Subroutine Closure provides a sufficient foundation for /cons/truction of Coroutines. The rest is Sintactic sugar. For example Python "yield"... whatever is orwellian!!
On Mon, Jun 10, 2024, 12:16 Alexander Burger <picolisp@software-lab.de> wrote: > Hi František, > > > I've used the following method in other programming languages (Lua, > Janet) > > and I'm wondering whether I can do something similar in PicoLisp: > > > > I've got a coroutine that generates an infinite sequence of data. > > ... > > The upshot of this method is that I don't have to manually kill any of > the > > coroutines, they are all automatically garbage collected when I no longer > > use them. > > In PicoLisp, execution and garbage collection of coroutines are related > in this way: > > While a coroutine is running - *independent* from whether it is > referenced from anywhere else - it will not be garbage collected. > > Only if it finished execution (either by dropping off the end of its > code, by doing a 'throw' outside itself, or by being explicitly stopped > by another (co)routine), it will be garbage collected. Collected are > then all data which are referenced from the now freed stack segment. > > > > If I understand it correctly, creating a coroutine in PicoLisp creates > > a global symbol that keeps the reference to this coroutine > > This not correct. The coroutine does not create a symbol. It is the Lisp > *reader* which finds or creates a symbol 'myCoroutine' when reading an > expression like > > (co 'myCoroutine (...)) > > But this symbol is just a tag to access the coroutine. It is not > relevant for garbage collecting the coroutine itself. > > This symbol does not need to be global. You can use a transient symbol > > (co "myCoroutine" (...)) > > and thus have a file-local scope, or use a namespace. > > The transient symbol may go out of scope, but the coroutine continues to > exist until it terminates as described above. > > > > explicitly remove the coroutine when I no longer need it - it can never > get > > automatically garbage collected because it's linked to a global symbol. > > So you indeed need to call > > (co 'myCoroutine) > > if you are not sure if it did not already terminate by itself. But this > has nothing to do with the tag symbol. > > Let's clear up this in IRC :) > > ☺/ A!ex > > -- > UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe >
