Module: Core

Included in:
F
Defined in:
lib/fubby/core.rb

Instance Method Summary collapse

Instance Method Details

#compose ⇒ Object

TODO: figure out how to notate many args. [f] isn’t correct here.

compose
f

-> (a -> b)



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# File 'lib/fubby/core.rb', line 44

def compose
  ->(*f) {
    _compose = ->(x, *f) {
      f.length == 1 ? f[0].(x) : f[0].(_compose.(x, *f[1..-1]))
    }

    ->(x) { _compose.(x, *f) }
  }
end

#curry ⇒ Object

curry

(a -> b) -> (a -> b)



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# File 'lib/fubby/core.rb', line 8

def curry
  _curry = ->(f, *given_args) {
    ->(*remaining_args) {
      total_args = given_args + remaining_args

      total_args.length == f.arity ? f.(*total_args) : _curry.(f, *total_args)
    }
  }

  ->(f) {
    ->(*x) {
      f.arity == x.length ? f.(*x) : _curry.(f, *x)
    }
  }
end

#flip ⇒ Object

flip

(a -> b) -> (a -> b)



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# File 'lib/fubby/core.rb', line 55

def flip
  ->(f) {
    ->(*args) {
      f.(*reverse.(args))
    }
  }
end

#identity ⇒ Object

identity

a -> a



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# File 'lib/fubby/core.rb', line 3

def identity
  ->(x) { x }
end

#reduce ⇒ Object

reduce

a, (b -> a), [b] -> a



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# File 'lib/fubby/core.rb', line 25

def reduce
  curry.(->(memo, f, array) {
    if memo == nil
      case array.length
      when 0 then nil
      when 1 then array[0]
      else reduce.(f.(array[0], array[1]), f, array[2..-1])
      end
    else
      case array.length
      when 0 then memo
      else reduce.(f.(memo, array[0]), f, array[1..-1])
      end
    end
  })
end