58e4d26648
Get rid of the separate opt-in IO class and replace it with a core System class. - Remove wren_io.c, wren_io.h, and io.wren. - Remove the flags that disable it. - Remove the overloads for print() with different arity. (It was an experiment, but I don't think it's that useful.) - Remove IO.read(). That will reappear using libuv in the CLI at some point. - Remove IO.time. Doesn't seem to have been used. - Update all of the tests, docs, etc. I'm sorry for all the breakage this causes, but I think "System" is a better name for this class (it makes it natural to add things like "System.gc()") and frees up "IO" for referring to the CLI's IO module.
3.2 KiB
^title Fiber Class ^category core
A lightweight coroutine. Here is a gentle introduction.
Fiber.new(function)
Creates a new fiber that executes function in a separate coroutine when the
fiber is run. Does not immediately start running the fiber.
:::dart
var fiber = Fiber.new {
System.print("I won't get printed")
}
Static Methods
Fiber.current
The currently executing fiber.
Fiber.suspend()
Pauses the current fiber, and stops the interpreter. Control returns to the host application.
To resume execution, the host application will need to invoke the interpreter again. If there is still a reference to the suspended fiber, it can be resumed.
Fiber.yield()
Pauses the current fiber and transfers control to the parent fiber. "Parent"
here means the last fiber that was started using call and not run.
:::dart
var fiber = Fiber.new {
System.print("Before yield")
Fiber.yield()
System.print("After yield")
}
fiber.call() // "Before yield"
System.print("After call") // "After call"
fiber.call() // "After yield"
When resumed, the parent fiber's call() method returns null.
If a yielded fiber is resumed by calling call() or run() with an argument,
yield() returns that value.
:::dart
var fiber = Fiber.new {
System.print(Fiber.yield()) // "value"
}
fiber.call() // Run until the first yield.
fiber.call("value") // Resume the fiber.
If it was resumed by calling call() or run() with no argument, it returns
null.
If there is no parent fiber to return to, this exits the interpreter. This can be useful to pause execution until the host application wants to resume it later.
:::dart
Fiber.yield()
System.print("this does not get reached")
Fiber.yield(value)
Similar to Fiber.yield but provides a value to return to the parent fiber's
call.
:::dart
var fiber = Fiber.new {
Fiber.yield("value")
}
System.print(fiber.call()) // "value"
Methods
call()
Starts or resumes the fiber if it is in a paused state.
:::dart
var fiber = Fiber.new {
System.print("Fiber called")
Fiber.yield()
System.print("Fiber called again")
}
fiber.call() // Start it.
fiber.call() // Resume after the yield() call.
When the called fiber yields, control is transferred back to the fiber that called it.
If the called fiber is resuming from a yield, the yield() method returns
null in the called fiber.
:::dart
var fiber = Fiber.new {
System.print(Fiber.yield())
}
fiber.call()
fiber.call() // Prints "null".
call(value)
Invokes the fiber or resumes the fiber if it is in a paused state and sets
value as the returned value of the fiber's call to yield.
:::dart
var fiber = Fiber.new {
System.print(Fiber.yield())
}
fiber.call()
fiber.call("value") // Prints "value".
isDone
Whether the fiber's main function has completed and the fiber can no longer be
run. This returns false if the fiber is currently running or has yielded.
transfer()
TODO
transfer(value)
TODO