/ 
Hustle-Table-v0.8.0
River stage zero No dependents
/ Hustle::Table

NAME

Hustle::Table - Cached general purpose dispatch and routing table

SYNOPSIS

use Hustle::Table;

Create a new table:

my $table=Hustle::Table->new;

Add entry as hash ref:

$table->add( { matcher => "regex (match)", value=> "a value"});

Add entry as array ref (3 elements required):

$table->add( ["another", "another value", undef])

Add entry as flat key value pairs:

$table->add(matcher=>"jones", value=> sub {"one more"}, type=>"begin");

Add entry as tuple

$table->add("magic matcher" => "to a value");

Set the default entry:

$table->set_default("default value");

Prepare a dispatcher external cache:

my %cache;
my $dispatch = $table->prepare_dispatcher(cache=>\%cache);

Call dispatcher to return the matching entries and any RegExp captures. Multiple items can be tested in a single call

my @pairs=$dispatch->("thing to match", "another thing", ...);	

# @pairs contains pairs of entries and capture arrays

# perl v5.36 
for my($e, $c)(@pairs){
  $e->[1]; # The value 
  $c;      # Possible captures
}

DESCRIPTION

This module provides a class to construct a routing table and build a high performance dispatcher from it.

A table can have any combination of RegExp, subroutine, exact string, begin string, end string or numeric matching of entries. The order in which the entries are added defines their precedence. First in, first tested.

In the case of no entries matching the input, a default/fallback entry always matches.

Once all the entries have been added to the table, a dispatcher needs to be prepared/created. The dispatcher is an anonymous subroutine, which tests its arguments against the matcher in each entry in the table.

NOTE: From v0.7.0 The entries that matched the input are returned along with an anonymous array of RegExp captures if applicable, as a pair. Multiple pairs are returned if more than one match. Prior to v0.7.0, testing would stop after the first match.

If more entries are required to be added to the table, the dispatcher must be prepared again.

A cache (hash) is used to drastically improve table lookup performance. Entries are automatically added to the cache. Removal of cache entries is up to the user to implement on a application basis.

API Change

From v0.8.0: Matchers MUST be input as strings or CODE refs only. Regexp matchers are generated internally from the matcher string. This is aid searching through the table, for modifications by other packages. CODE matchers MUST specify the optional type argument as "code";

From v0.6.0: Regexp from non core Regexp engines are now usable as a matcher directly. In previous versions, these where not detected and processed as a string to be converted into a Perl core Regexp internally.

In version v0.5.3 and earlier, the dispatcher would always return a two element list. The first being the match entry, and the second array ref of any captures from a RegExp match. If the matcher type was 'begin', 'end', 'exact', or 'numeric', the second element would always be an reference to an empty array.

From v0.5.4 onwards to optimise performance of non RegExp matching, this is no longer the case. Only RegExp type matching will generate this second element. Other matching types will not.

In other words when calling the dispatcher:

my ($entry, $captures)=$dispatcher->($input)

The $captures variable above now will be undef instead of [], for non RegExp matching

CREATING A TABLE

Hustle::Table->new(...);

Calling the class constructor returns a new table. There are no required arguments:

my $table=Hustle::Table->new;

In this case, a default catch all entry (an undef value) is added automatically.

If an argument is provided, it is the value used in the default/catch all entry:

my $table=Hustle::Table->new($default);

ENTRIES

Structure

An entry is an anonymous array containing the following elements:

[matcher, value, type]
matcher

matcher can be a RegExp (as source string), a subroutine, a string or a numeric value.

When matcher treated as a RegExp, any captures are returned as the second item of the pair when calling the dispatcher

When matcher is a subroutine, it is called with input to test and a reference to the value field in the entry as the two arguments. If it returns a true value it matches.

When matcher is string or numeric value, the last field type specifies how to perform the match. See type below.

If no type is specified or is undef, the matcher is always treated as a RegExp. From v0.8.0: If treated as a RegExp, the type field is replaced with the compiled RexExp.

value

This is the data you want to retrieve from the table when entry matches the input.

type

type is used to adjust how the matcher is interpreted. The possible values are:

undef	  => 	matcher treated as a RegExp source stirng. 

"code"  =>  uses code refernce to match argument

"begin"	=>	matcher string matches the begining of input string 

"end"	  =>  matcher string matches the end of input string 

"exact"	=>	matcher string matches string equality 

"numeric" =>	matcher number matches numeric equality

Adding

$table->add(...);

Entries are added in anonymous hash, anonymous array or flattened format, using the add method.

Anonymous array entries must contain 3 elements, in the order of:

$table->add([$matcher, $value, $type]);

Anonymous hashes format only need to specify the matcher and value pairs:

$table->add({matcher=>$matcher, value=>$value, type=>$type});

Single flattened format takes a list directly. It must contain 4 elements, and will be treated as a RegExp match:

$table->add(matcher=>$matcher, value=> $value);

Single simple format takes two elements and will be treated as RegExp match:

$table->add("some matcher"=>$value);

Or add multiple at once using mixed formats together

$table->add( [$matcher, $value, $type], {matcher=> $matcher, value=>$value},
matcher=>$matcher, value=>$value);

In any case,matcher and value are the only items which must be defined for subroutine and RegExp matchers. String, numeric and code matching will need the type also specified.

Default Matcher

$table->set_default($value)

Each list has a default matcher that will unconditionally match the input. It is always in the table and is only tested when no other matcher matched

If the default matcher matches it will return $value on matching and an empty capture array.

Manipulating Table Entries

There are no explicit manipulation methods. The table is just an array and it can be accessed like an any other array e.g. accessing elements, splice, shift, unshift, pop, push.

Just keep in mind the last item in the table is always the default matcher.

After entires have been modified the dispatcher must be prepared again

PREPARING A DISPATCHER

my $dispatcher=$table->prepare_dispatcher(%args);

Once all the entries are added to the table, the dispatcher can be constructed by calling prepare_dispatcher:

Arguments to this method include:

cache

The hash ref to use as the dispatchers cache. Specifying a hash allows external management. If no cache is specified an internal cache is used.

When a dispatcher is prepared, the cache is emptied, any RegExp matchers are compiled and the table is forced to always have at least one entry (the default matcher).

USING A DISPATCHER

my @pairs=$dispatcher->("input");

# perl v5.36 
for my($e, $c)(@pairs){
  $e->[1]; # The value 
  $c;      # Possible captures
}

The dispatcher is simply a sub, which you call with the input to match against the table entries:

The returned list are pairs of entries and captures

The first pair item is the array reference to the table entry that matched (or the default entry if no match was found). The value associated with the table entry is located in position 1

The second pair item is an anonymous array of any captures due to a matching RegExp, or undef otherwise

NOTE In version 0.5.3 and earlier: the second element was returned as a ref to an empty array even if the matcher was not a RegExp.

COMPARISON TO OTHER MODULES

Solid performance compared to other Perl routing/dispatch modules. Faster in basic tests then other Perl modules:

Smart::Dispatch Router::Simple Router::Boom

If you need even more performance then checkout URI::Router

TODO: make proper benchmark and comparison

AUTHOR

Ruben Westerberg, <drclaw@mac.com>

REPOSITORTY and BUGS

Please report any bugs via git hub: http://github.com/drclaw1394/perl5-hustle-table

COPYRIGHT AND LICENSE

Copyright (C) 2025 by Ruben Westerberg

Licensed under MIT

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.