1Eval::TypeTiny(3)     User Contributed Perl Documentation    Eval::TypeTiny(3)
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NAME

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

10       This module is covered by the Type-Tiny stability policy.
11

DESCRIPTION

13       This module is used by Type::Tiny to compile coderefs from strings of
14       Perl code, and hashrefs of variables to close over.
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16   Functions
17       By default this module exports one function, which works much like the
18       similarly named function from Eval::Closure:
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20       "eval_closure(source => $source, environment => \%env, %opt)"
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22       Other functions can be imported on request:
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24       "set_subname( $fully_qualified_name, $coderef )"
25           Works like the similarly named function from Sub::Util, but will
26           fallback to doing nothing if neither Sub::Util nor Sub::Name are
27           available. Also will cowardly refuse the set the name of a coderef
28           a second time if it's already named it.
29
30       "type_to_coderef( $type, %options )"
31           Turns a Type::Tiny object into a coderef, suitable for installing
32           into a symbol table to create a function like "ArrayRef" or "Int".
33           (Actually should work for any object which provides
34           "is_parameterizable", "parameterize", and "qualified_name" methods,
35           such as Type::Coercion.)
36
37           $options{post_method} can be a string of Perl indicating a method
38           to call on the type constraint before returning it. For example
39           '->moose_type'.
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41           $options{description} can be a description of the coderef which may
42           be shown in stack traces, etc.
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44           The coderef will be named using "set_subname" unless
45           $options{anonymous} is true.
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47           If $type is undef, then it is assumed that the type constraint
48           hasn't been defined yet but will later, yet you still want a
49           function now.  $options{type_library} and $options{type_name} will
50           be used to find the type constraint when the function gets called.
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52   Constants
53       The following constants may be exported, but are not by default.
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55       "HAS_LEXICAL_SUBS"
56           Boolean indicating whether Eval::TypeTiny has support for lexical
57           subs.  (This feature requires Perl 5.18.)
58
59       "ALIAS_IMPLEMENTATION"
60           Returns a string indicating what implementation of "alias => 1" is
61           being used. Eval::TypeTiny will automatically choose the best
62           implementation.  This constant can be matched against the
63           "IMPLEMENTAION_*" constants.
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65       "IMPLEMENTATION_NATIVE"
66           If "ALIAS_IMPLEMENTATION eq IMPLEMENTATION_NATIVE" then
67           Eval::TypeTiny is currently using Perl 5.22's native alias feature.
68           This requires Perl 5.22.
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70       "IMPLEMENTATION_DEVEL_LEXALIAS"
71           If "ALIAS_IMPLEMENTATION eq IMPLEMENTATION_DEVEL_LEXALIAS" then
72           Eval::TypeTiny is currently using Devel::LexAlias to provide
73           aliases.
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75       "IMPLEMENTATION_PADWALKER"
76           If "ALIAS_IMPLEMENTATION eq IMPLEMENTATION_PADWALKER" then
77           Eval::TypeTiny is currently using PadWalker to provide aliases.
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79       "IMPLEMENTATION_TIE"
80           If "ALIAS_IMPLEMENTATION eq IMPLEMENTATION_TIE" then Eval::TypeTiny
81           is using the fallback implementation of aliases using "tie". This
82           is the slowest implementation, and may cause problems in certain
83           edge cases, like trying to alias already-tied variables, but it's
84           the only way to implement "alias => 1" without a recent version of
85           Perl or one of the two optional modules mentioned above.
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87       "NICE_PROTOTYPES"
88           If this is true, then type_to_coderef will give parameterizable
89           type constraints the slightly nicer prototype of "(;$)" instead of
90           the default "(;@)". This allows constructs like:
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92              ArrayRef[Int] | HashRef[Int]
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94           ... to "just work".
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EVALUATION ENVIRONMENT

97       The evaluation is performed in the presence of strict, but the absence
98       of warnings. (This is different to Eval::Closure which enables warnings
99       for compiled closures.)
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101       The feature pragma is not active in the evaluation environment, so the
102       following will not work:
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104          use feature qw(say);
105          use Eval::TypeTiny qw(eval_closure);
106
107          my $say_all = eval_closure(
108             source => 'sub { say for @_ }',
109          );
110          $say_all->("Hello", "World");
111
112       The feature pragma does not "carry over" into the stringy eval. It is
113       of course possible to import pragmas into the evaluated string as part
114       of the string itself:
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116          use Eval::TypeTiny qw(eval_closure);
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118          my $say_all = eval_closure(
119             source => 'sub { use feature qw(say); say for @_ }',
120          );
121          $say_all->("Hello", "World");
122

BUGS

124       Please report any bugs to
125       <https://github.com/tobyink/p5-type-tiny/issues>.
126

SEE ALSO

128       Eval::Closure, Error::TypeTiny::Compilation.
129

AUTHOR

131       Toby Inkster <tobyink@cpan.org>.
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134       This software is copyright (c) 2013-2014, 2017-2023 by Toby Inkster.
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136       This is free software; you can redistribute it and/or modify it under
137       the same terms as the Perl 5 programming language system itself.
138

DISCLAIMER OF WARRANTIES

140       THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
141       WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
142       MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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146perl v5.38.0                      2023-07-21                 Eval::TypeTiny(3)
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