implement while/until/repeat_while/repeat_until without using labels/…

…gotos :/

lua/compiler/LST.pm

@@ -299,6 +299,43 @@ class LST::If is LST::Node {
     }
 }
 
+class LST::While is LST::Node {
+    has $!type;
+    has $!bool;
+    has $!result;
+    has $!repeat;
+
+    method bool($set?) {
+        if $set { $!bool := $set }
+        $!bool
+    }
+
+    method type($set?) {
+        if $set { $!type := $set }
+        $!type
+    }
+
+    method result($set?) {
+        if $set { $!result := $set }
+        $!result
+    }
+
+    method repeat($set?) {
+        if pir::defined($set) { $!repeat := $set }
+        $!repeat
+    }
+
+    method new(:$bool, :$type, :$result, :$repeat, *@children) {
+        my $obj := self.CREATE;
+        $obj.set_children(@children);
+        $obj.bool($bool);
+        $obj.repeat($repeat);
+        $obj.type(pir::defined($type) ?? $type !! 'RakudoObject');
+        $obj.result(pir::defined($result) ?? $result !! 1);
+        $obj;
+    }
+}
+
 class LST::Return is LST::Node {
     has $!target;
 

lua/compiler/LST2Lua.pm

@@ -212,6 +212,39 @@ our multi sub cs_for(LST::If $if) {
     return $code;
 }
 
+our multi sub cs_for(LST::While $while) {
+    unless +@($while) == 3 { pir::die('A LST::While node must have 3 children') }
+
+    # Need a variable to put the final result in.
+    my $while_result := get_unique_id('while_result') if $while.result;
+
+    # Get the conditional and emit while.
+    my $cond_code := cs_for((@($while))[0]) ~ cs_for((@($while))[1]);
+    # $*LAST_TEMP is set by the condition result cs_for regardless of 
+    #   whether the condition code is emitted at the beginning of the loop
+
+    my $code := $while.repeat ?? "" !! $cond_code;
+
+    $code := $code ~
+             "        $while_result = nil;\n" if $while.result;
+    if ($while.repeat) {
+        $code := $code ~
+             "        $*LAST_TEMP = " ~ ($while.bool ?? "true" !! 1) ~ ";\n";
+    }
+    $code := $code ~
+             "        while ($*LAST_TEMP" ~ ($while.bool ?? "" !! " ~= 0") ~ ") do\n";
+
+    # Compile branch.
+    $*LAST_TEMP := 'nil';
+    $code := $code ~ cs_for((@($while))[2]);
+    $code := $code ~ "        $while_result = $*LAST_TEMP;\n" if $while.result;
+    $code := $code ~ $cond_code;
+    $code := $code ~ "        end\n";
+
+    $*LAST_TEMP := $while_result if $while.result;
+    return $code;
+}
+
 our multi sub cs_for(LST::Return $ret) {
     return cs_for($ret.target) ~ "        return " ~ $*LAST_TEMP ~ ";\n";
 }

lua/compiler/PAST2LSTCompiler.pm

@@ -692,9 +692,6 @@ our multi sub lst_for(PAST::Op $op) {
     }
 
     elsif $op.pasttype eq 'while' || $op.pasttype eq 'until' {
-        # Need labels for start and end.
-        my $test_label := get_unique_id('while_lab');
-        my $end_label := get_unique_id('while_end_lab');
         my $cond_result := LST::Local.new( :name(get_unique_id('cond')) );
 
         # Compile the condition.
@@ -716,26 +713,15 @@ our multi sub lst_for(PAST::Op $op) {
         my $body := lst_for((@($op))[1]);
 
         # Build up result.
-        return LST::Stmts.new(
-            LST::Label.new( :name($test_label) ),
+        return LST::While.new(
+            :repeat(0),
             $cond,
-            LST::If.new(
-                unbox('int', $cond_result),
-                $body,
-                LST::Stmts.new(
-                    $cond_result,
-                    LST::Goto.new( :label($end_label) )
-                )
-            ),
-            LST::Goto.new( :label($test_label) ),
-            LST::Label.new( :name($end_label) )
+            unbox('int', $cond_result),
+            $body
         );
     }
 
     elsif $op.pasttype eq 'repeat_while' || $op.pasttype eq 'repeat_until' {
-        # Need labels for start and end.
-        my $test_label := get_unique_id('while_lab');
-        my $block_label := get_unique_id('block_lab');
         my $cond_result := LST::Local.new( :name(get_unique_id('cond')) );
 
         # Compile the condition.
@@ -757,17 +743,11 @@ our multi sub lst_for(PAST::Op $op) {
         my $body := lst_for((@($op))[1]);
 
         # Build up result.
-        return LST::Stmts.new(
-            LST::Label.new( :name($block_label) ),
-            $body,
+        return LST::While.new(
+            :repeat(1),
             $cond,
-            LST::If.new(
-                unbox('int', $cond_result),
-                LST::Stmts.new(
-                    $cond_result,
-                    LST::Goto.new( :label($block_label) )
-                )
-            )
+            unbox('int', $cond_result),
+            $body
         );
     }
 

lua/compiler/try.bat

@@ -1,8 +1,10 @@
 @if exist x.exe del /Q x.exe
 @if exist x.cs del /Q x.cs
 @nmake /nologo P6Objects.dll >NUL
-@parrot compile.pir %1 > x.cs
-@csc /nologo x.cs /reference:RakudoRuntime.dll /debug /warn:0
+echo --> x.lua
+rem @type RakudoRuntime.lua > x.lua
+rem @type NQPSetting.lua >> x.lua
+rem @type P6Objects.lua >> x.lua
+@parrot compile.pir %1 >> x.lua
 @echo ---
-@x
-
+@luajit x.lua