Eval::TypeTiny

(source, CPAN)

version 2.006000

NAME
STATUS
DESCRIPTION
- Functions
- Constants
EVALUATION ENVIRONMENT
BUGS
SEE ALSO
AUTHOR
COPYRIGHT AND LICENCE
DISCLAIMER OF WARRANTIES

#NAME

Eval::TypeTiny - utility to evaluate a string of Perl code in a clean environment

#STATUS

This module is covered by the Type-Tiny stability policy.

#DESCRIPTION

This module is used by Type::Tiny to compile coderefs from strings of Perl code, and hashrefs of variables to close over.

#Functions

By default this module exports one function, which works much like the similarly named function from Eval::Closure:

#eval_closure(source => $source, environment => \%env, %opt)

Other functions can be imported on request:

#set_subname( $fully_qualified_name, $coderef )

Works like the similarly named function from Sub::Util, but will fallback to doing nothing if neither Sub::Util nor Sub::Name are available. Also will cowardly refuse the set the name of a coderef a second time if it's already named it.

#type_to_coderef( $type, %options )

Turns a Type::Tiny object into a coderef, suitable for installing into a symbol table to create a function like ArrayRef or Int. (Actually should work for any object which provides is_parameterizable, parameterize, and qualified_name methods, such as Type::Coercion.)

$options{post_method} can be a string of Perl indicating a method to call on the type constraint before returning it. For example '->moose_type'.

$options{description} can be a description of the coderef which may be shown in stack traces, etc.

The coderef will be named using set_subname unless $options{anonymous} is true.

If $type is undef, then it is assumed that the type constraint hasn't been defined yet but will later, yet you still want a function now. $options{type_library} and $options{type_name} will be used to find the type constraint when the function gets called.

#Constants

The following constants may be exported, but are not by default.

#HAS_LEXICAL_SUBS

Boolean indicating whether Eval::TypeTiny has support for lexical subs. (This feature requires Perl 5.18.)

#ALIAS_IMPLEMENTATION

Returns a string indicating what implementation of alias => 1 is being used. Eval::TypeTiny will automatically choose the best implementation. This constant can be matched against the IMPLEMENTATION_* constants.

#IMPLEMENTATION_NATIVE

If ALIAS_IMPLEMENTATION eq IMPLEMENTATION_NATIVE then Eval::TypeTiny is currently using Perl 5.22's native alias feature. This requires Perl 5.22.

#IMPLEMENTATION_DEVEL_LEXALIAS

If ALIAS_IMPLEMENTATION eq IMPLEMENTATION_DEVEL_LEXALIAS then Eval::TypeTiny is currently using Devel::LexAlias to provide aliases.

#IMPLEMENTATION_PADWALKER

If ALIAS_IMPLEMENTATION eq IMPLEMENTATION_PADWALKER then Eval::TypeTiny is currently using PadWalker to provide aliases.

#IMPLEMENTATION_TIE

If ALIAS_IMPLEMENTATION eq IMPLEMENTATION_TIE then Eval::TypeTiny is using the fallback implementation of aliases using tie. This is the slowest implementation, and may cause problems in certain edge cases, like trying to alias already-tied variables, but it's the only way to implement alias => 1 without a recent version of Perl or one of the two optional modules mentioned above.

#NICE_PROTOTYPES

If this is true, then type_to_coderef will give parameterizable type constraints the slightly nicer prototype of (;$) instead of the default (;@). This allows constructs like:

ArrayRef[Int] | HashRef[Int]

... to "just work".

#EVALUATION ENVIRONMENT

The evaluation is performed in the presence of strict, but the absence of warnings. (This is different to Eval::Closure which enables warnings for compiled closures.)

The feature pragma is not active in the evaluation environment, so the following will not work:

use feature qw(say);
use Eval::TypeTiny qw(eval_closure);

my $say_all = eval_closure(
   source => 'sub { say for @_ }',
);
$say_all->("Hello", "World");

The feature pragma does not "carry over" into the stringy eval. It is of course possible to import pragmas into the evaluated string as part of the string itself:

use Eval::TypeTiny qw(eval_closure);

my $say_all = eval_closure(
   source => 'sub { use feature qw(say); say for @_ }',
);
$say_all->("Hello", "World");

#BUGS

Please report any bugs to https://github.com/tobyink/p5-type-tiny/issues.

#AUTHOR

Toby Inkster <tobyink@cpan.org>.

#COPYRIGHT AND LICENCE

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

#DISCLAIMER OF WARRANTIES

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

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