X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=644ee1914c221ab38227825a97f09599391140a6;hb=22e181f918b5518f64ee693c492469d11f2898ac;hp=1953cf98cf0ec004d9bbbe7c4a54acc96b93d4f6;hpb=dc6e0cea1e1e982da8029c94d78ee66ab7e8fd82;p=scheme.forth.jl.git

diff --git a/scheme.4th b/scheme.4th
index 1953cf9..644ee19 100644
--- a/scheme.4th
+++ b/scheme.4th
@@ -296,6 +296,17 @@ global-env setobj
     then
 ;
 
+: arg-type-error
+            bold fg red ." Incorrect argument type." reset-term cr
+            abort
+;
+
+: ensure-arg-type ( arg type -- )
+    istype? false = if
+        arg-type-error
+    then
+;
+
 include scheme-primitives.4th
 
 \ }}}