perlancar > Perinci-Sub-Util-0.45 > Perinci::Sub::Util



Annotate this POD



Open  0
View/Report Bugs
Module Version: 0.45   Source  


Perinci::Sub::Util - Helper when writing functions


This document describes version 0.45 of Perinci::Sub::Util (from Perl distribution Perinci-Sub-Util), released on 2016-02-21.


Example for err() and caller():

 use Perinci::Sub::Util qw(err caller);

 sub foo {
     my %args = @_;
     my $res;

     my $caller = caller();

     $res = bar(...);
     return err($err, 500, "Can't foo") if $res->[0] != 200;

     [200, "OK"];

Example for die_err() and warn_err():

 use Perinci::Sub::Util qw(warn_err die_err);
 warn_err(403, "Forbidden");
 die_err(403, "Forbidden");

Example for gen_modified_sub():

 use Perinci::Sub::Util qw(gen_modified_sub);

 $SPEC{list_users} = {
     v => 1.1,
     args => {
         search => {},
         is_suspended => {},
 sub list_users { ... }

     output_name => 'list_suspended_users',
     base_name   => 'list_users',
     remove_args => ['is_suspended'],
     output_code => sub {
         list_users(@_, is_suspended=>1);

Example for gen_curried_sub():

 use Perinci::Sub::Util qw(gen_curried_sub);

 $SPEC{list_users} = {
     v => 1.1,
     args => {
         search => {},
         is_suspended => {},
 sub list_users { ... }

 # simpler/shorter than gen_modified_sub, but can be used for currying only
 gen_curried_sub('list_users', {is_suspended=>1}, 'list_suspended_users');


gen_curried_sub($base_name, $output_name, $set_args) -> any

Generate curried subroutine (and its metadata).

This is a more convenient helper than gen_modified_sub if you want to create a new subroutine that has some of its arguments preset (so they no longer need to be present in the new metadata).

For more general needs of modifying a subroutine (e.g. add some arguments, modify some arguments, etc) use gen_modified_sub.

This function is not exported by default, but exportable.

Arguments ('*' denotes required arguments):

Return value: (any)

gen_modified_sub(%args) -> [status, msg, result, meta]

Generate modified metadata (and subroutine) based on another.

Often you'll want to create another sub (and its metadata) based on another, but with some modifications, e.g. add/remove/rename some arguments, change summary, add/remove some properties, and so on.

Instead of cloning the Rinci metadata and modify it manually yourself, this routine provides some shortcuts.

You can specify base sub/metadata using base_name (string, subroutine name, either qualified or not) or base_code (coderef) + base_meta (hash).

This function is not exported by default, but exportable.

Arguments ('*' denotes required arguments):

Returns an enveloped result (an array).

First element (status) is an integer containing HTTP status code (200 means OK, 4xx caller error, 5xx function error). Second element (msg) is a string containing error message, or 'OK' if status is 200. Third element (result) is optional, the actual result. Fourth element (meta) is called result metadata and is optional, a hash that contains extra information.

Return value: (hash)

caller([ $n ])

Just like Perl's builtin caller(), except that this one will ignore wrapper code in the call stack. You should use this if your code is potentially wrapped. See Perinci::Sub::Wrapper for more details.

err(...) => ARRAY


Generate an enveloped error response (see Rinci::function). Can accept arguments in an unordered fashion, by utilizing the fact that status codes are always integers, messages are strings, result metadata are hashes, and previous error responses are arrays. Error responses also seldom contain actual result. Status code defaults to 500, status message will default to "FUNC failed". This function will also fill the information in the logs result metadata.


 err();    # => [500, "FUNC failed", undef, {...}];
 err(404); # => [404, "FUNC failed", undef, {...}];
 err(404, "Not found"); # => [404, "Not found", ...]
 err("Not found", 404); # => [404, "Not found", ...]; # order doesn't matter
 err([404, "Prev error"]); # => [500, "FUNC failed", undef,
                           #     {logs=>[...], prev=>[404, "Prev error"]}]

Will put stack_trace in logs only if Carp::Always module is loaded.


This is a shortcut for:

 $res = err(...);
 warn "ERROR $res->[0]: $res->[1]";


This is a shortcut for:

 $res = err(...);
 die "ERROR $res->[0]: $res->[1]";


What if I want to put result ($res->[2]) into my result with err()?

You can do something like this:

 my $err = err(...) if ERROR_CONDITION;
 $err->[2] = SOME_RESULT;
 return $err;


Please visit the project's homepage at


Source repository is at


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.




perlancar <>


This software is copyright (c) 2016 by

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

syntax highlighting: