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Groups > comp.lang.c++ > #81883
| From | Tim Rentsch <tr.17687@z991.linuxsc.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: "C++20 Coroutines" by Martin Bond |
| Date | 2021-10-06 13:19 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <865yu9rjnj.fsf@linuxsc.com> (permalink) |
| References | (3 earlier) <sieejh$1am$1@gioia.aioe.org> <siesre$171$1@gioia.aioe.org> <sihb4s$1s8m$1@gioia.aioe.org> <siktq3$vpc$4@dont-email.me> <87zgs1yby6.fsf@bsb.me.uk> |
Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
> Bonita Montero <Bonita.Montero@gmail.com> writes:
>
>> State-machines are _always_ spahgetti-code (while( !end )
>> switch( state ) { ... }), even when you write them conventionally.
>
> Obviously one person's spaghetti is another person's farfalle, but
> in my opinion, if the state is a (a pointer to a) function that
> returns (a pointer to) the next state, then you just get a clean
> loop calling a function:
>
> data d = { ... };
> State state = initial;
> while (state) state = (State)state(&d);
>
> C++ has trouble writing the recursive type, so you need a cast, but
> its a safe cast.
In C++, needing a cast can be avoided by wrapping the function
pointer in a class or struct, as for example:
class State {
typedef State (*Go)( data & );
Go go;
public:
State( Go g ) : go( g ) {}
operator bool(){ return go; }
State operator()( data &data ){
return go( data );
}
};
void
run_state_machine( State initial, data &data ){
State s = initial;
while( s ) s = s( data );
}
The example above is specific to a partcular type of "data" being
acted on, but it's easy to generalize around that shortcoming by
using templates.
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"C++20 Coroutines" by Martin Bond Lynn McGuire <lynnmcguire5@gmail.com> - 2021-09-20 16:30 -0500
Re: "C++20 Coroutines" by Martin Bond Bo Persson <bo@bo-persson.se> - 2021-09-21 09:28 +0200
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-21 11:45 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-21 15:37 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-21 17:40 +0200
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-22 05:22 +0000
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-22 09:26 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-22 16:40 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-22 15:01 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-23 05:38 +0200
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-23 09:05 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-24 18:15 +0200
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 00:57 +0000
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-23 09:11 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-24 18:17 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 09:19 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 12:00 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 10:09 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 12:18 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 10:39 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 12:42 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 10:44 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 13:14 +0200
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 12:44 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 15:58 +0200
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 13:59 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 16:23 +0200
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-28 07:24 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 15:28 +0000
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 15:04 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-25 18:44 +0200
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-26 14:15 +0000
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 12:32 +0000
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-23 07:42 +0000
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-23 09:14 +0000
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-24 04:42 +0000
Re: "C++20 Coroutines" by Martin Bond Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-24 18:19 +0200
Re: "C++20 Coroutines" by Martin Bond Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-09-24 21:07 +0100
Re: "C++20 Coroutines" by Martin Bond Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-06 13:19 -0700
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 00:58 +0000
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-27 05:39 +0000
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-29 02:30 +0000
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 09:20 +0000
Re: "C++20 Coroutines" by Martin Bond "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-22 11:31 +0200
Re: "C++20 Coroutines" by Martin Bond Sam <sam@email-scan.com> - 2021-09-22 18:43 -0400
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-23 07:45 +0000
Re: "C++20 Coroutines" by Martin Bond "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-09-23 01:53 -0700
Re: "C++20 Coroutines" by Martin Bond Sam <sam@email-scan.com> - 2021-09-24 19:21 -0400
Re: "C++20 Coroutines" by Martin Bond HorseyWorsey@the_stables.com - 2021-09-25 09:28 +0000
Re: "C++20 Coroutines" by Martin Bond Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-09-25 12:38 +0000
Re: "C++20 Coroutines" by Martin Bond Juha Nieminen <nospam@thanks.invalid> - 2021-09-27 05:42 +0000
Re: "C++20 Coroutines" by Martin Bond "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-25 15:14 +0200
Re: "C++20 Coroutines" by Martin Bond Manfred <noname@add.invalid> - 2021-09-25 23:07 +0200
Re: "C++20 Coroutines" by Martin Bond "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-26 01:50 +0200
Re: "C++20 Coroutines" by Martin Bond Manfred <noname@add.invalid> - 2021-09-26 19:12 +0200
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