Image

head

code

root

para

L<Examples| file:../examples/index.podlite>


L<Download |file:../download/index.podlite>


React

=begin React :component<HeaderCol> :id<menu> 
=para L<Documentation|/doc/introduction>
=para L<Modules| /mods>
=para L<Examples| file:../examples/index.podlite>
=para L<Download |file:../download/index.podlite>
=para L<About|file:../about/index.podlite>
=para 🔍 K<⌘K>/K<ctrl-K>
=end React


HEADER

FOOTER

README

use nqp;
use QAST:from<NQP>;

# This feels like something of a cheat, because I should be able to do it
# directly at the NQP level. But this method works for now.
#
# The short version: Slang::Roman::to-number takes the value it's given and
# returns a Roman numeral representing it.
#
# The Roman::Grammar and Roman::Actions are spliced into the running Perl 6
# grammar and augment the existing <number> type to include my <romanint>
# token.
#
# Roman::Grammar contains the token and related rule.
#
# Roman::Actions is where the fun starts, read that code for more explanation.
#

sub to-roman (Int $val) is export
  {
  my $current = $val;
  my $roman = '';
  my %num-map =
    (
    1 => 'I',
    5 => 'V',
    10 => 'X',
    50 => 'L',
    100 => 'C',
    500  => 'D',
    1_000 => 'M',
    5_000 => '\c[0x2181]',
    10_000 => '\c[0x2182]',
    50_000 => '\c[0x2187]',
    100_000 => '\c[0x2188]'
    );

  for %num-map.keys.sort: { $^b <=> $^a } -> $value
    {
    while ($value <= $current)
      {
      $current -= $value;
      $roman ~= %num-map{$value};
      }
    }
  return $roman;
  }

sub Slang::Roman::to-number(Str $value) is export
  {
  my %char-map =
    (
    I => 1, "\c[0x2160]" => 1,
            "\c[0x2161]" => 2,
            "\c[0x2162]" => 3,
            "\c[0x2163]" => 4,
    V => 5, "\c[0x2164]" => 5,
            "\c[0x2165]" => 6,
            "\c[0x2166]" => 7,
            "\c[0x2167]" => 8,
            "\c[0x2168]" => 9,
    X => 10, "\c[0x2169]" => 10,
             "\c[0x216a]" => 11,
             "\c[0x216b]" => 12,
    L => 50, "\c[0x216c]" => 50,
    C => 100, "\c[0x216d]" => 100,
    D => 500, "\c[0x216e]" => 500,
    M => 1_000, "\c[0x216f]" => 1_000,
                "\c[0x2180]" => 1_000, # C D
                "\c[0x2181]" => 5_000,
                "\c[0x2182]" => 10_000,
                # claudian antisigma
                #\c[0x2183] # ROMAN NUMERAL REVERSED ONE HUNDRED
                "\c[0x2187]" => 50_000,
                "\c[0x2188]" => 100_000,
    );
  my $num = $value;
  $num ~~ s/^0r//;

  # Find subtractives and convert them to additives
  #
  # IV => IIII ( 5 - 1 == 4 )
  # IX => VIIII ( 10 - 1 == 9 )
  # XL => XXXX ( 50 - 10 == 40 )
  # IL => XXXXVIIII ( 50 - 1 == 49 )
  # XC => LXXXX ( 100 - 10 == 90 )
  # CD => CCCC ( 500 - 100 == 400 )
  # CM => DCCCC ( 1000 - 100 == 900 )

  $num ~~ s:g/
    (<[
    I \c[0x2160]
    X \c[0x2169]
    C \c[0x216d]
    M \c[0x216f]
      \c[0x2182]
    ]>)
    (<[
    V \c[0x2164]
    X \c[0x2169]
    L \c[0x216c]
    C \c[0x216d]
    D \c[0x216e]
    M \c[0x216f]
      \c[0x2181]
      \c[0x2182]
      \c[0x2187]
      \c[0x2188]
    ]>)
    / {
      my $x = ( %char-map{$0} < %char-map{$1} )
      ?? to-roman ( %char-map{$1} - %char-map{$0} )
      !! ( $0 ~ $1 );
      $x;
    } /;

  my @chars = $num.split('');

  # Additive only for now...
  #
  my Int $final-value = 0;
  for @chars -> $x
    {
    next unless %char-map{$x}:exists;
    $final-value += %char-map{$x};
    }
  $final-value;
  }

sub EXPORT(|)
  {
  role Roman::Grammar
    {
    # Patch the <number> rule to add our own numeric type.
    #
    # This gets bound to a grammar action at runtime, so that we can capture
    # the string.
    #
    rule number:sym<roman>
      { <romanint> }

    # Describes a Roman number. Note that this includes the full Unicode range
    # of valid numbers - 1 .. 12 are there because some countries use formats
    # like '25-XII-2015' to represent Christmas, and they use the Unicode
    # roman numerals to fit in to forms.
    #
    token romanint
      { '0r' <[ I V X L C D M \c[0x2160] .. \c[0x2183] \c[0x2187] \c[0x2188] ]>+
      }
    }

  role Roman::Actions
    {
    sub lk(Mu \h, \k)
      { nqp::atkey(nqp::findmethod(h, 'hash')(h), k) }

