Add requires

[enygma]

Adding the concept of "required options". Adds dependency between options such that:

$cmd = new Command();
$cmd->option('test')
->requires('other');

So that if "--test" is defined, "--other" must be also otherwise an exception is thrown. Options can also have multiple dependencies:

$cmd = new Command();
$cmd->option('test')
->requires(array('other','option'));

Where both "--other" and "--option" must be defined.
Unit tests are included.

[mackenza]

I think this is an interesting addition but I wonder about calling it "requires" since there is already a command method by that name.

How about "dependsOn" or something like that?

[enygma]

I'm good with that...happy to make that change.

[mackenza]

note that I am just a user of commando not directly associated with the project ;) @nategood needs to be the one to weigh in on the PR.

I was looking further at this and had a thought... yes, dependsOn() is better than requires() as it would surely get confused with require(), but what if we just overload require()? for example:

// option 'test' is required for $cmd
$cmd = new Command();
$cmd->option('test')
->require(true, NULL);

// option 'test' is required for $cmd and option 'foo' is required with option 'test'
$cmd = new Command();
$cmd->option('test')
->require(true,'foo');

// option 'test' is optional for $cmd but option 'foo' is required *if* 'test' is present
$cmd = new Command();
$cmd->option('test')
->require(false,'foo');

// option 'test' is required for $cmd and options 'foo' + 'bar' are also required with option 'test'
$cmd = new Command();
$cmd->option('test')
->require(true,array('foo','bar'));

// option 'test' is optional for $cmd but options 'foo' + 'bar' are required *if* option 'test' is present
$cmd = new Command();
$cmd->option('test')
->require(true,array('foo','bar'));

Maybe this is too complex but I like it as many different dependency use cases can be covered by a single option.

[enygma]

It's an interesting idea, but I wonder if it's missing too many "require" contexts into on place since it'd be both: "this option is required" and "If you use this, you're required to use these others". I don't know if the (subtle?) distinction between them is enough to warrant them being different though.

[mackenza]

I guess the way I was thinking about it was: The require() specifies all the dependencies of this option() or flag()... including the dependency on itself.

But you are right, it could be too subtle. Just a thought.

[enygma]

It would't take much to use what I've already put in there and overload the requires, really...it could be done either way and have the same effect.

[nategood]

Thanks for adding this! Sorry for not chiming in earlier. I generally tend to lean towards explicitness and readability. I think @enygma also has a point w.r.t. coupling general require behavior with dependency behavior. For these reasons, I like the idea of a new method.

Agree requires is too close to require. I'm not sure dependsOn is the most descriptive name IMO. How about needs?

$cmd = new Command();
$cmd->option('test')
  ->require()
  ->needs('foo','bar');

[enygma]

Works for me on the "needs"....I wonder about that syntax though. Personally, I think if there's more than one defined it should be given in an array to avoid the need for something like func_get_args to work with a variable number of parameters.

[nategood]

Agree. The array syntax would be more appropriate.

[enygma]

Give that a shot...

[nategood]

Great! Merged. Will update docs, version, etc. shortly.

[enygma]

Nice! Thanks for including this in the project :)