whileLet

src/kiss/Macros.hx

@@ -748,6 +748,18 @@ class Macros {
 
         macros["awaitLet"] = awaitLet;
         
+        macros["whileLet"] = (wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) -> {
+            wholeExp.checkNumArgs(2, null, "(whileLet [<bindings...>] <body...>)");
+            var b = wholeExp.expBuilder();
+            return b.callSymbol("loop", [
+                b.callSymbol("ifLet", [
+                    exps[0],
+                        b.begin(exps.slice(1)),
+                    b.callSymbol("break", [])
+                ])
+            ]);
+        };
+
         // TODO test defNew
         macros["defnew"] = (wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) -> {
             wholeExp.checkNumArgs(1, null, "(defNew [[args...]] [[optional property bindings...]] [optional body...]");

src/test/cases/BasicTestCase.hx

@@ -4,6 +4,7 @@ import utest.Test;
 import utest.Assert;
 import kiss.Prelude;
 import kiss.List;
+import kiss.Stream;
 import haxe.ds.Option;
 
 using StringTools;
@@ -341,6 +342,10 @@ class BasicTestCase extends Test {
     function testIntersect() {
         _testIntersect();
     }
+
+    function testWhileLet() {
+        _testWhileLet();
+    }
 }
 
 class BasicObject {

src/test/cases/BasicTestCase.kiss

@@ -629,3 +629,11 @@
         (assert (contains intersection3d "cy3"))
         )
     (Assert.pass))
+
+(function _testWhileLet []
+    (let [&mut idx 0
+            lines ["a" "b" "c"]
+            stream (Stream.fromString "a\nb\nc")]
+        (whileLet [(Some line) (stream.takeLine)]
+            (Assert.equals (nth lines idx) line)
+            (+= idx 1))))