NAME

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

VERSION

This document describes version 0.471 of Perinci::Sub::Util (from Perl distribution Perinci-Sub-Util), released on 2023-07-02.

SYNOPSIS

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 { ... }

gen_modified_sub(
    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');

FUNCTIONS

gen_curried_sub

Usage:

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

$base_name* => str

Subroutine name (either qualified or not).

If not qualified with package name, will be searched in the caller's package. Rinci metadata will be searched in %SPEC package variable.
$output_name => str

Where to install the modified sub.

Subroutine will be put in the specified name. If the name is not qualified with package name, will use caller's package. If the name is not specified, will use the base name which must not be in the caller's package.
$set_args* => hash

Arguments to set.

Return value: (any)

gen_modified_sub

Usage:

gen_modified_sub(%args) -> [$status_code, $reason, $payload, \%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):

add_args => hash

Arguments to add.
base_code => code

Base subroutine code.

If you specify this, you'll also need to specify base_meta.

Alternatively, you can specify base_name instead, to let this routine search the base subroutine from existing Perl package.
base_meta => hash

Base Rinci metadata.
base_name => str

Subroutine name (either qualified or not).

If not qualified with package name, will be searched in the caller's package. Rinci metadata will be searched in %SPEC package variable.

Alternatively, you can also specify base_code and base_meta.

Either base_name or base_code + base_meta are required.
description => str

Description for the mod subroutine.
install_sub => bool (default: 1)

(No description)
modify_args => hash

Arguments to modify.

For each argument you can specify a coderef. The coderef will receive the argument ($arg_spec) and is expected to modify the argument specification.
modify_meta => code

Specify code to modify metadata.

Code will be called with arguments ($meta) where $meta is the cloned Rinci metadata.
output_code => code

Code for the modified sub.

Alternatively you can use wrap_code. If both are not specified, will use base_code (which will then be required) as the modified subroutine's code.
output_name => str

Where to install the modified sub.

Output subroutine will be put in the specified name. If the name is not qualified with package name, will use caller's package. If the name is not specified, the base name will be used and must not be from the caller's package.

Note that this argument is optional.

To prevent installing subroutine, set install_sub to false.
remove_args => array

List of arguments to remove.
rename_args => hash

Arguments to rename.
replace_args => hash

Arguments to add.
summary => str

Summary for the mod subroutine.
wrap_code => code

Wrapper to generate the modified sub.

The modified sub will become:
```
sub { wrap_code->(base_code, @_) }
```
Alternatively you can use output_code. If both are not specified, will use base_code (which will then be required) as the modified subroutine's code.

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

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

Experimental.

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.

Examples:

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.

warn_err(...)

This is a shortcut for:

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

die_err(...)

This is a shortcut for:

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

FAQ

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;

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/Perinci-Sub-Util.

SOURCE

Source repository is at https://github.com/perlancar/perl-Perinci-Sub-Util.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTOR

Steven Haryanto <stevenharyanto@gmail.com>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

% prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

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

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=Perinci-Sub-Util

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.

To install Perinci::Sub::Util, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Perinci::Sub::Util

CPAN shell

perl -MCPAN -e shell
install Perinci::Sub::Util

For more information on module installation, please visit the detailed CPAN module installation guide.

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