Module: Isy::Methods

Defined in:
lib/isy/methods.rb

Instance Method Summary collapse

Instance Method Details

#isy(subject, evaluation = nil, &block) ⇒ Object

Isy::Methods#isy

The primary use of Isy is through the #isy method, which is included into Object upon initialization

Usage

You can call isy from any point, but it’s intended use is to be treated like a “guard clause” to assert method argument types before those arguments are used (and potentially wreak havoc throughout the implementation:

def fullname segments
  isy segments, Array
end

The first argument is the subject of the test (i.e. what should match the proceeding assertion) The second argument is the type.

If the subject doesn’t match the provided type, then it raises a formatted exception describing what argument value was a type mismatch (as an ‘Isy::ArgumentTypeMismatch` exception).

Usage with an operation

Optionally, in place of a type as the second argument, you can pass a block, and perform a more complex comparison operation:

def fullname segments
  isy segments { |seg| seg.length == 3 }
end

As illustrated above, ‘isy` yields to the operation the first argument (segments). The expectation is that the value returned by the operation (block) is a boolen (true => passes, false => failed).



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# File 'lib/isy/methods.rb', line 37

def isy subject, evaluation=nil, &block
  unless isy? subject, evaluation, &block
    raise Isy::ArgumentTypeMismatch.new(
      subject: subject,
      caller_method: caller_locations(1,1)[0].label
    )
  end
end

#isy?(subject, evaluation = nil, &block) ⇒ Boolean

Isy::Methods#isy?

Usage

The implementation follows the same workflow as ‘isy` with one exception (pun intended): returns a boolen.

def fullname segments
  if isy? segments, Array
    # passes
  end
end

If the subject doesn’t match the provided type, then it returns false

Usage with an operation

Optionally, in place of a type as the second argument, you can pass a block, and perform a more complex comparison operation:

def fullname segments
  isy? segments { |seg| seg.length == 3 }
end

As illustrated above, ‘isy?` yields to the operation the first argument (segments). The expectation is that the value returned by the operation (block) is a boolen (true => passes, false => failed).

Returns:

  • (Boolean) 


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# File 'lib/isy/methods.rb', line 72

def isy? subject, evaluation=nil, &block
  tester = block || evaluation

  unless tester
    raise ArgumentError,
      'Object#isy requires either a type or evaluation block'
  end

  tester === subject
end