From 22063462a90b5c290f5f71319b259fca80da8097 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Thu, 4 Jul 2024 13:37:23 -0400
Subject: Add __length and __negative metamethods

---
 typecheck.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

(limited to 'typecheck.c')

diff --git a/typecheck.c b/typecheck.c
index 6a4dbaca..d21d28ad 100644
--- a/typecheck.c
+++ b/typecheck.c
@@ -741,10 +741,19 @@ type_t *get_type(env_t *env, ast_t *ast)
     case Pass: return Type(VoidType);
     case Length: return Type(IntType, .bits=64);
     case Negative: {
-        type_t *t = get_type(env, Match(ast, Negative)->value);
+        ast_t *value = Match(ast, Negative)->value;
+        type_t *t = get_type(env, value);
         if (t->tag == IntType || t->tag == NumType)
             return t;
-        code_err(ast, "I only know how to get negatives of numeric types, not %T", t);
+
+        binding_t *b = get_namespace_binding(env, value, "__negative");
+        if (b && b->type->tag == FunctionType) {
+            auto fn = Match(b->type, FunctionType);
+            if (fn->args && can_promote(t, get_arg_type(env, fn->args)))
+                return fn->ret;
+        }
+
+        code_err(ast, "I don't know how to get the negative value of type %T", t);
     }
     case Not: {
         type_t *t = get_type(env, Match(ast, Not)->value);
-- 
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