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=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>
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use v6.d;

module Hash::LRU:ver<0.0.5>:auth<zef:lizmat> {

    # The basic logic for keeping LRU data up-to-date
    my role basic {
        method AT-KEY(::?CLASS:D: \key) is raw is hidden-from-backtrace {
            self!SEEN-KEY(key) if self.EXISTS-KEY(key);
            nextsame
        }
        method ASSIGN-KEY(::?CLASS:D: \key, \value) is hidden-from-backtrace {
            self!SEEN-KEY(key);
            nextsame
        }
        method BIND-KEY(::?CLASS:D: \key, \value) is hidden-from-backtrace {
            self!SEEN-KEY(key);
            nextsame
        }
        method STORE(\to_store) is hidden-from-backtrace {
            callsame;
            self!INIT-KEYS;
            self!SEEN-KEY($_) for self.keys;
            self
        }
    }

    # The role to be applied when a specific limit is given for hashes
    my role limit-given-hash[$max] does basic {
        my int $max-elems = $max;  # cannot parameterize to a native int yet
        has str @!keys;

        method !INIT-KEYS(--> Nil) {
            @!keys = ();
        }

        method !SEEN-KEY(Str(Any) $key --> Nil) {
            if @!keys.elems -> int $elems {
                my int $i = -1;
                Nil while ++$i < $elems && @!keys.AT-POS($i) ne $key;
                if $i < $elems {
                    @!keys.splice($i,1);
                }
                elsif $elems == $max-elems {
                    self.DELETE-KEY(@!keys.pop);
                }
            }
            @!keys.unshift($key);
        }
    }

    # The role to be applied when a specific limit is given for object hashes
    my role limit-given-object-hash[$max] does basic {
        my int $max-elems = $max;  # cannot parameterize to a native int yet
        has str @!whiches;
        has @!keys;

        method !INIT-KEYS(--> Nil) {
            @!whiches = ();
            @!keys    = ();
        }

        method !SEEN-KEY(\key --> Nil) {
            my str $WHICH = key.WHICH;
            if @!whiches.elems -> int $elems {
                my int $i = -1;
                Nil while ++$i < $elems && @!whiches.AT-POS($i) ne $WHICH;
                if $i < $elems {
                    @!whiches.splice($i,1);
                    @!keys.splice($i,1);
                }
                elsif $elems == $max-elems {
                    @!whiches.pop;
                    self.DELETE-KEY(@!keys.pop);
                }
            }
            @!whiches.unshift($WHICH);
            @!keys.unshift(key);
        }
    }

    # Handle the "is LRU" / is LRU(Bool:D) cases
    multi sub trait_mod:<is>(Variable:D \v, Bool:D :$LRU!) is export {
        die "Can only apply 'is LRU' on a Hash, not a {v.var.WHAT}"
          unless v.var.WHAT ~~ Hash;
        my $name = v.var.^name;
        if $LRU {
            trait_mod:<does>(v, v.var.keyof =:= Str(Any)
              ?? limit-given-hash[100]
              !! limit-given-object-hash[100]
            );
            v.var.WHAT.^set_name("$name\(LRU)");
        }
    }

    # Handle the "is LRU(elements => N)" case
    multi sub trait_mod:<is>(Variable:D \v, :%LRU!) is export {
        die "Can only apply 'is LRU' on a Hash, not a {v.var.WHAT}"
          unless v.var.WHAT ~~ Hash;
        my $name = v.var.^name;

        if %LRU<elements>:exists {
            with %LRU<elements> {
                trait_mod:<does>(v, v.var.keyof =:= Str(Any)
                  ?? limit-given-hash[$_]
                  !! limit-given-object-hash[$_]
                );
            }
            else {
                die "Cannot use an undefined value for 'elements' in 'is LRU'. "
                    ~ 'Did you try to set it at runtime?';
            }
        }
        elsif %LRU.keys.sort -> @keys {
            die "Don't know what to do with '{ @keys }' in 'is LRU'";
        }
        v.var.WHAT.^set_name("$name\(LRU)");
    }
}



Hash::LRU - trait for limiting number of keys in hashes by usage


my %h is LRU;   # defaults to elements => 100


my %h is LRU(elements => 42);  # note: value must be known at compile time!


my %h{Any} is LRU;  # object hashes also supported


Hash::LRU provides a C<is LRU> trait on C<Hash>es as an easy way to limit
the number of keys kept in the C<Hash>.  Keys will be added as long as
the number of keys is under the limit.  As soon as a new key is added that
would exceed the limit, the least recently used key is removed from the
C<Hash>.


