deimos-lang/sketching/april_2025/closure.dm

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pub enum Closure(P, D = Any, S = Any) -> T {
Read(ReadClosure), // reads self (where Self is Closure) and/or environment
ReadRef(ReadRefClosure), // reads environment/self, return value tied to closure
Mut(MutClosure), // mutates self/environment
MutRef(MutRefClosure), // mutates self/environment, return value tied to closure
Cons(ConsClosure), // consumes self/environment
}
class Foo(bar: Bar) {}
class Bar(mut i: Int) {}
fn readClosure(cl: Closure(Int) -> String) -> String {
cl(42)
}
fn useReadClosure() {
let s = readClosure { i ->
'i: ' + i.toString()
}
assertEq('i: 42', s)
}
fn mutClosure(cl: mut Closure(Int) -> String) -> String {
cl(42)
}
fn useMutClosure() {
let mut x = 0
let cl: mut Closure(Int) -> String = mut { i ->
let result = 'Val: ' + (i + x)
x++
result
}
let s0 = mutClosure cl
assertEq('Val: 42', s0)
let s1 = mutClosure cl
assertEq('Val: 43', s1)
}
fn consClosure(cl: cons Closure(Int) -> String) -> String {
cl(42)
// cl(43) // Error! cl was already consumed
}
fn useConsClosure() {
let foo = Foo(Bar(10))
let cl: cons Closure(Int) -> String = cons { i ->
let fooBarI = foo.bar.i
drop(foo)
'Val: ' + (i + fooBarI)
}
let s = consClosure(cl)
// let err0 = consClosure(cl) // Error! cl may have been consumed
// let err1 = foo // Error! foo may have been consumed
assertEq('Val: 52', s)
}
fn readRefClosure(cl: Closure(foo: Foo) -> Bar ref foo) -> Int {
let foo = Foo(Bar(42))
let bar = cl(foo)
bar.i
}
fn useReadRefClosure() {
let i = readRefClosure { foo -> foo.bar }
assertEq(42, i)
}
fn mutRefClosure(cl: mut Closure(foo: Foo) -> Bar ref foo) -> Int {
let foo = Foo(Bar(42))
let bar = cl(foo)
bar.i
}
fn useMutRefClosure() {
let i = mutRefClosure mut { foo ->
foo.bar.i = 84
foo.bar
}
assertEq(84, i)
}
fn readClosureWithDelegate(cl: Closure(P = Int, D = Foo) -> String) -> String {
cl(42)
}
fn useReadClosureWithDelegate() {
let foo = Foo(Bar(42))
let cl = { i: Int ->
'Val: ' + (i + bar.i) // bar found in delegate
}
cl.delegate = &foo
let s = readClosureWithDelegate(cl)
assertEq('Val: 84', s)
}
class Baz(foo: Foo) {}
fn mutRefClosureWithDelegate(baz: &mut Baz, cl: Closure(Int, baz: &mut Baz)(D = Foo) -> &Bar ref baz) -> String {
let foo = Foo(Bar(1))
cl.delegate = &foo
let bar = cl(2, baz)
'Val: ' + bar.i
}
fn useMutRefClosureWithDelegate() {
let cl: Closure(Int, baz: &mut Baz)(D = Foo) -> &Bar ref baz = mut { i, baz ->
let iFromDelegate = bar.i
baz.foo.bar.i = iFromDelegate + i
&baz.foo.bar
}
let baz = Baz(Foo(Bar(20)))
let bar = mutRefClosureWithDelegate(cl)
assertEq(3, bar.i)
}
fn mutClosureWithDelegate(cl: Closure(P = (Int, Int), D = mut Foo) -> String {
let foo = Foo(Bar(42))
cl.delegate = &mut foo
cl(1, 2)
}
fn useMutClosureWithDelegate() {
let cl: Closure(P = (Int, Int), D = mut Foo) -> String = mut { x, y ->
bar.i = 3
'Val: ' + (x + y + bar.i)
}
let s = mutClosureWithDelegate(cl)
assertEq('Val: 6', s)
}
pub int ClosureBase {
params: Array<ClosureParam>
mut resolutionStrategy: ResolutionStrategy
ref fn getDelegate() -> Option<&Any>
ref fn getSelfObject() -> Option<&Any>
}
pub enum ResolutionStrategy {
DelegateFirst,
DelegateOnly,
SelfFirst,
SelfOnly,
None
}
pub int ConsClosure<T> : ClosureBase {
mut fn setDelegate(d: Any) -> Void
mut fn setSelf(s: Any) -> Void
mut fn call(...args: Array<Any>) -> T
def mut op () (...args: Array<Any) -> T = call(...args)
}
pub int MutClosure<T> : ClosureBase {
mut fn setDelegate(d: &mut Any) -> Void
mut fn setSelf(s: &mut Any) -> Void
mut fn call(...args: Array<Any>) -> T
