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Perinci-CmdLine-Lite-0.19
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/ Perinci::CmdLine::Manual::Examples

NAME

Perinci::CmdLine::Manual::Examples - Collection of examples

VERSION

This document describes version 0.19 of Perinci::CmdLine::Manual::Examples (from Perl distribution Perinci-CmdLine-Lite), released on 2014-08-24.

DESCRIPTION

In the examples, Perinci::CmdLine::Any is used to show examples that are applicable to either Perinci::CmdLine or Perinci::CmdLine::Lite. For examples that are more appropriate or only applicable to specific implementation, the specific module will be used.

Perinci::CmdLine is hereby referred to as P::C, while Perinci::CmdLine as P::C::Lite.

Simplest application

Since Perinci::CmdLine is function- and metadata-based, you need to create at least one function and add some metadata for it. And you'll need to return the result as an enveloped response. The simplest is something like:

#!perl
use strict;
use warnings;
use Perinci::CmdLine::Any;

our %SPEC;
$SPEC{hello} = {
    v => 1.1,
    summary => 'Say hello',
};
sub hello {
    [200, "OK", "Hello, world!"];
}

Perinci::CmdLine::Any->new(url => '/main/hello')->run;

The url attribute specifies the location of the function in URL format (see Riap for more details on the syntax of URL). It is basically a fully-qualified function name, with :: replaced with /. With this URL-based syntax, it is possible to use a remote and/or non-Perl function for the CLI application.

The hash in $SPEC{hello} is called a Rinci metadata. The keys are called properties. There are two properties: v (which is always required with the value of 1.1 to specify version) and summary (which is actually optional, to describe the function).

In this example, the function and its metadata is put inside the same script. You can of course put them in a separate Perl module, and use them with e.g. url => '/Your/Module/func'. It is also worth mentioning that if you use the P::C framework, your functions can also be used directly by other Perl modules/code since they are just regular Perl functions.

The function returns a 3-element array containing HTTP-like status code, a status message, and the actual result.

If you save the above script as hello run it on the command-line:

% ./hello
Hello, world!

Yup, not very interesting. You get help message for free:

% ./hello --help
% ./hello -h

As well as some common options like --format to return the result in a different format:

% ./hello --json
[200,"OK","Hello, world!"]

% ./hello --format perl; # only in P::C, not available in P::C::Lite
[200, "OK", "Hello, world!"]

Function arguments (command-line options)

Function arguments map to command-line options. Example:

#!perl
use strict;
use warnings;
use Perinci::CmdLine::Any;

our %SPEC;
$SPEC{hello} = {
    v => 1.1,
    summary => 'Say hello',
    args => {
        name => {
            summary => 'Name to say hello to',
        },
    },
};
sub hello {
    my %args = @_;
    [200, "OK", "Hello, $args{name}!"];
}

Perinci::CmdLine::Any->new(url => '/main/hello')->run;

When you run this:

% ./hello --name Jimmy
Hello, Jimmy!

If you run ./hello --help, the option is now mentioned as well in the help message.

Unknown arguments will result in an error:

% ./hello --gender m
ERROR 400: Unknown option '--gender'

To specify that an argument is required, add req property to the argument specification with a true value:

args => {
    name => {
        summary => 'Name to say hello to',
        req => 1,
    },
},

So when you run the app:

% ./hello
ERROR 400: Missing required argument 'name'

To specify that an argument can also be specified via positional command-line argument instead of just command-line option, add pos property to the argument specification:

args => {
    name => {
        summary => 'Name to say hello to',
        req => 1,
        pos => 0,
    },
},

So when you run the app you can specify:

% ./hello --name Jimmy
Hello, Jimmy!

as well as:

% ./hello Jimmy
Hello, Jimmy!

Extra arguments will also result in an error:

% ./hello Jimmy Gideon
ERROR 400: Extra argument 'Gideon'

Argument schema (and more on text output formats)

Following up from the previous example, here's another example with more arguments. Also note that I use P::C since P::C::Lite doesn't do schema validation.

#!perl
use 5.010;
use strict;
use warnings;
use Perinci::CmdLine;

our %SPEC;
$SPEC{hello} = {
    v => 1.1,
    summary => 'Say hello',
    args => {
        name => {
            summary => 'Name(s) to say hello to',
            schema  => [array => {of => 'str', min_len=>1}],
            req     => 1,
            pos     => 0,
            greedy  => 1,
        },
        gender => {
            summary => 'The gender of the name(s)',
            schema  => [str => {in => ['m','f']}],
        },
    },
};
sub hello {
    my %args = @_;
    my $g = $args{gender};
    my @res;
    for my $name (@{ $args{name} // [] }) {
        push @res, join("",
            "Hello, ",
            (!$g ? "" : $g eq 'm' ? "Mr. " : "Mrs. "),
            $name, '!',
        );
    }
    [200, "OK", \@res];
}
Perinci::CmdLine->new(url => '/main/hello')->run;

If you run this program:

% ./hello Jimmy Sion Habil
% ./hello --name Jimmy --name Sion --name Habil
Hello, Jimmy!
Hello, Sion!
Hello, Habil!