Both "normal" as well as object hashes are supported.


%h<name>       = "Alex";
%h<language>   = "Raku";
%h<occupation> = "devops";
%h<location>   = "Russia";


say %h.raku;
# {:location("Russia"), :occupation("devops"), :language("Raku")}


Source can be located at: https://github.com/lizmat/Hash-LRU . 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.


# Need to be using NQP ops here to get the desired efficiency, and
# hopefully this will be integrated into Rakudo before soon.
use nqp;

class Hash::int:ver<0.0.3>:auth<zef:lizmat> {
    has $!hash handles <gist raku Str values pairs iterator>;

    method new() {
        nqp::p6bindattrinvres(nqp::create(self),self,'$!hash',nqp::hash)
    }

    method STORE(::?CLASS:D: \to-store, :$INITIALIZE) {
        my $iterator := to-store.iterator;
        my $hash     := $INITIALIZE ?? $!hash !! ($!hash := nqp::hash);
        my Mu $x;
        my Mu $y;

        nqp::until(
          nqp::eqaddr(($x := $iterator.pull-one),IterationEnd),
          nqp::if(
            nqp::istype($x,Pair),
            nqp::bindkey(
              $hash,
              (my int $ = nqp::getattr(nqp::decont($x),Pair,'$!key').Int),
              (nqp::getattr(nqp::decont($x),Pair,'$!value'))
            ),
            nqp::if(
              (nqp::istype($x,Map) && nqp::not_i(nqp::iscont($x))),
              self.STORE($x),
              nqp::if(
                nqp::eqaddr(($y := $iterator.pull-one),IterationEnd),
                nqp::if(
                  nqp::istype($x,Failure),
                  $x.throw,
                  X::Hash::Store::OddNumber.new(
                    found => nqp::add_i(nqp::mul_i(nqp::elems($hash),2),1),
                    last  => $x
                  ).throw
                ),
                nqp::bindkey($hash,(my int $ = $x.Int),$y)
              )
            )
          )
        );
        self
    }

    method AT-KEY(::?CLASS:D: int $key) is raw {
        nqp::atkey($!hash,$key)
    }
    method ASSIGN-KEY(::?CLASS:D: int $key, \value) is raw {
        nqp::bindkey($!hash,$key,value)
    }
    method BIND-KEY(::?CLASS:D: int $key, \value) is raw {
        nqp::bindkey($!hash,$key,value)
    }
    method DELETE-KEY(::?CLASS:D: int $key) is raw {
        my $value := nqp::atkey($!hash,$key);
        nqp::deletekey($!hash,$key);
        $value
    }
    method EXISTS-KEY(::?CLASS:D: int $key) is raw {
        nqp::hllbool(nqp::existskey($!hash,$key))
    }
    method keys(::?CLASS:D:) {
        nqp::hllize($!hash).keys.map: *.Int
    }
    method kv(::?CLASS:D:) {
        nqp::hllize($!hash).map: { (.key.Int, .value).Slip }
    }
}



Hash::int - provide a hash with native integer keys


=begin code :lang<raku>

use Hash::int;

my %hash is Hash::int = 42 => "foo", 666 => "bar";

=end code


Hash::int is module that provides the C<Hash::int> class to be applied
to the initialization of an Associative, making it limit the keys to
native integers that fit the C<int> type.  This allows this module to
take some shortcuts, making it up to 7x as fast as a normal hash.


Source can be located at: https://github.com/lizmat/Hash-int . 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.


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|#>
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=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


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README

NAME

SYNOPSIS

DESCRIPTION

AUTHOR

COPYRIGHT AND LICENSE

Hash::int v0.0.3

Authors

License

Dependencies

Test Dependencies

Provides

Documentation