[nqp]: Add code assertions to nqp.

src/NQP/Actions.pm

@@ -369,6 +369,8 @@ method regex_declarator($/, $key?) {
             $P0 = find_lex '$name'
             set_hll_global ['Regex';'P6Regex';'Actions'], '$REGEXNAME', $P0
         };
+        @BLOCK[0].symbol('$¢', :scope('lexical'));
+        @BLOCK[0].symbol('$/', :scope('lexical'));
         return 0;
     }
     elsif $<proto> {
@@ -557,4 +559,29 @@ class NQP::RegexActions is Regex::P6Regex::Actions {
         make PAST::Regex.new( $past, :pasttype('pastnode') );
     }
 
+    method metachar:sym<{ }>($/) { make $<codeblock>.ast; }
+
+    method assertion:sym<{ }>($/) { make $<codeblock>.ast; }
+
+    method codeblock($/) {
+        my $block := $<block>.ast;
+        $block.blocktype('immediate');
+        my $past := 
+            PAST::Regex.new(
+                PAST::Stmts.new(
+                    PAST::Op.new(
+                        PAST::Var.new( :name('$/') ),
+                        PAST::Op.new(
+                            PAST::Var.new( :name('$¢') ),
+                            :name('MATCH'),
+                            :pasttype('callmethod')
+                        ),
+                        :pasttype('bind')
+                    ),
+                    $block
+                ),
+                :pasttype('pastnode')
+            );
+        make $past;
+    }
 }

src/NQP/Grammar.pm

@@ -371,4 +371,16 @@ grammar NQP::Regex is Regex::P6Regex::Grammar {
     token metachar:sym<:my> { 
         ':' <?before 'my'> <statement=LANG('MAIN', 'statement')> <.ws> ';' 
     }
+
+    token metachar:sym<{ }> {
+        <?[{]> <codeblock>
+    }
+
+    token assertion:sym<{ }> {
+        <?[{]> <codeblock>
+    }
+
+    token codeblock {
+        <block=LANG('MAIN','pblock')>
+    }
 }

src/PAST/Compiler-Regex.pir

@@ -127,6 +127,8 @@ Return the POST representation of the regex AST rooted by C<node>.
   caparray_skip:
 
     ops.'push_pirop'('.lex', 'unicode:"$\x{a2}"', cur)
+    ops.'push_pirop'('.local pmc', 'match')
+    ops.'push_pirop'('.lex', '"$/"', 'match')
     ops.'push_pirop'('length', eos, tgt, 'result'=>eos)
 
     # On Parrot, indexing into variable-width encoded strings 
@@ -735,8 +737,25 @@ second child of this node.
 
 .sub 'pastnode' :method :multi(_, ['PAST';'Regex'])
     .param pmc node
-    $P0 = node[0]
-    .tailcall self.'as_post'($P0)
+    .local pmc cur, pos, fail, ops
+    (cur, pos, fail) = self.'!rxregs'('cur pos fail')
+    ops = self.'post_new'('Ops', 'node'=>node, 'result'=>cur)
+
+    .local pmc cpast, cpost
+    cpast = node[0]
+    cpost = self.'as_post'(cpast, 'rtype'=>'P')
+
+    self.'!cursorop'(ops, '!cursor_pos', 0, pos)
+    ops.'push'(cpost)
+
+    .local pmc subtype, negate, testop
+    subtype = node.'subtype'()
+    if subtype != 'zerowidth' goto done
+    negate = node.'negate'()
+    testop = self.'??!!'(negate, 'if', 'unless')
+    ops.'push_pirop'(testop, cpost, fail)
+  done:
+    .return (ops)
 .end