import .collection.Collection

extend Array
    is Collection

    method + x
       x addArray: self
    method - x
       x subArray: self
    method * x
       x mulArray: self
    method / x
       x divArray: self

    method first
       self at: 1

    method second
       self at: 2

    method _emitOn: stream using: block
        stream writeUTF8: "[".
        let first = True.
        self do: { |x|
                   first
                     ifTrue: { first = False }
                     ifFalse: { stream writeUTF8: ", " }.
                   block value: x }.
        stream writeUTF8: "]"

    method displayOn: stream
        self _emitOn: stream using: { |x| x displayOn: stream }

    method printOn: stream
        self _emitOn: stream using: { |x| x printOn: stream }

    method norm
       (self inject: 0.0 into: { |abs elt| abs + (elt square) }) sqrt

    method normalized
       let reciprocal = 1.0 / (self norm).
       self * reciprocal

    method scalarProjectionOn: other
        (self dot: other) / other norm

    method vectorProjectionOn: other
        ((self dot: other) / (other dot: other)) * other

    method do: block
        self inject: False into: { |dummy elt| block value: elt }.
        self

    method collect: block
        self inject: [] into: { |res elt| res push: (block value: elt) }

    method sum
        self inject: 0 into: { |res elt| res + elt }

    method sum: block
        self inject: 0 into: { |res elt| res + (block value: elt) }

    method addInteger: x
       self collect: { |elt| elt addInteger: x }
    method addFloat: x
       self collect: { |elt| elt addFloat: x }

    method divFloat: x
       self collect: { |elt| elt divFloat: x }
    method divInteger: x
       self collect: { |elt| elt divInteger: x }

    method mulInteger: x
       self collect: { |elt| elt mulInteger: x }
    method mulFloat: x
       self collect: { |elt| elt mulFloat: x }

    method subInteger: x
       self collect: { |elt| elt subInteger: x }
    method subFloat: x
       self collect: { |elt| elt subFloat: x }
end