.c b/src/parser.c
index 2817fa0..848bb4a 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -516,9 +516,11 @@ parser_error_report_unexpected_token(parser_t *parser)
 }
 
 static bool
-parser_ensure_function_return_statement(parser_t *parser, vector_t *body, token_t *function_token)
+parser_ensure_function_return_statement(parser_t *parser, ast_node_t *block, token_t *function_token)
 {
-  ast_node_t *latest_node = vector_at(body, body->size - 1);
+  assert(block->kind == AST_BLOCK);
+
+  ast_node_t *latest_node = vector_at(block->data.block.body, block->data.block.body->size - 1);
 
   if (latest_node->kind != AST_RETURN_STMT) {
     parser_error_t error;
@@ -527,14 +529,13 @@ parser_ensure_function_return_statement(parser_t *parser, vector_t *body, token_
     sprintf(error.message, "expected 'return' keyword.");
 
     parser->errors[parser->errors_len++] = error;
-    vector_destroy(body);
     return false;
   }
 
   return true;
 }
 
-static vector_t *
+static ast_node_t *
 parser_parse_block_declarations(parser_t *parser, type_t result_type)
 {
   if (!drop_expected_token(parser, TOKEN_OCURLY)) {
@@ -602,7 +603,7 @@ parser_parse_block_declarations(parser_t *parser, type_t result_type)
     return NULL;
   }
 
-  return body;
+  return ast_node_new_block(body);
 }
 
 static bool
@@ -638,14 +639,14 @@ parser_parse_function_declaration(parser_t *parser)
     return NULL;
   }
 
-  vector_t *body = parser_parse_block_declarations(parser, return_type);
+  ast_node_t *body = parser_parse_block_declarations(parser, return_type);
 
   if (body == NULL) {
     return NULL;
   }
 
   if (!parser_ensure_function_return_statement(parser, body, &func_name_token)) {
-    vector_destroy(body);
+    ast_node_destroy(body);
     return NULL;
   }