From b0cd2b8f32315ecf54dc1a3cfe831e40b0edeb3b Mon Sep 17 00:00:00 2001
From: pmichaud <pmichaud@pobox.com>
Date: Wed, 7 Jul 2010 02:02:56 -0500
Subject: [PATCH] Add a $MAIN parameter to unit mainline (signals that the unit
 is the mainline).

---
 src/Perl6/Actions.pm | 19 +++++++++++++------
 src/core/MAIN.pm     |  4 ++--
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/Perl6/Actions.pm b/src/Perl6/Actions.pm
index a321f51880c..ab06f7ff8d3 100644
--- a/src/Perl6/Actions.pm
+++ b/src/Perl6/Actions.pm
@@ -51,7 +51,6 @@ method comp_unit($/, $key?) {
     # Get the block for the unit mainline code.
     my $unit := @BLOCK.shift;
     my $mainline := $<statementlist>.ast;
-    $unit.push($mainline);
 
     # Get the block for the entire compilation unit.
     my $outer := @BLOCK.shift;
@@ -60,26 +59,34 @@ method comp_unit($/, $key?) {
     
     # If it's the setting, just need to run the mainline.
     if $*SETTING_MODE {
+        $unit.push($mainline);
         $unit.hll($?RAKUDO_HLL);
         $unit.pirflags(':init :load');
         make $unit;
         return 1;
     }
 
+    my $mainparam := PAST::Var.new(:name('$MAIN'), :scope('parameter'),
+                         :viviself( PAST::Val.new( :value(0) ) ) );
+    $unit.symbol('$MAIN', :scope<lexical>);
     # run MAIN subs
     # TODO: run this only when not in a module
     # TODO: find a less hacky solution than IN_EVAL
     # TODO: find a way to inject MAIN_HELPER call without modifying
     # the return value of the compilation unit
     if !IN_EVAL() && $unit.symbol('&MAIN') {
-        $unit.push(
+        $mainline := 
             PAST::Op.new(
                 :pasttype('call'),
-                :name('&MAIN_HELPER')
-            )
-        );
+                :name('&MAIN_HELPER'),
+                $mainline,
+                $mainparam
+            );
     }
-
+    else {
+        $unit.push($mainparam);
+    }
+    $unit.push($mainline);
 
     # Executing the compilation unit causes the mainline to be executed.
     # We force a tailcall here, because we have other :load/:init blocks
diff --git a/src/core/MAIN.pm b/src/core/MAIN.pm
index ae0561a91c7..0fef7be6170 100644
--- a/src/core/MAIN.pm
+++ b/src/core/MAIN.pm
@@ -1,4 +1,4 @@
-our sub MAIN_HELPER() {
+our sub MAIN_HELPER($retval, $MAIN?) {
     my $m = Q:PIR {
         $P0 = getinterp
         $P0 = $P0['lexpad';1]
@@ -11,7 +11,7 @@ our sub MAIN_HELPER() {
     done:
     };
     unless $m {
-        return;
+        return $retval;
     }
     
     # We found MAIN, let's process the command line arguments accordingly