From 750c26fedb02db025bcb86176a7d94cb386b6b18 Mon Sep 17 00:00:00 2001
From: Quinn Stephens <quinn@osmora.org>
Date: Mon, 9 Jun 2025 21:09:21 -0400
Subject: parser: Work on parsing function declarations

Signed-off-by: Quinn Stephens <quinn@osmora.org>
---
 src/parser/parser.c | 74 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 64 insertions(+), 10 deletions(-)

(limited to 'src/parser/parser.c')

diff --git a/src/parser/parser.c b/src/parser/parser.c
index 039bfa6..6f795cc 100644
--- a/src/parser/parser.c
+++ b/src/parser/parser.c
@@ -32,6 +32,7 @@
 #include "lexer.h"
 #include "log.h"
 #include "parser.h"
+#include "parser/ast.h"
 #include "parser/types.h"
 
 static void
@@ -46,33 +47,86 @@ tok_error(struct token *tok, const char *fmt, ...)
 }
 
 static bool
-parse_declaration(struct lexer *lexer, struct token *tok)
+parse_func_decl(struct lexer *lexer, struct token *tok, struct ast_node *func)
 {
-    struct type *typ;
+    /*
+     * TODO: Parse parameters.
+     */
+    lexer_next(lexer, tok);
+    if (tok->kind != TOK_RPAREN) {
+        tok_error(tok, "expected \")\" after \"(\"\n");
+        free(func);
+        return false;
+    }
 
     /*
-     * TODO: Support custom types.
+     * TODO: Parse body.
+     */
+    lexer_next(lexer, tok);
+    if (tok->kind != TOK_SEMICOLON) {
+        tok_error(tok, "expected \";\" after \")\"\n");
+        free(func);
+        return false;
+    }
+
+    /*
+     * TODO: Keep track of nodes.
+     */
+    log_debug("Parsed function \"%.*s\" (return type %s)\n", func->name_len, func->name, func->type->name);
+    free(func);
+
+    lexer_next(lexer, tok);
+    return true;
+}
+
+static bool
+parse_decl(struct lexer *lexer, struct token *tok)
+{
+    struct type *type;
+    struct ast_node *node;
+
+    /*
+     * TODO: Parse custom types.
      */
     if (!(tok->flags & TF_BUILTIN_TYPE)) {
-        tok_error(tok, "expected built-in type\n");
+        tok_error(tok, "expected type\n");
         return false;
     }
 
-    typ = types_find_builtin(tok->kind);
-    if (typ == NULL) {
+    type = types_find_builtin(tok->kind);
+    if (type == NULL) {
         return false;
     }
 
     lexer_next(lexer, tok);
     if (tok->kind != TOK_IDENTIFIER) {
-        tok_error(tok, "expected identifier\n");
+        tok_error(tok, "expected identifier after type\n");
+        return false;
+    }
+
+    node = malloc(sizeof(struct ast_node));
+    if (node == NULL) {
+        log_error("failed to allocate memory for AST node\n");
         return false;
     }
 
-    log_debug("name: \"%.*s\", type: { name: \"%s\", size: %lu }\n", tok->len, tok->pos, typ->name, typ->size);
+    node->kind = NOK_UNKNOWN;
+    node->name = tok->pos;
+    node->name_len = tok->len;
+    node->type = type;
+    node->ptr_levels = 0;
 
     lexer_next(lexer, tok);
-    return true;
+    if (tok->kind == TOK_LPAREN) {
+        return parse_func_decl(lexer, tok, node);
+    }
+
+    /*
+     * TODO: Parse variable declarations.
+     */
+    tok_error(tok, "expected \"(\" after identifier\n");
+    free(node);
+    return false;
 }
 
 bool
@@ -95,7 +149,7 @@ parser_parse(struct lexer *lexer)
         }
 
         if ((tok.flags & TF_BUILTIN_TYPE) || tok.kind == TOK_IDENTIFIER) {
-            success = parse_declaration(lexer, &tok);
+            success = parse_decl(lexer, &tok);
         }
 
         if (!success) {
-- 
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