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@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.

perl v5.36.0                                       2023-07-21                                Eval::TypeTiny(3pm)