def mut op () (...args: Array<Any>) -> T = call(...args)
}
pub int MutRefClosure<T> : ClosureBase {
mut fn setDelegate(d: &mut Any) -> Void
mut fn setSelf(s: &mut Any) -> Void
mut ref fn call(...args: Array<Any>) -> T // T ref self
def mut ref op () (...args: Array<Any>) -> T = call(...args)
}
pub int ReadClosure<T> : ClosureBase {
mut fn setDelegate(d: &Any) -> Void
mut fn setSelf(s: &Any) -> Void
fn call(...args: Array<Any>) -> T
def op () (...args: Array<Any>) -> T = call(...args)
}
pub int ReadRefClosure<T> : ClosureBase {
mut fn setDelegate(d: &Any) -> Void
mut fn setSelf(s: &Any) -> Void
ref fn call(...args: Array<Any>) -> T
def op () (...args) -> T = call(..args)
}
pub int ClosureParam {
clazz: Class<Any>
def op typeof () -> Class<Any> = clazz
}
// Example of how closures are compiled
fn main() {
let is = [1, 2, 3]
let cl0 = { acc: String, i: Int ->
acc + i
}
println is.reduce(cl0)
let x = 10
let cl1 = /* read */ { acc: String, i: Int ->
acc + (i + x)
}
println is.reduce(cl1)
let mut counter = 0
let cl2 = mut { acc: String, i: Int ->
let result = acc + (i + counter)
counter++
result
}
println is.reduce(cl2)
let mut foo = Foo(Bar(1))
let cl3 = cons { acc: String, i: Int ->
// do something pointless just for illustration
if foo.bar.y % 2 == 0 {
foo.bar = Bar(1)
}
let result = acc + (i + foo.bar.y)
foo.bar.y++
result
}
// foo.bar = Bar(42) // Error! foo moved into consuming cl3
println [1, 2, 3, 4].reduce(cl3) // "11243645"
}
// Compiled
@Synthetic
fn closure_main_cl0(acc: String, i: Int) = acc + i
@Synthetic
class Closure_main_cl1_env(x: &Int) -> String {}
@Synthetic
class Closure_main_cl1(env: Closure_main_cl1_env) : ReadClosure<String> {
impl fn call(...args: Array<Any>) -> String {
let acc: String = args[0]
let i: Int = args[1]
let x: Int = *env.x // because env.getX() -> &&Int
acc + (i + x)
}
}
@Synthetic
class Closure_main_cl2_env(counter: &mut Int) {}
@Synthetic
class Closure_main_cl2(env: Closure_main_cl2_env) : MutClosure<String> {
impl mut fn call(...args: Array<Any>) -> String {
let acc: String = args[0]
let i: Int = args[1]
let counter = &mut env.counter
let result = acc + (i + counter)
*counter++
result
}
}
@Synthetic
class Closure_main_cl3(mut foo: Foo) : ConsClosure<String> {
impl mut fn call(...args: Array<Any>) -> String {
let acc: String = args[0]
let i: Int = args[1]
if foo.bar.y % 3 == 0 {
foo.bar = Bar(1)
}
let result = acc + (i + foo.bar.y)
foo.bar.y++
result
}
}
fn main() {
let is: List<Int> = ArrayList() {
add 1
add 2
add 3
}
let cl0 = &closure_main_cl0
println is.reduce(cl0)
let x = 10
let cl1_env = HashMap() {
put 'x', &x
}
let cl1: Closure<String> = Closure::ReadClosure(Closure_main_cl1(cl1_env))
println is.reduce(cl1)
let mut counter = 0
let cl2_env = Closure_main_cl2_env(&counter)
let cl2: Closure<String> = Closure::MutClosure(Closure_main_cl2(cl2_env))
println is.reduce(cl2)
let mut foo = Foo(Bar(1))
let cl3: Closure<String> = Closure::ConsClosure(Closure_main_cl3(foo)) // foo moved into closure
let tmp0: List<Int> = ArrayList() {
addAll 1, 2, 3, 4
}
println tmp0.reduce(cl3)
}
// Example
// original
class Foo {
mut fld current = 0
ref fn getClosure(base: Int) -> (mut Closure(Int) -> Int) {
return mut { given ->
let result = base + given + current
current++
result
}
}
}
fn main() {
let foo = Foo()
let cl = foo.getClosure(10)
let nums = [cl(1), cl(2), cl(3), cl(4)]
assertEq([11, 13, 15, 17], nums)
}
// Compiles to
@Synthetic
class Closure_Foo_getClosure_0(base: &Int, current: &mut Int) : MutClosure(Int) -> Int {
impl mut fn call(given: Int) -> Int {
let result = *base + given + *current
