NAME

Venus::Constraint - Constraint Class

ABSTRACT

Constraint Class for Perl 5

SYNOPSIS

  package main;

  use Venus::Constraint;

  my $constraint = Venus::Constraint->new;

  # $constraint->accept('float');

  # $constraint->ensure(sub{$_ > 1});

  # $constraint->result(1.01);

  # true

DESCRIPTION

This package provides a mechanism for evaluating type constraints on data. Built-in type constraints are handled via Venus::Check.

INHERITS

This package inherits behaviors from:

Venus::Kind::Utility

INTEGRATES

This package integrates behaviors from:

Venus::Role::Buildable

METHODS

This package provides the following methods:

accept

  accept(string $name, any @args) (Venus::Constraint)

The accept method registers a condition via "check" based on the arguments provided. The built-in types are defined as methods in Venus::Check.

Since 3.55

accept example 1

  # given: synopsis

  package main;

  $constraint = $constraint->accept('float');

  # bless(..., "Venus::Constraint")

  # $constraint->result;

  # false

  # $constraint->result(1.01);

  # true

accept example 2

  # given: synopsis

  package main;

  $constraint = $constraint->accept('number');

  # bless(..., "Venus::Constraint")

  # $constraint->result(1.01);

  # false

  # $constraint->result(1_01);

  # true

accept example 3

  # given: synopsis

  package Example1;

  sub new {
    bless {};
  }

  package Example2;

  sub new {
    bless {};
  }

  package main;

  $constraint = $constraint->accept('object');

  # bless(..., "Venus::Constraint")

  # $constraint->result;

  # false

  # $constraint->result(qr//);

  # false

  # $constraint->result(Example1->new);

  # true

  # $constraint->result(Example2->new);

  # true

accept example 4

  # given: synopsis

  package Example1;

  sub new {
    bless {};
  }

  package Example2;

  sub new {
    bless {};
  }

  package main;

  $constraint = $constraint->accept('Example1');

  # bless(..., "Venus::Constraint")

  # $constraint->result;

  # false

  # $constraint->result(qr//);

  # false

  # $constraint->result(Example1->new);

  # true

  # $constraint->result(Example2->new);

  # false

check

  check(Venus::Check $data) (Venus::Check)

The check method gets or sets the Venus::Check object used for performing runtime data type validation.

Since 3.55

check example 1

  # given: synopsis

  package main;

  my $check = $constraint->check(Venus::Check->new);

  # bless(..., 'Venus::Check')

check example 2

  # given: synopsis

  package main;

  $constraint->check(Venus::Check->new);

  my $check = $constraint->check;

  # bless(..., 'Venus::Check')

clear

  clear() (Venus::Constraint)

The clear method resets the "check" attributes and returns the invocant.

Since 3.55

clear example 1

  # given: synopsis

  package main;

  $constraint->accept('string');

  $constraint = $constraint->clear;

  # bless(..., "Venus::Constraint")

ensure

  ensure(coderef $code) (Venus::Constraint)

The ensure method registers a custom (not built-in) constraint condition and returns the invocant.

Since 3.55

ensure example 1

  # given: synopsis

  package main;

  $constraint->accept('number');

  my $ensure = $constraint->ensure(sub {
    $_ >= 0
  });

  # bless(.., "Venus::Constraint")

ensure example 2

  # given: synopsis

  package main;

  $constraint->accept('number');

  my $ensure = $constraint->ensure(sub {
    my ($source, $value) = @_;

    if ($value >= 0) {
      return 1;
    }
    else {
      return 0;
    }
  });

  # bless(..., "Venus::Constraint")

eval

  eval(any $data) (boolean)

The eval method dispatches to the "check" object as well as evaluating any custom conditions, and returns true if all conditions pass, and false if any condition fails.

Since 3.55

eval example 1

  # given: synopsis

  package main;

  $constraint->accept('float');

  $constraint->ensure(sub{$_ >= 1});

  my $eval = $constraint->eval('1.00');

  # true

eval example 2

  # given: synopsis

  package main;

  $constraint->accept('float');

  $constraint->ensure(sub{$_ >= 1});

  my $eval = $constraint->eval('0.99');

  # false

evaler

  evaler(any @args) (coderef)

The evaler method returns a coderef which calls the "eval" method with the invocant when called.

Since 3.55

evaler example 1

  # given: synopsis

  package main;

  my $evaler = $constraint->evaler;

  # sub{...}

  # my $result = $evaler->();

  # false

evaler example 2

  # given: synopsis

  package main;

  my $evaler = $constraint->accept('any')->evaler;

  # sub{...}

  # my $result = $evaler->();

  # true

result

  result(any $data) (boolean)

The result method dispatches to the "eval" method and returns the result.

Since 3.55

result example 1

  # given: synopsis

  package main;

  $constraint->accept('float');

  $constraint->ensure(sub{$_ >= 1});

  my $result = $constraint->result('1.00');

  # true

result example 2

  # given: synopsis

  package main;

  $constraint->accept('float');

  $constraint->ensure(sub{$_ >= 1});

  my $result = $constraint->result('0.99');

  # false

AUTHORS

Awncorp, awncorp@cpan.org

LICENSE

Copyright (C) 2022, Awncorp, awncorp@cpan.org.

This program is free software, you can redistribute it and/or modify it under the terms of the Apache license version 2.0.

cpanm Venus

perl -MCPAN -e shell
install Venus