% ./hello --name-json '["Jimmy","Sion","Habil"]' --gender m
Hello, Mr. Jimmy!
Hello, Mr. Sion!
Hello, Mr. Habil!

Some things you might notice. First, there is a schema property for each argument. name is specified as having a type of array of strings. To set this argument from the CLI, you can either specify multiple times (e.g. --name NAME1 --name NAME2 ...) or specify using JSON (i.e. --name-json JSONSTR).

Second, the name argument specifies the greedy property. This is used in conjunction with the pos property. It declares that the argument will gobble up command-line arguments from pos to the end. So you can also specify the values of the name argument with ARG1 ARG2 ....

Third, if you specify value that does not validate, an error will be produced.

% ./hello --name-json '[]'
ERROR 400: Invalid value for argument 'name': Length must be at least 1

% ./hello --name Jimmy --name Sion --name Habil --gender x
ERROR 400: Invalid value for argument 'gender': Must be one of ["m","f"]

See Data::Sah for more about the schema syntax.

Fourth, you return the result as a data structure (an array) instead of directly printing the result using print() or say(). This is done to make your function more reusable outside the context of CLI. P::C will format your data structure nicely using Data::Format::Pretty. Your array will be printed as a multicolumn ANSI table by default, on interactive mode. If you pipe the output of your program, you will by default get a simpler text output. This can be chosen explicitly using the --format common option.

% ./hello Jimmy Sion Habil --format text; # will output pretty or simple depending on whether interactive
% ./hello Jimmy Sion Habil --format text-simple; # will still output simple table even when interactive
% ./hello Jimmy Sion Habil --format text-pretty; # will still output pretty table even when piped

Short option aliases

To add short options, you can use the cmdline_aliases property in the argument specification:

name => {
    ...
    cmdline_aliases => { n => {} },
},
gender => {
    ...
    cmdline_aliases => { g => {} },
},

Now instead of:

% ./hello --name Jimmy --name Sion --name Habil --gender m

you can also use:

% ./hello -n Jimmy -n Sion -n Habil -g m

More on command-line option aliases

You are not limited to one alias, or one letter:

gender => {
    ...
    cmdline_aliases => { g => {}, sex => {} },
},

Now all these are equivalent:

% ./hello ... --gender m
% ./hello ... -g m
% ./hello ... --sex m

Suppose you want to create an alias -m to mean --gender m and -f to mean --gender f instead:

gender => {
    ...
    cmdline_aliases => {
        m => { schema=>'bool', code => sub {my $args=shift; $args->{gender} = 'm' } },
        f => { schema=>'bool', code => sub {my $args=shift; $args->{gender} = 'f' } },
    },
},

Now you can say:

% ./hello Jimmy Sion -m
Hello, Mr. Jimmy!
Hello, Mr. Sion!

% ./hello Nunung Misye -f
Hello, Mrs. Nunung!
Hello, Mrs. Misye!

Subcommands

Default subcommand

A default subcommand can be defined. This subcommand is selected without user specifying it the first command-line argument. A real-world example of this is from File::Trash::Undoable. The trash-u command is by default selecting the trash subcommand:

% trash-u file1 file2

is equivalent to:

% trash-u --cmd trash file1 file2

To select another subcommand other than trash, an explicit option is needed:

% trash-u --list-contents ; # select the list_contents subcommand
% trash-u --cmd empty     ; # select the empty subcommand

This is done via something like:

Perinci::CmdLine->new(
    subcommands => {
        trash => { url=>... },
        empty => { url=>... },
        list_contents => { url=>... },
    },
    default_subcommand => 'trash',
)->run;

Default subcommand (override via first command-line argument)

There is also a choice to specify a default subcommand which is overrideable via first command-line argument. A real-world example of this is from App::GitUtils. If the gu command is specified without any argument:

% gu

then it is equivalent to:

% gu info

but user can specify other subcommands:

% gu post-commit

This is accomplished by setting:

Perinci::CmdLine::Lite->new(
    subcommands => {
        info        => {...},
        run_hooks   => {...},
        post_commit => {...},
        ...
    },
    default_subcommand => 'info',
    get_subcommand_from_arg => 2,
)->run;

Dynamic list of subcommands

Getting input from STDIN

Getting input from file contents

Streaming output

Pager

Modifying common options

Customizing help message

Logging/debugging

Remote function

Shell tab completion

I18N

SEE ALSO

Perinci::CmdLine::Manual

HOMEPAGE

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

SOURCE

Source repository is at https://github.com/sharyanto/perl-Perinci-CmdLine-Lite.

BUGS

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

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.

AUTHOR

Steven Haryanto <stevenharyanto@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Steven Haryanto.

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