From d3813dc514bf2506ba3e758e7436a86e280c18a9 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Fri, 6 Dec 2024 13:22:33 +0000
Subject: [PATCH] lang: ast: treat bang (!) as an unconsumed expression
 terminator

---
 lang/ast/expr/arith.c | 21 +++++++++++++++++++++
 lang/ast/expr/expr.c  |  1 +
 lang/ast/expr/expr.h  |  2 ++
 3 files changed, 24 insertions(+)

diff --git a/lang/ast/expr/arith.c b/lang/ast/expr/arith.c
index 5a4c0d2..91fe4a8 100644
--- a/lang/ast/expr/arith.c
+++ b/lang/ast/expr/arith.c
@@ -985,6 +985,27 @@ struct token_parse_result arith_parse_dot(
 	return expr_finalise_and_return(ctx, state);
 }
 
+struct token_parse_result arith_parse_bang(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct expr_parser_state *state
+		= parser_get_state(ctx, struct expr_parser_state);
+
+	if (state->s_type != EXPR_TYPE_ARITH) {
+		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	}
+
+	if (state->s_paren_depth > 0) {
+		/* end-of-expression with mismatched parentheses */
+		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
+	}
+
+	state->s_prev_token = IVY_SYM_BANG;
+	struct token_parse_result result = expr_finalise_and_return(ctx, state);
+	result.r_flags = PARSE_REPEAT_TOKEN;
+	return result;
+}
+
 struct token_parse_result arith_parse_caret(
 	struct ivy_parser *ctx, struct ivy_token *tok)
 {
diff --git a/lang/ast/expr/expr.c b/lang/ast/expr/expr.c
index 68a4af6..bce7c6d 100644
--- a/lang/ast/expr/expr.c
+++ b/lang/ast/expr/expr.c
@@ -36,6 +36,7 @@ struct ast_node_type expr_node_ops = {
 		SYM_PARSER(CARET, arith_parse_caret),
 		SYM_PARSER(COMMA, arith_parse_comma),
 		SYM_PARSER(DOT, arith_parse_dot),
+		SYM_PARSER(BANG, arith_parse_bang),
 		SYM_PARSER(EQUAL_RIGHT_ANGLE, arith_parse_equal_right_angle),
 	},
 	.n_keyword_parsers = {
diff --git a/lang/ast/expr/expr.h b/lang/ast/expr/expr.h
index d62c60a..6359ba7 100644
--- a/lang/ast/expr/expr.h
+++ b/lang/ast/expr/expr.h
@@ -120,6 +120,8 @@ extern struct token_parse_result arith_parse_semicolon(
 	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_dot(
 	struct ivy_parser *ctx, struct ivy_token *tok);
+extern struct token_parse_result arith_parse_bang(
+	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_caret(
 	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_comma(