[nrx] Expose backtracking and labels to cgop

src/CgOp.pm

@@ -576,6 +576,24 @@ use warnings;
             zyg => [ $inv, @args ], is_cps_call => 1);
     }
 
+    sub label {
+        my ($name) = @_;
+        CgOp::Primitive->new(op => [ 'labelhere', $name ],
+            zyg => [ ], is_cps_call => 1);
+    }
+
+    sub goto {
+        my ($name) = @_;
+        CgOp::Primitive->new(op => [ 'goto', $name ],
+            zyg => [ ], is_cps_call => 1);
+    }
+
+    sub rxpushb {
+        my ($tag, $lbl) = @_;
+        CgOp::Primitive->new(op => [ 'rxpushb', $tag, $lbl ],
+            zyg => [ ], is_cps_call => 1);
+    }
+
     sub rxbprim {
         my ($name, @args) = @_;
         CgOp::Primitive->new(op => [ 'rxbprim', $name, scalar @args ],

src/CodeGen.pm

@@ -621,6 +621,12 @@ use 5.010;
         $self->_emit("if (!th.rx.$name(" . join(", ", @args) . ")) return th.rx.Backtrack(th)");
     }
 
+    sub rxpushb {
+        my ($self, $tag, $label) = @_;
+        push @{ $self->buffer }, "    th.rx.PushBacktrack(" . qm($tag) .
+            ", \@\@L$label);\n";
+    }
+
     sub return {
         my ($self, $nv) = @_;
         return if $self->unreach;
@@ -738,7 +744,7 @@ use 5.010;
                 ($self->numlets + $self->minlets - 4), "];\n";
         }
         for (@{ $self->buffer }) {
-            s/\@\@L(\d+)/$self->labelname->{$1}/eg;
+            s/\@\@L(\w+)/$self->labelname->{$1}/eg;
         }
         print ::NIECZA_OUT " " x 12, $_ for @{ $self->buffer };
         print ::NIECZA_OUT " " x 12, "default:\n";

test2.pl

@@ -7,7 +7,12 @@ ($C)
     Q:CgOp {
         (prog
           (setfield rx (callframe) (rawnew RxFrame (cast Cursor (@ {$C}))))
+          (rxpushb SEQALT b1)
           (rxbprim ExactOne (char x))
+          (goto b2)
+          (label b1)
+          (rxbprim ExactOne (char y))
+          (label b2)
           (rawccall (getfield rx (callframe)) End)
           (rawccall (getfield rx (callframe)) Backtrack)
           (null Variable))
@@ -27,7 +32,8 @@ ($C)
     }
 }
 
-is +rxt(Cursor.new("x")), 1, "/x/ ~~ x";
-is +rxt(Cursor.new("y")), 0, "/x/ !~ y";
+is +rxt(Cursor.new("x")), 1, "/x||y/ ~~ x";
+is +rxt(Cursor.new("y")), 1, "/x||y/ ~~ y";
+is +rxt(Cursor.new("z")), 0, "/x||y/ !~~ z";
 
 done-testing;