Use Closure instead of callable for various methods of Routing package.

[ADmad]

I don't think anyone would be using invokable classes for connecting routes. For various router/routerbuilder methods we allow passing callback for 2nd params/options argument which is an array so using Closures only for callback are better for type checks.

[josegonzalez]

Its funny because I'm pretty sure I demo'd this exact thing - invokable classes for connected routes - a few years back for a microframework...

[markstory]

@josegonzalez Do you think we should retain compatibility for invokable classes to be used in route building? How does it help build a microframework app?

[josegonzalez]

I think its a nice way to evolve your app into a more complex one from simple closures. Here is a list of what slimphp supports, one of which is an invokable class.

I personally enjoy working with invokable classes as they can be registered easily and don't require a convention around the framework, instead relying on generic php :)

[ADmad]

While not clear from my comment my aim wasn't to prevent use of invokable but simply avoid callables as it covers a very wide range of values and callable checks can be expensive.

I can replace the \Closure typehint with object which would allow closures and invokable class instances. There are additional type checks already for type of $callback argument due the argument juggling in various methods so I will update the checks to allow invokables too.

[ADmad]

But using object typehint (or as docblock type) will most likely make static analyzers unhappy when trying to invoke the objects. Omitting typehint and specifying type as callable only in docblocks would be misleading as users my think all valid callables can be used 😞.

I wish PHP have a specific type for invokable classes 🙂.

[markstory]

Perhaps we should stick with callable given the awkward alternative typehints.

[ADmad]

Yup, there might be some clean up I can salvage out of this so I will keep this open for now and update the PR or close later.