Implement nonconstant strings in regexes

src/Niecza/Actions.pm

@@ -629,13 +629,23 @@ sub metachar__S_Single_Single { my ($cl, $M) = @_;
 
 sub metachar__S_Double_Double { my ($cl, $M) = @_;
     if (! $M->{quote}{_ast}->isa('Op::StringLiteral')) {
-        $M->sorry("Interpolating strings in regexes NYI");
+        $M->{_ast} = RxOp::VarString->new(value => $M->{quote}{_ast});
         return;
     }
     $M->{_ast} = RxOp::String->new(text => $M->{quote}{_ast}->text,
         igcase => $::RX{i}, igmark => $::RX{a});
 }
 
+sub metachar__S_var { my ($cl, $M) = @_;
+    if ($M->{quantified_atom}) {
+        $M->sorry("Explicit regex bindings NYI");
+        $M->{_ast} = RxOp::Sequence->new;
+        return;
+    }
+    $M->{_ast} = RxOp::VarString->new(value =>
+        $cl->do_variable_reference($M, $M->{variable}{_ast}));
+}
+
 sub rxcapturize { my ($cl, $name, $rxop) = @_;
     if (!$rxop->isa('RxOp::Subrule')) {
         # <before>, etc.  Not yet really handled XXX

src/RxOp.pm

@@ -59,6 +59,26 @@ use CgOp;
     no Moose;
 }
 
+{
+    package RxOp::VarString;
+    use Moose;
+    extends 'RxOp';
+
+    has value => (isa => 'Op', is => 'ro', required => 1);
+    sub opzyg { $_[0]->value }
+
+    sub code {
+        my ($self, $body) = @_;
+        CgOp::rxbprim('Exact', CgOp::unbox('str', CgOp::fetch(
+                    $self->value->cgop($body))));
+    }
+
+    sub lad { ['Imp'] }
+
+    __PACKAGE__->meta->make_immutable;
+    no Moose;
+}
+
 {
     package RxOp::Quantifier;
     use Moose;

test2.pl

@@ -5,6 +5,22 @@
 ok !('xy' ~~ /x <{ False }> y/), '<{False}> blocks a match';
 ok 'xy' ~~ /x <{ True }> y/, '<{True}> does not affect it';
 
+{
+    my $b = "oo";
+    is ("foox" ~~ /f$b/), "foo", '$x matches contents in a regex';
+
+    our role Stop4717[$a] {
+        token foo { $a }
+    }
+
+    grammar X {
+        token TOP { [ <foo> | foo ]: x }
+    }
+
+    ok (X but OUR::Stop4717["foobar"]).parse("foobarx"),
+        "LTM works through parameterized role variables";
+}
+
 #is $?FILE, 'test.pl', '$?FILE works';
 #is $?ORIG.substr(0,5), '# vim', '$?ORIG works';
 

v6/TODO

@@ -1,5 +1,3 @@
-~
-<?{ }>
 Cursor.add_categorical
 Cursor.alpha
 Cursor.canonicalize_name
@@ -19,6 +17,8 @@ Cursor.mixin
 Cursor.O
 Cursor.suppose
 Cursor.trim_heredoc
+Cursor.top_goal
+Highwater stuff
 EXPR will need a re-write with tests.
 $<foo> = 1
 func(|($key => $value))
@@ -32,10 +32,11 @@ self in regexes
 $<sym>
 temp $*FOO
 something with $*HIGHWATER, $*HIGHEXPECT, $*GOAL
-token { :my $var = expr; $var }
 token { $param-role-var }
 
 DONE:
+~
+<?{ }>
 circumfix:<[ ]>
 hash literals
 () being Nil
@@ -60,6 +61,7 @@ push(@array, $thing)
 shift(@array)
 &sort
 substr($str,$from,$len)
+token { :my $var = expr; $var }
 
 AVERTED: