[past]: Add .closure() flag to PAST::Block to return closures with

captured outer context.

git-svn-id: https://svn.parrot.org/parrot/trunk@46600 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

compilers/pct/src/PAST/Compiler.pir

@@ -997,9 +997,18 @@ Return the POST representation of a C<PAST::Block>.
     bpost = $P0.'new'( bpost, 'node'=>node, 'result'=>blockreg)
     bpost.'push_pirop'( blockref, 'result'=>blockreg )
     unless islexical goto block_done
+    $I0 = node.'closure'()
+    if $I0 goto block_closure
     bpost.'push_pirop'('capture_lex', blockreg)
     goto block_done
 
+  block_closure:
+    ##  return a reference to a clone of the block with captured outer context
+    result = self.'uniquereg'('P')
+    bpost.'push_pirop'('newclosure', result, blockreg)
+    bpost.'result'(result)
+    goto block_done
+
   block_immediate:
     .local pmc arglist
     arglist = options['arglist']

compilers/pct/src/PAST/Node.pir

@@ -498,6 +498,21 @@ blocks in Perl6 C<if>, C<while>, and other similar statements).
 .end
 
 
+=item closure([value])
+
+Get/set the closure flag for the block to C<value>.  If set,
+any block reference returned by the node is to a clone of the
+block that has captured the current lexical context.
+
+=cut
+
+.sub 'closure' :method
+    .param pmc value           :optional
+    .param int has_value       :opt_flag
+    .tailcall self.'attr'('closure', value, has_value)
+.end
+
+
 =item control([value])
 
 Get/set the control exception handler for this block to C<value>.

docs/pdds/pdd26_ast.pod

@@ -481,13 +481,20 @@ the C<symbol> method below.
 =item blocktype([type])
 
 Get/set the type of the block to C<type>.  The currently
-understood values are 'declaration' and 'immediate'.  'Declaration'
-indicates that a block is simply being defined at this point, the
-result of the node is a reference to the block.  A C<blocktype>
-of 'immediate' indicates a block that is to be immediately
+understood values are 'declaration', 'immediate',  and 'method'.  
+'Declaration' indicates that a block is simply being defined at 
+this point, the result of the node is a reference to the block.  
+A C<blocktype> of 'immediate' indicates a block that is to be immediately
 executed when it is evaluated in the AST, and the result of the
 last operation is used as the return value for the block.
 
+=item closure([value])
+
+Get/set the closure flag for the block to C<value>.  If the closure
+flag on a (non-immediate) block is true, then the node returns a 
+reference to a clone of the block that has captured the current
+lexical context.
+
 =item namespace([value])
 
 Get/set the namespace for this particular block (and any nested