man > Eval::TypeTiny(3pm)

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 "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.

    "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>.

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

AUTHOR
    Toby Inkster <tobyink AT cpan.org>.

COPYRIGHT AND LICENCE
    This software is copyright (c) 2013-2014, 2017-2023 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.