parser: Create parser for function with return statements

This is a very limited parser implementation which parses a single
function with return type i32 and body containing a return number statement.

The parser doesn't show the 'filepath:row:col' when it fails, a future
improvement would be display it to easy find where the compilation
problem is located.

The ast_nodes are taking the token.value ownership (which is a really
bad design since not all token.value ownership has been taken causing
memory leaking) but we never free them.  For a future fix we could use a
string_view instead since we never change the original source code. The
string_view will also improve the performance a lot avoiding unnecessary
heap memory allocation.

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/src/parser.h b/src/parser.h
new file mode 100644
index 0000000..e9a1cb7
--- /dev/null
+++ b/src/parser.h
@@ -0,0 +1,45 @@
+/*
+* Copyright (C) 2023 Johnny Richard
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#ifndef PARSER_H
+#define PARSER_H
+
+#include "lexer.h"
+
+typedef struct parser_t {
+  lexer_t *lexer;
+} parser_t;
+
+typedef enum {
+  TYPE_I32
+} type_t;
+
+typedef struct ast_return_stmt_t {
+  uint32_t number;
+} ast_return_stmt_t;
+
+typedef struct ast_function_t {
+  char   *name;
+  type_t  return_type;
+  ast_return_stmt_t body;
+} ast_function_t;
+
+void parser_init(parser_t *parser, lexer_t *lexer);
+
+ast_function_t parser_parse_function(parser_t *parser);
+
+#endif /* PARSER_H */
+