working NFA example

nfa.pl

sub store_regex_alt_nfa($code_obj, $key, @alternatives) {
    my @saved;
    for @alternatives {
        @saved.push($_.save(:non_empty));
    }
    $code_obj.SET_ALT_NFA($key, @saved);
}

my $code_obj := nqp::create(NQPRegex);
my $ast :=  QAST::Regex.new(
                QAST::Regex.new( :rxtype<literal>, "xbc" ),
                QAST::Regex.new( :rxtype<literal>, "123" ),
                QAST::Regex.new( :rxtype<concat>,
                    QAST::Regex.new( :rxtype<literal>, "a"),
                    QAST::Regex.new( :rxtype<literal>, "b"),
                    QAST::Regex.new( :rxtype<literal>, "c"),
                ),
                QAST::Regex.new( :rxtype<concat>,
                    QAST::Regex.new( :rxtype<literal>, "x"),
                    QAST::Regex.new( :rxtype<literal>, "b"),
                    QAST::Regex.new( :rxtype<literal>, "c"),
                ),
                QAST::Regex.new( :rxtype<literal>, "456" ),
                QAST::Regex.new( :rxtype<literal>, "xb" ),
            );
my @alternatives;
for $ast.list {
    nqp::push(@alternatives, QRegex::NFA.new.addnode($_));
}
my $name := QAST::Node.unique('alt_nfa_') ~ '_' ~ ~nqp::time_n();
$ast.name($name);
store_regex_alt_nfa($code_obj, $ast.name, @alternatives);

my $nfa       := QRegex::NFA.new;
my @fates     := $nfa.states[0];
my int $start := 1;
my int $fate  := 0;
for $code_obj.ALT_NFA($name) {
    @fates[$fate] := $fate;
    $nfa.mergesubstates($start, 0, $fate, $_, self);
    $fate++;
}

say( $nfa.run( "xbc", 0 ) );

reduced.pl

my @nodes := [
                QAST::Regex.new( :rxtype<literal>, "xbc" ),
                QAST::Regex.new( :rxtype<literal>, "123" ),
                QAST::Regex.new( :rxtype<concat>,
                    QAST::Regex.new( :rxtype<literal>, "a"),
                    QAST::Regex.new( :rxtype<literal>, "b"),
                    QAST::Regex.new( :rxtype<literal>, "c"),
                ),
                QAST::Regex.new( :rxtype<concat>,
                    QAST::Regex.new( :rxtype<literal>, "x"),
                    QAST::Regex.new( :rxtype<literal>, "b"),
                    QAST::Regex.new( :rxtype<literal>, "c"),
                ),
                QAST::Regex.new( :rxtype<literal>, "456" ),
                QAST::Regex.new( :rxtype<literal>, "xb" ),
            ];

my $nfa       := QRegex::NFA.new;
my int $start := 1;
my int $fate  := 0;
for @nodes {
    $nfa.mergesubstates($start, 0, $fate, QRegex::NFA.new.addnode( $_ ).save( :non_empty ), self);
    $fate++;
}

say( $nfa.run( "xbc", 0 ) );