added as keyword for case. close #29

kiss/src/kiss/Kiss.hx

@@ -284,6 +284,7 @@ class Kiss {
         var copy = withoutListWrapping(k);
         copy.macros.remove("or");
         copy.specialForms["or"] = SpecialForms.caseOr;
+        copy.specialForms["as"] = SpecialForms.caseAs;
         return copy;
     }
 

kiss/src/kiss/SpecialForms.hx

@@ -371,4 +371,9 @@ class SpecialForms {
             macro ${k.convert(args[0])} | ${caseOr(wholeExp, args.slice(1), k)};
         };
     };
+
+    public static function caseAs(wholeExp:ReaderExp, args:Array<ReaderExp>, k:KissState):Expr {
+        wholeExp.checkNumArgs(2, 2, "(as [name] [pattern])");
+        return macro ${k.convert(args[0])} = ${k.convert(args[1])};
+    };
 }

kiss/src/test/cases/BasicTestCase.kiss

@@ -360,6 +360,13 @@
     (case (Some 5)
         ((Some (or 6 5 4))
             (Assert.pass))
+        (otherwise (Assert.fail)))
+    // In Haxe, name = Pattern can be used in switch/case to match values: https://haxe.org/manual/lf-pattern-matching-variable-capture.html
+    // In Kiss, the syntax for this is (as name pattern)
+    (case (Some (Some 5))
+        ((Some (as inner (Some v)))
+            (Assert.equals 5 v)
+            (Assert.isTrue (Type.enumEq (Some 5) inner)))
         (otherwise (Assert.fail))))
 
 (defun _testMaps []