Re: Cannot Qualify Variadic Functions with Lazy Arguments as nothrow
On Thursday, 14 May 2015 at 10:18:13 UTC, Maxim Fomin wrote: On Thursday, 14 May 2015 at 09:53:20 UTC, Per Nordlöw wrote: At https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L43 I've implemented a function either() with behaviour similar to the `or` function/operator in dynamic languages such as Python and Lisp. I'm almost satisified with it except that the lazy evaluation at https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L45 cannot be made nothrow. If I qualify the function as nothrow DMD complains as algorithm_ex.d(45,16): Error: 'a' is not nothrow algorithm_ex.d(46,29): Error: '_param_1' is not nothrow I don't see a reason why any of these two cases should throw. Lazy argument is essentially delegate/function. Currently there is no way to mark it as nothrow. The same problem occurs if I make the implementation use only one function and check the recursion termination case with `static if (bs.length == 1)` instead. Is there a workaround for this? One way to address is to use delegate explicitly. int foo(lazy int a) //nothrow { return a; } int bar(int delegate() nothrow dg) nothrow { return dg(); } void main() nothrow { int a; bar(()=a); } That does not feel right at all. D's filosophy is to infer these things.Are you saying that I should create to overloads for the leaf case of either(), namely one that takes a nothrow delegate as argument and another overload that handles the throw case. Further you example functions are not templates. either() must be a template. Could you please show how to modify either() to use your delegate-version instead.
Re: Cannot Qualify Variadic Functions with Lazy Arguments as nothrow
On Thursday, 14 May 2015 at 09:53:20 UTC, Per Nordlöw wrote: I'm almost satisified with it except that the lazy evaluation at https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L45 cannot be made nothrow. If I qualify the function as nothrow DMD complains as algorithm_ex.d(45,16): Error: 'a' is not nothrow algorithm_ex.d(46,29): Error: '_param_1' is not nothrow https://issues.dlang.org/show_bug.cgi?id=12647
Cannot Qualify Variadic Functions with Lazy Arguments as nothrow
At https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L43 I've implemented a function either() with behaviour similar to the `or` function/operator in dynamic languages such as Python and Lisp. I'm almost satisified with it except that the lazy evaluation at https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L45 cannot be made nothrow. If I qualify the function as nothrow DMD complains as algorithm_ex.d(45,16): Error: 'a' is not nothrow algorithm_ex.d(46,29): Error: '_param_1' is not nothrow I don't see a reason why any of these two cases should throw. The same problem occurs if I make the implementation use only one function and check the recursion termination case with `static if (bs.length == 1)` instead. Is there a workaround for this?
Re: Cannot Qualify Variadic Functions with Lazy Arguments as nothrow
On Thursday, 14 May 2015 at 09:53:20 UTC, Per Nordlöw wrote: At https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L43 I've implemented a function either() with behaviour similar to the `or` function/operator in dynamic languages such as Python and Lisp. I'm almost satisified with it except that the lazy evaluation at https://github.com/nordlow/justd/blob/master/algorithm_ex.d#L45 cannot be made nothrow. If I qualify the function as nothrow DMD complains as algorithm_ex.d(45,16): Error: 'a' is not nothrow algorithm_ex.d(46,29): Error: '_param_1' is not nothrow I don't see a reason why any of these two cases should throw. Lazy argument is essentially delegate/function. Currently there is no way to mark it as nothrow. The same problem occurs if I make the implementation use only one function and check the recursion termination case with `static if (bs.length == 1)` instead. Is there a workaround for this? One way to address is to use delegate explicitly. int foo(lazy int a) //nothrow { return a; } int bar(int delegate() nothrow dg) nothrow { return dg(); } void main() nothrow { int a; bar(()=a); }