Re: taskPool.reduce vs algorithm.reduce
On Wednesday, 11 July 2018 at 10:07:33 UTC, Timoses wrote: On Wednesday, 11 July 2018 at 08:31:30 UTC, Dorian Haglund wrote: [...] As the error message says taskPool.reduce is a non-global template. It's embedded in a taskPool struct. I can't say what the reason is that a delegate cannot be used with such a template. I'd be interested in hearing what the reason is. (See Paul's reply). I'm trying to trick around it, but can't get this to work... https://run.dlang.io/is/EGbtuq You can make it all global: https://run.dlang.io/is/Kf8CLC From my own experience: Use only parallel foreach and save yourself a lot of hassle. That just works.
Re: taskPool.reduce vs algorithm.reduce
On Wednesday, 11 July 2018 at 08:31:30 UTC, Dorian Haglund wrote: Hi. I'm trying to use taskPool.reduce with a delegate, for example: import std.parallelism; int main(string[] args) { int f(int a, int b) { if (args.length > 1) return a+b; else return a-b; } auto res = taskPool.reduce!f([1, 2, 3]); return 0; } But it fails to compile (with gdc 8.1.0, dmd v2.081) complaining that template instance reduce!(f) cannot use local 'f' as parameter to non-global template reduce(functions...) The snippet above compiles with the reduce function from std.algorithm. Is there a way to make the code compile with taskPool.reduce ? (I don't want to write two functions and choosing one depending on args.length) Why the interface difference between std.algorithm's reduce and taskPool.reduce ? Best regards, Dorian As the error message says taskPool.reduce is a non-global template. It's embedded in a taskPool struct. I can't say what the reason is that a delegate cannot be used with such a template. I'd be interested in hearing what the reason is. (See Paul's reply). I'm trying to trick around it, but can't get this to work... https://run.dlang.io/is/EGbtuq import std.parallelism; int main(string[] args) { static int f(bool cond)(int a, int b) { static if (cond) return a+b; else return a-b; } template getF(alias func) { auto getF(T)(T arg) { if (args.length > 1) return func!(f!true)(arg); // line 18 else return func!(f!false)(arg); // line 20 } } auto res = getF!(taskPool.reduce)([1,2,3]); return 0; } onlineapp.d(18): Error: need this for reduce of type @system int(int[] _param_0) onlineapp.d(20): Error: need this for reduce of type @system int(int[] _param_0)
Re: taskPool.reduce vs algorithm.reduce
On Wednesday, 11 July 2018 at 08:31:30 UTC, Dorian Haglund wrote: But it fails to compile (with gdc 8.1.0, dmd v2.081) complaining that template instance reduce!(f) cannot use local 'f' as parameter to non-global template reduce(functions...) Congratulations! You've just run into issue 5710 [1], one of D's most annoying known bugs. [1]: https://issues.dlang.org/show_bug.cgi?id=5710 The snippet above compiles with the reduce function from std.algorithm. [...] Why the interface difference between std.algorithm's reduce and taskPool.reduce ? std.algorithm.reduce is a free function, so it can accept delegates as template parameters. taskPool.reduce is a member function, so it can't.
taskPool.reduce vs algorithm.reduce
Hi. I'm trying to use taskPool.reduce with a delegate, for example: import std.parallelism; int main(string[] args) { int f(int a, int b) { if (args.length > 1) return a+b; else return a-b; } auto res = taskPool.reduce!f([1, 2, 3]); return 0; } But it fails to compile (with gdc 8.1.0, dmd v2.081) complaining that template instance reduce!(f) cannot use local 'f' as parameter to non-global template reduce(functions...) The snippet above compiles with the reduce function from std.algorithm. Is there a way to make the code compile with taskPool.reduce ? (I don't want to write two functions and choosing one depending on args.length) Why the interface difference between std.algorithm's reduce and taskPool.reduce ? Best regards, Dorian