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vim9script
# VIM_TEST_SETUP let g:vimsyn_folding = "cfi"
# VIM_TEST_SETUP setl fdc=2 fdl=99 fdm=syntax
# VIM_TEST_SETUP hi link vim9DefTypeParam Todo
# See: https://github.com/vim/vim/pull/17313#issuecomment-3046696820 (Aliaksei Budavei)
# See https://github.com/vim/vim/pull/16604#issuecomment-265202845 .
export interface Listable
def Cons<E>(_: E): Listable
def Reverse<E>(): Listable
def Rest(): Listable
def First<E>(): E
def empty(): bool
def len(): number
def string(): string
endinterface
enum EmptyList implements Listable
INSTANCE
def Cons<E>(value: E): Listable
return List.new<E>(value)
enddef
def Reverse<E>(): Listable
return this
enddef
def Rest(): Listable
return this
enddef
def First<E>(): E
return null
enddef
def empty(): bool
return true
enddef
def len(): number
return 0
enddef
def string(): string
return '[]'
enddef
endenum
class List implements Listable
const _value: any
const _size: number
var _next: Listable
def new<E>(value: E)
this._value = value
this._size = 1
this._next = EmptyList.INSTANCE
enddef
def _newCons<E>(value: E, size: number)
this._value = value
this._size = size
enddef
def Cons<E>(value: E): Listable
const list: List = List._newCons<E>(value, (this._size + 1))
list._next = this
return list
enddef
def Reverse<E>(): Listable
var result: Listable = List.new<E>(this.First<E>())
var list: Listable = this.Rest()
while !list.empty()
result = result.Cons<E>(list.First<E>())
list = list.Rest()
endwhile
return result
enddef
def Rest(): Listable
return this._next
enddef
def First<E>(): E
return this._value
enddef
def empty(): bool
return (this._size == 0)
enddef
def len(): number
return this._size
enddef
def string(): string
if this.empty()
return '[]'
endif
var text: string = '[' .. string(this.First<any>()) .. ', '
var list: Listable = this.Rest()
while !list.empty()
text ..= string(list.First<any>()) .. ', '
list = list.Rest()
endwhile
return strpart(text, 0, (strlen(text) - 2)) .. ']'
enddef
endclass
export def MakeEmptyList(): Listable
return EmptyList.INSTANCE
enddef
export def MakeList<E>(value: E): Listable
return List.new<E>(value)
enddef
export def Map<T, U>(listable: Listable, Mapper: func(T): U): Listable
var result: Listable = EmptyList.INSTANCE
var list: Listable = listable
while !list.empty()
result = result.Cons<U>(Mapper(list.First<T>()))
list = list.Rest()
endwhile
return result.Reverse<U>()
enddef
export def Filter<T>(listable: Listable, Predicate: func(T): bool): Listable
var result: Listable = EmptyList.INSTANCE
var list: Listable = listable
while !list.empty()
if Predicate(list.First<T>())
result = result.Cons<T>(list.First<T>())
endif
list = list.Rest()
endwhile
return result.Reverse<T>()
enddef
############################################################
echo MakeEmptyList()
const listX: Listable = MakeEmptyList()
.Cons<number>(0).Cons<number>(1).Cons<number>(2).Cons<number>(3)
const listY: Listable = MakeList<number>(0)
.Cons<number>(1).Cons<number>(2).Cons<number>(3)
echo listX == listY
echo listX
echo listX.Reverse<number>()
echo MakeEmptyList().Reverse<any>()
echo Filter<number>(listX, (value: number) => value % 2 != 0)
echo Map<number, string>(listX, (value: number) => nr2char((value + 60), 1))
echo 4 listX.len() listY.len()
echo listX
echo listY
const list3X: Listable = listX.Rest()
const list3Y: Listable = listY.Rest()
echo 3 list3X.len() list3Y.len()
echo list3X
echo list3Y
const list2X: Listable = list3X.Rest()
const list2Y: Listable = list3Y.Rest()
echo 2 list2X.len() list2Y.len()
echo list2X
echo list2Y
const list1X: Listable = list2X.Rest()
const list1Y: Listable = list2Y.Rest()
echo 1 list1X.len() list1Y.len()
echo list1X
echo list1Y
const list0X: Listable = list1X.Rest()
const list0Y: Listable = list1Y.Rest()
echo 0 list0X.len() list0Y.len()
echo list0X
echo list0Y
const list0X_: Listable = list0X.Rest()
const list0Y_: Listable = list0Y.Rest()
echo 0 list0X_.len() list0Y_.len()
echo list0X_
echo list0Y_
const list0X__: Listable = list0X_.Rest()
const list0Y__: Listable = list0Y_.Rest()
echo 0 list0X__.len() list0Y__.len()
echo list0X__
echo list0Y__
const listZ: Listable = MakeList<Listable>(MakeList<number>(-1))
const listZZ: Listable = listZ.Cons<Listable>(MakeList<number>(0))
.Cons<Listable>(MakeList<number>(1))
.Cons<Listable>(MakeList<number>(2))
.Cons<Listable>(MakeList<number>(3))
echo listZZ
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