# HoboSupport

HoboSupport is a mixed bag of core ruby extensions that have been extracted from the [Hobo][] project

[Hobo]: http://hobocentral.net

    doctest_require: '../lib/hobosupport'
{.hidden}

    >> HoboSupport::VERSION
    => "1.1.0.pre0"

## Contents

 * [Enumerable](/manual/hobosupport/enumerable)
 * [Hash](/manual/hobosupport/hash)
 * [Implies](/manual/hobosupport/implies)
 * [Metaid](/manual/hobosupport/metaid)
 * [Methodphitamine](/manual/hobosupport/methodphitamine)
 * [Module](/manual/hobosupport/module)

## Object extensions

### `Object#is_one_of?`

Like `is_a?` but multiple types to be checked in one go

    >> "foo".is_one_of?(String, Symbol)
    => true
    >> :foo.is_one_of?(String, Symbol)
    => true
    >> 1.is_one_of?(String, Symbol)
    => false

## Method call extensions

We have the "." operator to call methods on objects. These extensions introduce two "special dots". 

### `Object#_?`

"`._?.`" only calls the method if the receiver is not `nil`.  Otherwise it returns nil.  So `x._?.method(*args)` is equivalent to `(nil == x ? nil : x.method(*args))`.

    >> "foo"._?.length
    => 3
    >> nil._?.length
    => nil

When the receiver is nil, any method with any arguments will return nil.  You can use Ruby's || idiom to provide a different value when nil.

    >> expires = nil
    >> expires._?.to_s( :default ) || "never"
    => "never"

Note that `_?` should *always* be followed by a method call.  It is not intended to store the intermediate result.  Don't do this!

intermediate = nil._?

### `Object#try`

"`.try`" only calls the method if the receiver responds to that method.  Otherwise it returns nil.  So `x.try.method(*args)` is equivalent to `(x.respond_to?(:method) ? x.method(*args) : nil)`.

    >> "foo".try.reverse
    => "oof"
    >> :foo.try.reverse
    => nil

### What's the difference?

Use `_?` when you want to call a method but you know the receiver may be nil.
Use `try` when you want to call a method but you know the receiver may not respond to it.  For instance, you
may use `try` to call a Rails 2.3 function that doesn't exist on Rails
2.2.  Note that nil responds to some functions that may surprise you.

    >> nil.try.to_i
    => 0
    >> nil._?.to_i
    => nil