var key = R.prop('key')
var value = R.prop('value')
var window2 = R.aperture(2)

function bind0(rootSelection, cssClass, element, dataFlow) {
    element = element || 'g' // fixme switch from variadic to curried
    dataFlow = typeof dataFlow === 'function' ? dataFlow
        : (dataFlow === void(0) ? function(d) {return [d]} : R.always(dataFlow))
    var binding = rootSelection.selectAll('.' + cssClass).data(dataFlow, key)

    binding.entered = binding.enter().append(element)
    binding.entered.classed(cssClass, true)

    return binding
}

function bind(object, key) {
    var result = bind0.apply(null, arguments)
    object[key] = result
    return result
}

function translate(funX, funY) {
    return function(d, i) {
        var x = typeof funX === 'function' ? funX(d, i) : funX
        var y = typeof funY === 'function' ? funY(d, i) : funY
        if(isNaN(x)) throw Error('x is NaN')
        if(isNaN(y)) throw Error('y is NaN')
        return 'translate(' + x + ',' + y + ')'
    }
}

function translateX(funX) {
    return function(d, i) {
        return 'translate(' + (typeof funX === 'function' ? funX(d, i) : funX) + ', 0)'
    }
}

function translateY(funY) {
    return function(d, i) {
        return 'translate(0, ' + (typeof funY === 'function' ? funY(d, i) : funY) + ')'
    }
}