async — examples
← all topics · 126 examples · page 3 of 3 · raw source ↓
Runs `gap4field` → 1
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: SymbolSpineTests.cs::AsyncMethods_AsyncSiblingIntoTaskField topic: async status: verified
// verified behavior: Test.gap4field(...) == 1
namespace Test
class Svc {
var worker: Task
var n: int
init() { self.n = 0 }
func work() -> Task { await Task.Delay(1) }
func start() { self.worker = self.work() }
}
func gap4field() -> int {
let s = Svc()
s.start()
return 1
}Runs `gap4fwd` → 1
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: SymbolSpineTests.cs::AsyncMethods_ForwardDeclaredAsyncSibling_Resolves topic: async status: verified
// verified behavior: Test.gap4fwd(...) == 1
namespace Test
class Svc {
var worker: Task
var n: int
init() { self.n = 0 }
func start() { self.worker = self.run(2) }
func run(k: int) -> Task { await Task.Delay(k) }
}
func gap4fwd() -> int {
let s = Svc()
s.start()
s.worker.Wait()
return 1
}Runs `gap4` → 1
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: SymbolSpineTests.cs::AsyncMethods_SelfAsyncSiblingCall_Resolves topic: async status: verified
// verified behavior: Test.gap4(...) == 1
namespace Test
class Svc {
var n: int
init() { self.n = 0 }
func work() -> Task { await Task.Delay(1) }
func kick() {
let running = self.work()
running.Wait()
}
}
func gap4() -> int {
let s = Svc()
s.kick()
return 1
}Runs `gap4ss` → 2
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: SymbolSpineTests.cs::AsyncMethods_StartStorThenAwaitStored topic: async status: verified
// verified behavior: Test.gap4ss(...) == 2
namespace Test
class Svc {
var worker: Task
var n: int
init() { self.n = 0 }
func run() -> Task { await Task.Delay(1) }
func start() { self.worker = self.run() }
func stop() -> Task { await self.worker }
}
func gap4ss() -> int {
let s = Svc()
s.start()
let t = s.stop()
t.Wait()
return 2
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: TranspilerTests.cs::Transpiles_Chan_Creation topic: async status: verified
// compiles cleanly (no auto-run claim was extracted)
namespace Audit
pub func makeChan() -> Chan<string> {
let ch = chan<string>(256)
return ch
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: TypeGrammarTests.cs::Chan_AnnotatedParamRoundTrip topic: async status: verified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func pump(ch: chan<int>, v: int) { ch.Send(v) }
func go() -> int {
let ch = chan<int>(1)
pump(ch, 13)
var v = 0
if ch.TryReceive(out v) { return v }
return -1
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: TypeGrammarTests.cs::Select_DefaultArm_FiresOnEmptyChannel topic: async status: verified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func go() -> int {
let ch = chan<int>(1)
var fired = 0
select {
.recv(v, ch) { fired = 1 }
default { fired = 99 }
}
return fired
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: TypeGrammarTests.cs::Select_RecvArm_FiresOnReadyChannel topic: async status: verified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func go() -> int {
let ch = chan<int>(1)
ch.Send(42)
var got = 0
select {
.recv(v, ch) { got = v }
default { got = -1 }
}
return got
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: EmitterStressTests.cs::AsyncWithTupleReturnAndForDestructuring topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace T
func work() -> (List<string>, List<string>) {
var items = List<string>()
var errors = List<string>()
return (items, errors)
}
func run() {
var tasks = List<Task<(List<string>, List<string>)>>()
tasks.Add(Task.Run(func() -> (List<string>, List<string>) { return work() }))
let results = await Task.WhenAll(tasks.ToArray())
for (items, errors) in results {
let n = items.Count + errors.Count
}
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: EmitterStressTests.cs::RefDataWithAsyncMethodAndTryCatch topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace T
struct Item(title: string, source: string)
func fetchItems(client: HttpClient, url: string) -> (List<Item>, List<string>) {
var items = List<Item>()
var errors = List<string>()
try {
let stream = await client.GetStreamAsync(url)
items.Add(Item("title", "src"))
} catch (Exception ex) {
errors.Add(ex.Message)
}
return (items, errors)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: EmitterStressTests.cs::RefDataWithMultipleMethodsAndExpressionBodies topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace T
struct Config(name: string, url: string)
struct Item(title: string, source: string)
struct Status(name: string, itemCount: int)
class Svc {
configs: List<Config>
items: List<Item>
statuses: List<Status>
client: HttpClient
maxItems: int
init() {
self.configs = List<Config>()
self.items = List<Item>()
self.statuses = List<Status>()
self.client = HttpClient()
self.maxItems = 500
}
