Module: LambdaDriver::Callable

Included in:
Method, Proc, Symbol
Defined in:
lib/lambda_driver/callable.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(klass) ⇒ Object 



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# File 'lib/lambda_driver/callable.rb', line 86

def self.included(klass)
  klass.send(:alias_method, :+@, :to_proc)
  klass.send(:alias_method, :<,  :call)
  klass.send(:alias_method, :<<, :compose)
  klass.send(:alias_method, :*,  :with_args)
  klass.send(:alias_method, :~@, :flip)
  klass.send(:alias_method, :%, :curry)
end

Instance Method Details

#>>(g) ⇒ Object

g compose self



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# File 'lib/lambda_driver/callable.rb', line 28

def >>(g)
  g.to_proc << self
end

#call(*args, &block) ⇒ Object 



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# File 'lib/lambda_driver/callable.rb', line 3

def call(*args, &block)
  if block_given?
    self.to_proc.call(*args, &block)
  else
    self.to_proc.call(*args)
  end
end

#compose(g) ⇒ Object

Returns new lambda which composed self and given function. A composed proc called with args, executes ‘self.(g(*args)).

f = lamdba{|x| x.to_s }
g = lambda{|y| y.length }
h = f compose g
h.(:hoge) # => 4

This method is aliased as ‘<<`.

f << g # => f.compose(g)



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# File 'lib/lambda_driver/callable.rb', line 23

def compose(g)
  lambda{|*args| self.to_proc.call(g.to_proc.call(*args)) }
end

#curry(arity = nil) ⇒ Object 



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# File 'lib/lambda_driver/callable.rb', line 82

def curry(arity = nil)
  self.to_proc.curry(arity)
end

#flip(arity = nil) ⇒ Object

Returns function whose parameter order spawed 1st for 2nd. A result of filped fuction is curried by Proc#curry.

f = lamdba{|x, y, z| [x, y, z]}
h = f.flip
h.(:a).(:b).(:c) # => [:b, :a, :c]

If arguments is var-args, pass explicitly arity to curring.

p = Proc.new{|*args| args.inspect }
p.flip(3).call(:a).(:b).(:c)      # => "[:b, :a, :c]"
p.flip(4).call(:a).(:b).(:c).(:d) # => "[:b, :a, :c, :d]"

If arity is 0 or 1, flip returns itself.

This method is aliased as ‘~@`.

~f # => f.filp



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# File 'lib/lambda_driver/callable.rb', line 68

def flip(arity = nil)
  f = self.to_proc
  return self if (0..1).include?(f.arity)
  return self if f.arity == -1 && arity.nil?

  curried = f.curry(arity)
  lambda{|x|
    lambda{|y|
      g = curried[y]
      (g.respond_to? :call) ? g[x] : g
    }
  }
end

#with_args(*args) ⇒ Object

Returns partially applied function that has 2nd and more parameters fixed by given *args.

f = lamdba{|x, y, z| [x, y, z]}
h = f.with_args(:a, :b)
h.(:c) # => [:c, :a, :b]

This method is aliased as ‘*`.

f * :foo  # => f.with_args(:foo)



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# File 'lib/lambda_driver/callable.rb', line 43

def with_args(*args)
  lambda{|v|
    self.to_proc.call(*([v] + args))
  }
end