method

returning

v2.3.8 - Show latest stable - 2 notes - Class: Object

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What's this?

returning(value) public

Returns value after yielding value to the block. This simplifies the process of constructing an object, performing work on the object, and then returning the object from a method. It is a Ruby-ized realization of the K combinator, courtesy of Mikael Brockman.

Examples

 # Without returning def foo values = [] values << "bar" values << "baz" return values end foo # => ['bar', 'baz'] # returning with a local variable def foo returning values = [] do values << 'bar' values << 'baz' end end foo # => ['bar', 'baz'] # returning with a block argument def foo returning [] do |values| values << 'bar' values << 'baz' end end foo # => ['bar', 'baz']

Show source

# File activesupport/lib/active_support/core_ext/object/misc.rb, line 38 def returning(value) yield(value) value end

January 8, 2009

5 thanks

Watch out for syntax errors

Watch out when you are using returning with hashes. If you would write code like

def foo(bars) returning {} do |map| bars.each { |bar| map[bar.first] = bar } end end

you will get a syntax error since it looks like you tried to supply two blocks! Instead you should write it with parenthesis around the hash:

def foo(bars) returning({}) do |map| bars.each { |bar| map[bar.first] = bar } end end

July 23, 2012

0 thanks

Replacement

# Method using returning can replaced def foo returning Hash.new do |h| h[:foo] = "bar" end end # By method using tap  def foo Hash.new.tap do |h| h[:foo] = "bar" end end

returning

Related methods

Examples

Watch out for syntax errors

Replacement

Replacement