func poll() {
var tasks = List<Task<(List<Item>, List<string>)>>()
for cfg in self.configs {
let c = self.client
let f = cfg
tasks.Add(Task.Run(func() -> (List<Item>, List<string>) { return (List<Item>(), List<string>()) }))
}
let results = await Task.WhenAll(tasks.ToArray())
var all = List<Item>()
var statuses = List<Status>()
var i = 0
for (items, errors) in results {
let cfg = self.configs[i]
i += 1
let err = errors.Count > 0 ? errors[0] : ""
statuses.Add(Status(cfg.name, items.Count))
all.AddRange(items)
}
if all.Count > self.maxItems {
all.RemoveRange(self.maxItems, all.Count - self.maxItems)
}
self.items = all
self.statuses = statuses
}
func count() -> int = self.items.Count
func addConfig(name: string, url: string) = self.configs.Add(Config(name, url))
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: FeatureMixingTests.cs::Axis1_AsyncResultMatch_BadPattern_DiagnosesUnawaitedAsyncCall topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func parseAsync(s: string) -> int {
let v = await Task.FromResult(int.Parse(s))
return v
}
func safeParse(s: string) -> Result<int, string> {
let n = parseAsync(s)
return ok(n)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests.cs::Await_Binder_SetsHasAwait topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func fetch() -> string {
let x = await someCall()
return x
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests.cs::Await_Parser_ParsesAwaitExpression topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func fetch() -> string {
let x = await someTask()
return x
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests.cs::Emit_AsyncFunctionWithAwait topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace T
func fetch() -> Task<string> {
let client = HttpClient()
let result = await client.GetStringAsync("http://example.com")
return result
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests.cs::Emit_ComplexRefDataWithAsyncAndLambdas topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace T
func work() -> (List<string>, List<string>) {
var items = List<string>()
var errors = List<string>()
return (items, errors)
}
func run() {
var tasks = List<Task<(List<string>, List<string>)>>()
tasks.Add(Task.Run(func() -> (List<string>, List<string>) { return work() }))
let results = await Task.WhenAll(tasks.ToArray())
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncLet_OrderIndependentUse topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(1)
async let b = loadAsync(2)
let bv = b?
let av = a?
return ok(av + bv)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncLet_ResultInterpolatedAfterUnwrap topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(2)
async let b = loadAsync(2)
let av = a?
let bv = b?
let total = av + bv
return ok(total)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncLet_SecondError_Propagates topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(3)
async let b = loadAsync(0 - 9)
let av = a?
let bv = b?
return ok(av + bv)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncUserFn_FirstError_ShortCircuits topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(5)
async let b = loadAsync(0 - 1)
let av = a?
let bv = b?
return ok(av + bv)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncUserFn_SingleAsyncLet topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(7)
let av = a?
return ok(av)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncUserFn_ThreePending topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(1)
async let b = loadAsync(2)
async let c = loadAsync(3)
let av = a?
let bv = b?
let cv = c?
return ok(av + bv + cv)
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_AsyncLetMix.cs::AsyncUserFn_TwoPending_OkFold topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
func combine() -> Result<int, string> {
async let a = loadAsync(2)
async let b = loadAsync(3)
let av = a?
let bv = b?
return ok(av + bv)
}Rejected at compile time: ES2130
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_TaskFunc.cs::TaskFunc_Let_Capture_In_Function_Literal_Is_OK topic: async status: unverified
// verified behavior: reports diagnostic ES2130
namespace Test
task func go() {
let value = 7
let read = func() -> int { return value }
let v = read()
}Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: ILEmitterTests_TaskFunc.cs::TaskFunc_With_Parameters_Reports_NotYetSupported topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
task func with_arg(n: int) -> int { return n }Compiles
// E# — a verified example from the E# language corpus (CLR language; .es, not ECMAScript).
// provenance: TypeGrammarTests.cs::SelectArm_UnknownKind_Reports topic: async status: unverified
// compiles cleanly (no auto-run claim was extracted)
namespace Test
func go() {
let ch = chan<int>(1)
select {
.poll(v, ch) { }
default { }
}
}