(when...)

src/kiss/Macros.hx

@@ -52,7 +52,12 @@ class Macros {
 
         macros["_eq"] = foldMacro("Prelude.areEqual");
 
-        // TODO when
+        macros["when"] = (args:Array<ReaderExp>, k) -> {
+            CallExp(Symbol("if").withPos(args[0].pos), [
+                args[0],
+                CallExp(Symbol("begin").withPos(args[0].pos), args.slice(1)).withPos(args[0].pos)
+            ]).withPos(args[0].pos);
+        };
 
         macros["cond"] = cond;
 

src/test/cases/BasicTestCase.hx

@@ -190,4 +190,8 @@ class BasicTestCase extends Test {
     function testLambda() {
         Assert.equals([5, 6].toString(), BasicTestCase.myFilteredList.toString());
     }
+
+    function testWhen() {
+        Assert.equals(6, BasicTestCase.myWhen1);
+    }
 }

src/test/cases/BasicTestCase.kiss

@@ -146,4 +146,6 @@
 
 (defvar myFilteredList (begin 
     (deflocal l [-1 -2 5 -3 6])
-    (l.filter (lambda [v] (< 0 v)))))
+    (l.filter (lambda [v] (< 0 v)))))
+
+(defvar myWhen1 (when true 5 6))