Implement multi-variable for

TODO

@@ -37,8 +37,6 @@ MEDIUM
 
  + &hyperunary
 
- + for-loops with multiple parameters
-
    Implement your favorite ?-vars.
 
    Finish the set of Num operators, includig number-theoretic and

src/niecza

@@ -28,6 +28,40 @@ use OptRxSimple;
 use STD;
 use Sig;
 
+augment class Op::ForLoop { #OK exist
+    method statement_level() {
+        my $var = [ map { ::GLOBAL::NieczaActions.gensym },
+            0 ..^ +$.sink.body.signature.params ];
+        $.sink.once = True;
+        ::Op::ImmedForLoop.new(source => $.source, var => $var,
+            sink => ::Op::CallSub.new(invocant => $.sink,
+                positionals => [ map { ::Op::LetVar.new(name => $_) }, @$var]));
+    }
+}
+
+augment class Op::ImmedForLoop { #OK exist
+    method code_labelled($body, $l) {
+        my $id = ::GLOBAL::NieczaActions.genid;
+
+        CgOp.rnull(CgOp.letn(
+            "!iter$id", CgOp.vvarlist_new_empty,
+            (map { $_, CgOp.null('var') }, @$.var),
+            CgOp.vvarlist_push(CgOp.letvar("!iter$id"),
+                $.source.cgop($body)),
+            CgOp.whileloop(0, 0,
+                CgOp.iter_hasflat(CgOp.letvar("!iter$id")),
+                CgOp.prog(
+                    (map { CgOp.letvar($_,
+                        CgOp.vvarlist_shift(CgOp.letvar("!iter$id")))},@$.var),
+                    CgOp.sink(CgOp.xspan("redo$id", "next$id", 0,
+                        $.sink.cgop($body),
+                        1, $l, "next$id",
+                        2, $l, "last$id",
+                        3, $l, "redo$id")))),
+            CgOp.label("last$id")));
+    }
+}
+
 augment class CgOp {
 }
 

test2.pl

@@ -13,6 +13,10 @@
     is +[ Foo.new(bar => (1,2,4)).bar ], 3, '@.bar initializes with list context';
     is +[ Foo.new(bar => 5).bar ], 1, '@.bar can initialize from a single item';
     is +[ Foo.new.quux ], 3, '@.quux with init list works';
+
+    my $str = '';
+    for 1,2,3,4 -> $x, $y { $str ~= "$x|$y," }
+    is $str, "1|2,3|4,", 'multivariable for works';
 }
 
 #is $?FILE, 'test.pl', '$?FILE works';