== Summary
methodchain - ruby helpers for method chaining: chain, tap, then, else
Easy ways to navigate around nil without creating local variables.

== Author and License
Copyright (c) 2008 Greg Weber, http://gregweber.info
Licensed under the MIT license

== Examples
==== tap
if you don't already know about this method, look it up on the net.  The tap included here allows message sending.

OLD WAY (still valid with this tap)
  [1].tap {|arr| arr.compact!}.first # => 1
NEW WAY
  [1].tap(:compact!).first # => 1

==== #then and #else
OLD WAY

  name = person ? person.name : nil

NEW WaY

  name = person.then {|p| p.name}

not a huge savings. But sometimes the person variable is actually a function call, and then we must save it in a variable first.

OLD WAY

  location = Location.find(:first, ...)
  @phone = location && location.phone

NEW WaY

  @phone = Location.find(:first, ...).then {phone}
  
here we have reduced a line of code and removed a local variable
#then and #else can return a default value instead of evaluating a block
'a'.then('b') #=> 'b'
nil.then('b').else('c') #=> 'c'

=== #chain
OLD WAY

  customer && customer.order && customer.order.id

NEW WaY

  customer.chain(:order, :id)
 
note that this is equivalent to

  customer.then {order}.then {id}

=== chain - Custom guards and multiple argumentes
OLD WAY - guarding against zero

  result = if value == 0 then value else
    tmp = calc(value)

    if tmp == 0 then tmp else
      more_calc(tmp, 20)
    end
  end

NEW WAY
  value.chain(:calc, [:more_calc, 20]) {|s| s == 0 }

== Usage
  require 'rubygems'

=== import all MethodChain methods into Object

  require 'methodchain'

=== selectively import MethodChain methods

  require 'methodchain/not_included'

not_included will load the MethodChain module without including it anywhere.
Already have your own version of tap? use the module-import gem to decide what to include

== Implementation
* There are no proxy objects and no use of method_missing- these are simply function calls, so it should be fast.
* A helper method called self_eval is also exposed.  This method allows the two different block forms {|p| p.name} and {name}, where the first form yields self and the second form is called using instance_eval.

== Install
gem install methodchain

== Source
=== browser
http://github.com/gregwebs/methodchain/tree/master
=== repository
git clone git://github.com/gregwebs/methodchain.git

== Homepage
http://gregweber.info/projects/methodchain.html

== RDoc documentation
included with gem