double-quotes-escapeding.pl

use 5.018;
use strictures;

use Marpa::R2 qw();
use DDS; 

my $source = <<'END';
:default ::=
    action => [values]
    bless  => ::lhs
lexeme default =
    action => [ value ]
    bless  => ::name
    latm   => 1
 
:start              ::= escapedstring
escapedstring       ::= '"' stringbody '"'
stringbody          ::= stringbodychar*
stringbodychar      ~ [^\\"] | escapedquote
escapedquote        ~ '\"'
END
 
my $grammar = Marpa::R2::Scanless::G->new({
    bless_package => 'Quot',
    source        => \$source,
});

for my $in (
    qq("foo\N{REVERSE SOLIDUS}"bar"), 
    q("foo\N{REVERSE SOLIDUS}"bar"), 
    qq("foo\"bar"),
    q("foo\"bar"), 
    ){
    say "\nInput: ", $in;
    my $parser = Marpa::R2::Scanless::R->new({
        grammar => $grammar,
    });
    eval {
        $parser->read( \$in );
    };
    if ($@){    
        say "Parse failed!"
    }
    else{
        DumpLex ${$parser->value};
    }
}

Input: "foo\"bar"
$Quot_escapedstring1 = bless( [
                         '"',
                         bless( [
                           bless( [ 'f' ], 'Quot::stringbodychar' ),
                           bless( [ 'o' ], 'Quot::stringbodychar' ),
                           bless( [ 'o' ], 'Quot::stringbodychar' ),
                           bless( [ '\\"' ], 'Quot::stringbodychar' ),
                           bless( [ 'b' ], 'Quot::stringbodychar' ),
                           bless( [ 'a' ], 'Quot::stringbodychar' ),
                           bless( [ 'r' ], 'Quot::stringbodychar' )
                         ], 'Quot::stringbody' ),
                         '"'
                       ], 'Quot::escapedstring' );

Input: "foo\N{REVERSE SOLIDUS}"bar"
Parse failed!

Input: "foo"bar"
Parse failed!

Input: "foo\"bar"
$Quot_escapedstring1 = bless( [
                         '"',
                         bless( [
                           bless( [ 'f' ], 'Quot::stringbodychar' ),
                           bless( [ 'o' ], 'Quot::stringbodychar' ),
                           bless( [ 'o' ], 'Quot::stringbodychar' ),
                           bless( [ '\\"' ], 'Quot::stringbodychar' ),
                           bless( [ 'b' ], 'Quot::stringbodychar' ),
                           bless( [ 'a' ], 'Quot::stringbodychar' ),
                           bless( [ 'r' ], 'Quot::stringbodychar' )
                         ], 'Quot::stringbody' ),
                         '"'
                       ], 'Quot::escapedstring' );