*current++
result
}
}
class Foo {
mut fld current = 0
ref fn getClosure(base: Int) -> (mut Closure(Int) -> Int) {
return Closure_Foo_getClosure_0(&base, &mut current)
}
}
fn main() {
/* ... */
}
// Library code
pub int ReadClosure(P : () = ())<T, D = Any, S = Any> : Into[Self(P)<T, D, S>, Option<D>] {
mut fn setDelegate(d: D) -> Void
ref fn getDelegate() -> Option<&D>
mut fn setSelfObject(s: &S) -> Void
ref fn getSelfObject() -> Option<&S>
fn call(...params: P) -> T
def op () (...params: P) -> T = call(...params)
def cons fn intoDelegate() -> D {
Into[Self(P)<T, D, S>, Option<D>].into()
}
}
pub abstract class AbstractReadClosure(P : () = ())<T, D = Any, S = Any> : ReadClosure(P)<T, D, S> {
mut fld delegate: Option<D>
mut fld selfObject: Option<&S>
impl mut fn setDelegate(d: D) {
delegate = Some(d)
}
impl ref fn getDelegate() -> Option<&D> {
&delegate is Some(d) ? Some(d) : None
}
impl mut fn setSelfObject(s: &S) {
selfObject = Some(s)
}
impl ref fn getSelfObject() -> Option<&S> {
&selfObject is Some(s) ? Some(s) : None
}
impl Into[Self(P)<T, D, S>, D] {
cons fn into() -> Option<D> = delegate
}
}
// User code demonstration
class Foo(bar: Bar) {}
class Bar(num: Int) {}
class Baz(foo: Foo) {
pub ref fn getClosure() -> Closure<Int, D = Foo> {
return { foo.bar.num + bar.num }
}
}
fn main() {
let baz0 = Baz(Foo(Bar(1)))
let cl = baz0.getClosure()
let delegate = Foo(Bar(2))
cl.delegate = delegate
let result0 = cl()
assertEq(3, result0)
let baz1 = Baz(Foo(Bar(2)))
cl.selfObject = &baz1
let result1 = cl()
assertEq(4, result1)
let movedDelegate = cl.intoDelegate()
assertEq(2, movedDelegate.bar.num)
}
// User code compiles to
class Foo(bar: Bar) {}
class Bar(num: Int) {}
@Synthetic
class Closure_Baz_getClosure_0: AbstractReadClosure()<Int, D = Foo> {
ctor(selfObject: &Baz) ref selfObject {
self.selfObject = Some(selfObject)
}
fn call() -> Int {
let t0 = selfObject.unwrap().foo.bar.num
let t1 = self.delegate.unwrap().bar.num
t0 + t1
}
}
class Baz(foo: Foo) {
pub ref fn getClosure() -> Closure<Int, D = Foo> {
return Closure_Baz_getClosure_0(&self)
}
}
fn main() {
// ...
}
// fn vs Closure syntax
int FnOrClosureTaker {
fn read(f: fn (Int) -> Int) -> Int
fn mut(f: mut fn (Int) -> Int) -> Int
fn cons(f: cons fn (Int) -> Int) -> Int
}
class FnOrClosureTakerImpl : FnOrClosureTaker {
impl fn read(f: fn (Int) -> Int) {
let i0 = f(0)
let i1 = f(1)
let i2 = f(2)
i0 + i1 + i2
}
impl fn mut(f: mut fn (Int) -> Int) {
/* same as read */
}
impl fn cons(f: cons fn (Int) -> Int) {
let i0 = f()
// let i1 = f() // Error! f already consumed
i0
}
}
mod User {
fn getReader() -> fn (Int) -> Int {
return { it * 2 }
}
fn useReader() {
let reader = getReader()
let fnOrClosureTaker: FnOrClosureTaker = FnOrClosureTakerImpl()
let result = fnOrClosureTaker.read(reader)
assertEq(6, result)
}
}
// compiles to
mod User {
fn getReader_closure_0(it: Int) -> Int {
it * 2
}
fn getReader() -> &fn (Int) -> Int {
&getReader_closure_0
}
// etc.
}
// New interfaces?
pub int ReadClosure(P : () = ())<D> -> T : fn (P) -> T {
ref fn getDelegate() -> Option<&D>
mut fn setDelegate(d: D) -> Void
fn call(...p: P) -> T
def op () alias call
}
pub int Iterator<T> {
mut fn next() -> Option<T>
}
pub int Iterable<T> : Into[Self<T>, Iterator<T>] {
ref fn iterator() -> Iterator<&T>
def cons fn intoIterator() = Into[Self, Iterator].into(self)
}
pub class MyIterable : Iterable<Int> {
fld items: List<Int> = [1, 2, 3]
impl ref fn iterator() -> Iterator<&Int> {
let mut index = 0
return mut {
if index >= items.length {
None
} else {
let next = items[index]
index++
Some(next)
}
}
}
}