 M: variable link-effect? drop f ;
 M: variable print-stack-effect? drop f ;
 
+PREDICATE: typed-variable < variable
+    "variable-type" word-prop ;
+
+: [typed-getter] ( quot type -- quot )
+    1array '[ @ _ declare ] ;
+: [typed-setter] ( quot type -- quot )
+    instance-check-quot prepose ;
+
+: define-typed-variable ( word type -- )
+    dupd {
+        [ [ [variable-getter] ] dip [typed-getter] ]
+        [ [ [variable-setter] ] dip [typed-setter] ]
+        [ "variable-type" set-word-prop ]
+        [ initial-value swap set-global ]
+    } 2cleave (define-variable) ;
+
+SYNTAX: TYPED-VAR:
+    CREATE-WORD scan-object define-typed-variable ;    
+
+M: typed-variable definer drop \ TYPED-VAR: f ;
+M: typed-variable definition "variable-type" word-prop 1quotation ;
+
 TUPLE: global-box value ;
 
 PREDICATE: global-variable < variable
-    "variable-setter" word-prop def>> first global-box? ;
+    def>> first global-box? ;
 
 : [global-getter] ( box -- quot )
     '[ _ value>> ] ;

! (c)2010 Joe Groff bsd license
USING: accessors definitions fry kernel locals.types namespaces parser
see sequences words ;
FROM: help.markup.private => link-effect? ;
IN: variables



M: global-variable definer drop \ GLOBAL: f ;

INTERSECTION: typed-global-variable
    global-variable typed-variable ;

: define-typed-global ( word type -- )
    2dup "variable-type" set-word-prop
    dup initial-value global-box boa swap
    [ [ [global-getter] ] dip [typed-getter] ]
    [ [ [global-setter] ] dip [typed-setter] ] 2bi (define-variable) ;

SYNTAX: TYPED-GLOBAL:
    CREATE-WORD scan-object define-typed-global ;

M: typed-global-variable definer drop \ TYPED-GLOBAL: f ;

