// revCons appends acc to the head of curr, where acc is in reverse order.
// acc must never be nil, curr can be.
func revCons(acc, curr ps.List) ps.List {
if curr == nil {
return acc.Reverse()
}
for !acc.IsNil() {
acc, curr = acc.Tail(), curr.Cons(acc.Head())
}
return curr
}
// Extend behaves like Append, except it takes a single slice or array value
// which will be concatenated to the named list.
//
// Unlike a variadic call to Append - which requires a []interface{} value -
// Extend accepts slices or arrays of any type.
//
// Extend will panic if the given value is not a slice, array, or nil.
func Extend(builder interface{}, name string, vs interface{}) interface{} {
if vs == nil {
return builder
}
maybeList, ok := getBuilderMap(builder).Lookup(name)
var list ps.List
if ok {
list, ok = maybeList.(ps.List)
}
if !ok {
list = ps.NewList()
}
forEach(vs, func(v interface{}) {
list = list.Cons(v)
})
return Set(builder, name, list)
}