    # This is called at compile-time, and replaces the '0rIIII' in the input
    # with a function call which converts the Roman numeral to its decimal
    # equivalent.
    #
    method number:sym<roman>(Mu $/)
      {
      my $number   := lk($/, 'romanint');
      my $block := QAST::Op.new(
                     :op<call>,
                     :name<&Slang::Roman::to-number>,
                     QAST::SVal.new(:value($number.Str))
                   );
      $/.make($block);
      }
    }

  # Patch the running grammar with our Grammar and Actions roles.
  #
  $*LANG.define_slang(
    'MAIN',
    $*LANG.slang_grammar('MAIN').^mixin(Roman::Grammar),
    $*LANG.slang_actions('MAIN').^mixin(Roman::Actions),
  );

  {}
  }



Slang::Roman - lets you use Roman numerals in your code


=begin code :lang<raku>

use Slang::Roman;

say 0rI + 0rIX; # 10
my $i = 0rMMXVI; # $i = 2016

=end code


This bit of admittedly twisted code let you use Roman numerals in your Perl 6 code. It patches the running grammar so you can use a Roman numeral anywhere you would use a regular integer.


Future enhancements will include expansions to printf/sprintf with a custom formatting type, and the equivalents of C<hex()> to handle string conversion.


While it handles both additive and subtractive Roman numerals, it doesn't check that they're properly formatted. For instance 'IC' should be a compile-time error but instead it'll generate 101 as if nothing of consequence happened.


Source can be located at: https://github.com/raku-community-modules/Slang-Roman .
Comments and Pull Requests are welcome.


This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.


Roman

my role Piersing {
    token identifier {
        <.ident> [ <.apostrophe> <.ident> ]* <[?!]>?
    }

    token name {
        [
          | <identifier> <morename>*
          | <morename>+
        ]
        <[?!]>?
    }
}

use Slangify Piersing, Mu;



Slang::Piersing - allow ? and ! at end of identifiers


=begin code :lang<raku>

use Slang::Piersing;

sub foo?($a, $b) { $a * $b };
sub foo!($a, $b) { $a + $b };

foo? 3, 5  # 15
foo?(3, 5) # 15
foo!(3, 5) #  8

=end code


The C<Slang::Piersing> module adapts the Raku Programming Language
syntax to allow the question mark C<?> and exclamation mark C<!> at
the end of identifiers.


Source can be located at: https://github.com/raku-community-modules/Slang-Piersing .
Comments and Pull Requests are welcome.


Piersing

The Raku Knowledge Base


=begin React :component<HeaderCol> :id<footer>  
=begin nested :!nested
=item1 B<Language>
    =item2 L<Get started|file:../getting-started/getting-started.podlite>
    =item2 L<Why Raku?|/doc/language/faq#Why-should-I-learn-Raku-What's-so-great-about-it>
    =item2 L<Try Raku|https://glot.io/new/raku>
    =item2 L<Raku cheat sheet|https://github.com/Raku/mu/blob/master/docs/Perl6/Cheatsheet/cheatsheet.txt>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<Raku on Exercism|https://exercism.org/tracks/raku>
    =item2 L<Wikipedia|https://en.wikipedia.org/wiki/Raku_(programming_language)>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>

=end nested
=begin nested :!nested

=item1 B<L<Documentation|/doc>>
    =item2 L<Getting started, Migration guides from other languages, & Tutorials | file:../doc/introduction.podlite>
    =item2 L<Language References|file:../doc/reference.podlite>
    =item2 L<Type Reference| file:../doc/types.podlite>
    =item2 L<Miscellaneous| file:../doc/miscellaneous.podlite>
    =item2 L<FAQs (Frequently Asked Questions)|/doc/language/faq>
    =item2 L<Community|/doc/language/community>
    =item2 L<The list of all documents|file:../doc/index.podlite>

=item1 B<Resources>
    =item2 L<The Raku Guide|https://raku.guide/>
    =item2 L<Books |https://perl6book.com/>
    =item2 L<Rosetta Code | https://www.raku.org/community/rosettacode>

=end nested
=begin nested :!nested

=item1 B<Resoures>
    =item2 L<Download | file:../download/index.podlite>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>

=item1 B<Learning>
    =item2 L<The Raku Guide|https://raku.guide/>
    =item2 L<Wikibook |https://en.wikibooks.org/wiki/Raku_Programming>
    =item2 L<Books |https://perl6book.com/>
    =item2 L<Rosetta Code | https://www.raku.org/community/rosettacode>
    =item2 L<Learn Raku in Y minutes|https://learnxinyminutes.com/docs/raku/>
    =item2 L<Golfing |https://github.com/AlexDaniel/raku-golf-cheatsheet>
=end nested
=begin nested :!nested

=item1 B<Explore>
    =item2 L<Raku Blog Aggregator|https://planet.raku.org/>
    =item2 L<Rakudo Weekly|https://rakudoweekly.blog/>
    =item2 L<The Weekly Challenge |https://perlweeklychallenge.org/>
    =item2 L<Raku Advent Calendar|https://raku-advent.blog/>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>
    =item2 L<empty|#>

=end nested
=end React


=begin React :component<CookieConsent> :id<CookieConsent> :buttonCaption("Got it!")
=para
This website uses cookies for analytics.
=end React


README

NAME

SYNOPSIS

DESCRIPTION

AUTHOR

COPYRIGHT AND LICENSE

Slang::Piersing v0.0.2

Authors

License

Dependencies

Test Dependencies

Provides

Documentation