changing codegen for -n

adding QAST::Block

          - QAST::Stmts 
            - QAST::WVal(Array) 
            - QAST::Stmt 
              - QAST::Op(while) 
                - QAST::Op(p6definite) 
                  - QAST::Op(bind) 
                    - QAST::Var(lexical $_) 
                    - QAST::Op(call &get) 
                - QAST::Block(:blocktype(immediate)) 
                  - QAST::Stmts 
                    - QAST::Op(call &say) 
                      - QAST::Var(lexical $foobar) 
                    - QAST::WVal(Block)  :code_object<?> :past_block<?>
            - QAST::WVal(Nil)

AST before change

perl6-m --target=ast -ne ''
...
          - QAST::Stmts 
            - QAST::WVal(Array) 
            - QAST::Stmt 
              - QAST::Want 
                - QAST::Op(callmethod sink) 
                  - QAST::Op(callmethod map) 
                    - QAST::Op(call &lines) 
                    - QAST::Op(p6capturelex) 
                      - QAST::WVal(Block)  :code_object<?> :past_block<?>
                - v
                - QAST::Op(callmethod sink) 
                  - QAST::Op(callmethod map) 
                    - QAST::Op(call &lines) 
                    - QAST::Op(p6capturelex) 
                      - QAST::WVal(Block)  :code_object<?> :past_block<?>
            - QAST::WVal(Nil)

diff + AST after change

diff --git a/src/Perl6/Actions.nqp b/src/Perl6/Actions.nqp
index 3db4207..994375a 100644
--- a/src/Perl6/Actions.nqp
+++ b/src/Perl6/Actions.nqp
@@ -704,10 +704,16 @@ class Perl6::Actions is HLL::Actions does STDActions {
     # Turn $code into "for lines() { $code }"
     sub wrap_option_n_code($/, $code) {
         $code := make_topic_block_ref($/, $code, copy => 1);
-        my $past := QAST::Op.new(:op<callmethod>, :name<map>,
-            QAST::Op.new(:op<call>, :name<&lines>),
-            QAST::Op.new(:op<p6capturelex>, $code)
+        my $bind_stmts := QAST::Stmts.new(
+            QAST::Op.new(:op<bind>,
+                QAST::Var.new(:name<$_>, :scope<lexical>),
+                QAST::Op.new(:op<call>, :name<&get>))
         );
+        my $cond := QAST::Op.new(:op<p6definite>, $bind_stmts);
+        my $body := QAST::Op.new(:op<p6capturelex>, $code);
+        my $while := QAST::Op.new($cond, :op<while>, :node($/));
+        $while.push($body);
+        my $past := QAST::Stmts.new($while);
         $past := QAST::Want.new(
             QAST::Op.new( :op<callmethod>, :name<sink>, $past ),
             'v', QAST::Op.new( :op<callmethod>, :name<sink>, $past )

./perl6-m --target=ast -ne ''
...
          - QAST::Stmts 
            - QAST::WVal(Array) 
            - QAST::Stmt 
              - QAST::Want 
                - QAST::Op(callmethod sink) 
                  - QAST::Stmts 
                    - QAST::Op(while)  
                      - QAST::Op(p6definite) 
                        - QAST::Stmts 
                          - QAST::Op(bind) 
                            - QAST::Var(lexical $_) 
                            - QAST::Op(call &get) 
                      - QAST::Op(p6capturelex) 
                        - QAST::WVal(Block)  :code_object<?> :past_block<?>
                - v
                - QAST::Op(callmethod sink) 
                  - QAST::Stmts 
                    - QAST::Op(while)  
                      - QAST::Op(p6definite) 
                        - QAST::Stmts 
                          - QAST::Op(bind) 
                            - QAST::Var(lexical $_) 
                            - QAST::Op(call &get) 
                      - QAST::Op(p6capturelex) 
                        - QAST::WVal(Block)  :code_object<?> :past_block<?>
            - QAST::WVal(Nil)
            
# error if called with actual code to run
Cannot call method 'sink' on a null object
  in block <unit> at -e line 1

simplified changes, same error

diff --git a/src/Perl6/Actions.nqp b/src/Perl6/Actions.nqp
index 3db4207..6dae04c 100644
--- a/src/Perl6/Actions.nqp
+++ b/src/Perl6/Actions.nqp
@@ -701,21 +701,24 @@ class Perl6::Actions is HLL::Actions does STDActions {
         make $name;
     }
 
-    # Turn $code into "for lines() { $code }"
+    # Turn $code into "while ($_ := get()).DEFINITE { $code }"
     sub wrap_option_n_code($/, $code) {
         $code := make_topic_block_ref($/, $code, copy => 1);
-        my $past := QAST::Op.new(:op<callmethod>, :name<map>,
-            QAST::Op.new(:op<call>, :name<&lines>),
-            QAST::Op.new(:op<p6capturelex>, $code)
+        my $bind := QAST::Op.new(:op<bind>,
+            QAST::Var.new(:name<$_>, :scope<lexical>),
+            QAST::Op.new(:op<call>, :name<&get>)
         );
+        my $cond := QAST::Op.new(:op<p6definite>, $bind);
+        my $body := QAST::Op.new(:op<p6capturelex>, $code);
+        my $past := QAST::Op.new(:op<while>, $cond, $body);
         $past := QAST::Want.new(
             QAST::Op.new( :op<callmethod>, :name<sink>, $past ),
             'v', QAST::Op.new( :op<callmethod>, :name<sink>, $past )
         );
     }
 
-    # Turn $code into "for lines() { $code; say $_ }"
-    # &wrap_option_n_code already does the C<for> loop, so we just add the
+    # Turn $code into "while ($_ := get()).DEFINITE { $code; say $_ }"
+    # &wrap_option_n_code already does the C<while> loop, so we just add the
     # C<say> call here
     sub wrap_option_p_code($/, $code) {
         wrap_option_n_code($/,

./perl6-m --target=ast -ne ''
...
          - QAST::Stmts 
            - QAST::WVal(Array) 
            - QAST::Stmt 
              - QAST::Want 
                - QAST::Op(callmethod sink) 
                  - QAST::Op(while)  
                    - QAST::Op(p6definite) 
                      - QAST::Op(bind) 
                        - QAST::Var(lexical $_) 
                        - QAST::Op(call &get) 
                    - QAST::Op(p6capturelex) 
                      - QAST::WVal(Block)  :code_object<?> :past_block<?>
                - v
                - QAST::Op(callmethod sink) 
                  - QAST::Op(while)  
                    - QAST::Op(p6definite) 
                      - QAST::Op(bind) 
                        - QAST::Var(lexical $_) 
                        - QAST::Op(call &get) 
                    - QAST::Op(p6capturelex) 
                      - QAST::WVal(Block)  :code_object<?> :past_block<?>
            - QAST::WVal(Nil)

without Want

          - QAST::Stmts 
            - QAST::WVal(Array) 
            - QAST::Stmt 
              - QAST::Stmts 
                - QAST::Op(p6for)  
                  - QAST::Op(p6definite) 
                    - QAST::Stmts 
                      - QAST::Op(bind) 
                        - QAST::Var(lexical $_) 
                        - QAST::Op(call &get) 
                  - QAST::Op(p6capturelex) 
                    - QAST::WVal(Block)  :code_object<?> :past_block<?>
            - QAST::WVal(Nil)