perldoc > Eval::TypeTiny

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🏷️ NAME

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

🚀 Quick Reference

Use Case	Command	Description
Compile a closure from a code string	eval_closure(source => 'sub { ... }', environment => \%env)	Compiles a coderef from a Perl code string, with optional closed-over variables
Check alias implementation	use Eval::TypeTiny qw(ALIAS_IMPLEMENTATION);	Returns a string indicating which alias implementation is active
Check lexical sub support	use Eval::TypeTiny qw(HAS_LEXICAL_SUBS);	Boolean indicating if lexical subs are supported (requires Perl 5.18+)
Use feature pragma inside eval	eval_closure(source => 'sub { use feature qw(say); say for @_ }')	Import pragmas inside the evaluated string to enable features

📊 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

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

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

🔢 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 IMPLEMENTAION_* 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.

🔧 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>.

📚 SEE ALSO

Eval::Closure, Error::TypeTiny::Compilation.

👤 AUTHOR

Toby Inkster <tobyink AT cpan.org>.

©️ COPYRIGHT AND LICENCE

This software is copyright (c) 2013-2014, 2017-2021 by Toby Inkster.

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.

🏷️ NAME 🚀 Quick Reference 📊 STATUS 📖 DESCRIPTION 🔧 EVALUATION ENVIRONMENT 🐛 BUGS 📚 SEE ALSO 👤 AUTHOR ©️ COPYRIGHT AND LICENCE ⚠️ DISCLAIMER OF WARRANTIES