fix whenLet (for all targets, I think). close #64

kiss/src/kiss/Macros.hx

@@ -689,22 +689,25 @@ class Macros {
                 b.symbol("null");
             };
 
-            return b.callSymbol("case", [
-                firstValue,
-                b.call(
-                    firstPattern, [
-                        if (bindingList.length == 0) {
-                            thenExp;
-                        } else {
-                            ifLet(assertLet, wholeExp, [
-                                b.list(bindingList)
-                            ].concat(exps.slice(1)), k);
-                        }
-                    ]),
-                b.callSymbol("otherwise", [
+            var gensym = b.symbol();
+            return b.let(
+                [gensym, firstValue],
+                [b.callSymbol("case", [
+                    gensym,
+                    b.call(
+                        b.callSymbol("when", [gensym, firstPattern]), [
+                            if (bindingList.length == 0) {
+                                thenExp;
+                            } else {
+                                ifLet(assertLet, wholeExp, [
+                                    b.list(bindingList)
+                                ].concat(exps.slice(1)), k);
+                            }
+                        ]),
+                    b.callSymbol("otherwise", [
                         elseExp
-                ])
-            ]);
+                    ])
+                ])]);
         }
         macros["ifLet"] = ifLet.bind(false);
 
@@ -1177,10 +1180,8 @@ class Macros {
                 b.callField(funcName, exps.shift(), exps),
                 b.callSymbol("-1", [b.symbol("haxe.ds.Option.None")]),
                 b.callSymbol("other", [b.callSymbol("haxe.ds.Option.Some", [b.symbol("other")])]),
+                b.callSymbol("null", [b.callSymbol("throw", [b.str("Haxe indexOf is broken")])])
             ];
-            if (!(Context.defined('cs') || Context.defined('cpp'))) {
-                cases.push(b.callSymbol("null", [b.callSymbol("throw", [b.str("Haxe indexOf is broken")])]));
-            }
             return b.callSymbol("case", cases);
         }
         macros["indexOf"] = indexOfMacro.bind(false);

kiss/src/kiss/Prelude.hx

@@ -349,6 +349,13 @@ class Prelude {
 
     public static var joinPath:Function = Reflect.makeVarArgs(_joinPath);
 
+    public static function isNull(v:Any) {
+        return switch (Type.typeof(v)) {
+            case TNull: true;
+            default: false;
+        }
+    }
+
     public static dynamic function truthy<T>(v:T) {
         return switch (Type.typeof(v)) {
             case TNull: false;

kiss/src/kiss/SpecialForms.hx

@@ -338,22 +338,7 @@ class SpecialForms {
 
             var exp = k.withoutListWrapping().convert(args[0]);
 
-            // On C#, C++, and HashLink, value types (specifically Float and Int) cannot be null, so they cannot be compared with null.
-            // Therefore a null case doesn't need to be added--and will cause a compile failure if it is.
-            var canCompareNull = !isTupleCase &&
-                    if (Context.defined('cs') || Context.defined('cpp') || Context.defined('hl')) {
-                        var type = exp.typeof(k.typeHints);
-                        switch (type) {
-                            case null:
-                                false;
-                            case Success(TAbstract(ref, [])) if (["Int", "Float", "Bool"].indexOf(ref.get().name) != -1):
-                                false;
-                            case Failure(_):
-                                KissError.warnFromExp(args[0], "Can't detect whether expression can be null-checked");
-                                false;
-                            default: true;
-                        }
-                    } else true;
+            var canCompareNull = !isTupleCase;
 
             var cases = args.slice(1);
             // case also override's haxe's switch() behavior by refusing to match null values against <var> patterns.
@@ -375,8 +360,11 @@ class SpecialForms {
                     throw KissError.fromExp(wholeExp, "Unmatched pattern: null");
                 }
 
-                var nullCase = b.callSymbol("null", [b.raw(nullExpr.toString())]);
-                
+                var nullCase = if (k.hscript) {
+                    b.callSymbol("null", [b.raw(nullExpr.toString())]);  
+                } else {
+                    b.call(b.callSymbol("when", [b.callSymbol("Prelude.isNull", [b.symbol("v")]), b.symbol("v")]), [b.raw(nullExpr.toString())]);
+                };
 
                 cases.insert(0, nullCase);
             }