almost fibonacci but it needs the type checker

1 files changed, 33 insertions, 12 deletions

diff --git a/parser.c b/parser.c
index e078ae9..9a3e7f3 100644
--- a/parser.c
+++ b/parser.c
@@ -30,10 +30,9 @@ static void* protected_alloc(size_t sz) {
 
 static void unexpected_token(enum token_type expected) {
     /* TODO: print what token was expected */
-    PARSER_PANIC("unexpected token");
+    PARSER_PANIC("unexpected token; expected %d", expected);
 }
 
-/* TODO: reorganize the lexer to make peek cheaper */
 static void peek_or_panic() {
     if (!lexer_peek(&tok))
         PARSER_PANIC("unexpected EOF");
@@ -311,6 +310,25 @@ static void parse_group(struct group_node* p_node) {
     expect(TK_RCURLY);
 }
 
+static void parse_if(struct if_node* p_node) {
+    expect_kw("if");
+
+    expect(TK_LPAREN);
+    p_node->cond = protected_alloc(sizeof(struct expr_node));
+    parse_expr(p_node->cond);
+    expect(TK_RPAREN);
+
+    p_node->true_branch = protected_alloc(sizeof(struct stmt_node));
+    parse_stmt(p_node->true_branch);
+
+    peek_or_panic();
+    if (tok.type != TK_IDENT || strcmp(tok.data.ident, "else") != 0) return;
+    expect_kw("else");
+
+    p_node->false_branch = protected_alloc(sizeof(struct stmt_node));
+    parse_stmt(p_node->false_branch);
+}
+
 static void parse_stmt_assign(struct stmt_node* p_node) {
     peek_or_panic();
     if (tok.type != TK_ASSIGN) return;
@@ -346,7 +364,11 @@ static void parse_stmt(struct stmt_node* p_node) {
             parse_group(&p_node->inner.group);
             return;
         case TK_IDENT:
-            if (strcmp(tok.data.ident, "return") == 0) {
+            if (strcmp(tok.data.ident, "if") == 0) {
+                p_node->type = STMT_IF;
+                parse_if(&p_node->inner.if_);
+                return;
+            } else if (strcmp(tok.data.ident, "return") == 0) {
                 p_node->type = STMT_RETURN;
                 parse_return(&p_node->inner.return_);
                 break;
@@ -383,6 +405,14 @@ static void parse_fn_decl(struct fn_decl_node* p_node) {
     expect(TK_IDENT);
     p_node->name = tok.data.ident;
 
+    scope_define_var(scope, (struct var_def) {
+        .name = p_node->name,
+        .loc = {
+            .type = STO_FN,
+            .decl = p_node,
+        },
+    });
+
     expect(TK_LPAREN);
 
     scope_push(&scope);
@@ -393,15 +423,6 @@ static void parse_fn_decl(struct fn_decl_node* p_node) {
 
     expect(TK_RPAREN);
 
-    /* defining here makes recursion possible */
-    scope_define_var(scope, (struct var_def) {
-        .name = p_node->name,
-        .loc = {
-            .type = STO_FN,
-            .decl = p_node,
-        },
-    });
-
     parse_group(&p_node->body);
 
     scope_pop(&scope);