#!/usr/bin/perl --
use strict; use warnings; use Data::Dump;
my $jp = do {
    use Regexp::Grammars;
qr{
# Keep the big stick handy, just in case...
#~ <debug:on>
 
# Match this...
^ <object> | <array> $


<token: JSON_text>
  <object> | <array>

<token: begin_array>
  (?: <ws>\x5B<ws> )

<token: begin_object>
  (?: <ws>\x7B<ws> )

<token: end_array>
  (?: <ws>\x5D<ws> )

<token: end_object>
  (?: <ws>\x7D<ws> )

<token: name_separator>
  (?: <ws>\x3A<ws> )

<token: value_separator>
  (?: <ws>\x2C<ws> )

<token: ws>
   (?: \x20 | \x09 | \x0A | \x0D )* 

<token: value>
  <false> | <null> | <true> | <object> | <array> | <number> | <string>

<token: false>
  \x66\x61\x6c\x73\x65

<token: null>
  \x6e\x75\x6c\x6c

<token: true>
  \x74\x72\x75\x65

<token: object>
  (?: <begin_object> (?: (?: <member> (?: (?: <value_separator><member> ) )*  ) )? <end_object> )

<token: member>
  (?: <string><name_separator><value> )

<token: array>
  (?: <begin_array> (?: (?: <value> (?: (?: <value_separator><value> ) )*  ) )? <end_array> )

<token: number>
  (?:  (?: <minus> )? <int> (?: <frac> )?  (?: <exp> )?  )

<token: decimal_point>
  \x2E

<token: digit1_9>
  [\x{31}-\x{39}]

<token: e>
  \x65 | \x45

<token: exp>
  (?: <e> (?: <minus> | <plus> )?  (?: <DIGIT> )+  )

<token: frac>
  (?: <decimal_point> (?: <DIGIT> )+  )

<token: int>
  <zero> | (?: <digit1_9> (?: <DIGIT> )*  )

<token: minus>
  \x2D

<token: plus>
  \x2B

<token: zero>
  \x30

<token: string>
  (?: <quotation_mark> (?: <char> )* <quotation_mark> )

<token: char>
  <unescaped> | (?: <escape>\x22 | \x5C | \x2F | \x62 | \x66 | \x6E | \x72 | \x74 | (?: \x75 (?: <HEXDIG> ){4}  ) )

<token: escape>
  \x5C

<token: quotation_mark>
  \x22

<token: unescaped>
  [\x{20}-\x{21}] | [\x{23}-\x{5B}] | [\x{5D}-\x{10FFFF}]

<token: HEXDIG>
  <DIGIT> | A | B | C | D | E | F

<token: DIGIT>
  [\x{30}-\x{39}]

}ixs};
for my $str( q/[false,true,null]/ , ){
    print "#<<@{[time-$^T]}#  $str  \n";
    if( $str =~ $jp ){
        dd(\%/) ; #/
    } else {
        print "## fail to match \n";
    }
    print "#>>@{[time-$^T]}#\n";
}