Start saving per-alternation NFAs.

Author: jnthn

src/QRegex/P6Regex/Actions.nqp

@@ -519,6 +519,7 @@ class QRegex::P6Regex::Actions is HLL::Actions {
                                 :hll<nqp>, :namespace(['Sub']), :lexical(0),
                                 :name($block.subid ~ '_nfa'), $nfapast);
             $initpast.push(PAST::Stmt.new($nfablock));
+        alt_nfas($qast, $block.subid, $initpast);
         }
 
         unless $block.symbol('$¢') {
@@ -586,6 +587,28 @@ class QRegex::P6Regex::Actions is HLL::Actions {
         %capnames{''} := $count;
         %capnames;
     }
+    
+    sub alt_nfas($ast, $subid, $initpast) {
+        my $rxtype := $ast.rxtype;
+        if $rxtype eq 'alt' {
+            my $nfapast := PAST::Op.new( :pasttype('list') );
+            $ast.name(PAST::Node.unique('alt_nfa_'));
+            for $ast.list {
+                alt_nfas($_, $subid, $initpast);
+                $nfapast.push(QRegex::NFA.new.addnode($_).past);
+            }
+            my $nfablock := PAST::Block.new(
+                                :hll<nqp>, :namespace(['Sub']), :lexical(0),
+                                :name($subid ~ '_' ~ $ast.name), $nfapast);
+            $initpast.push(PAST::Stmt.new($nfablock));
+        }
+        elsif $rxtype eq 'subcapture' || $rxtype eq 'quant' {
+            alt_nfas($ast[0], $subid, $initpast)
+        }
+        elsif $rxtype eq 'concat' || $rxtype eq 'altseq' || $rxtype eq 'conj' || $rxtype eq 'conjseq' {
+            for $ast.list { alt_nfas($_, $subid, $initpast) }
+        }
+    }
 
     method subrule_alias($ast, $name) {
         if $ast.name gt '' { $ast.name( $name ~ '=' ~ $ast.name ); }