digitalmars.D.bugs - [Issue 24523] New: writeln doesn't memoize its templates
- d-bugmail puremagic.com (71/71) Apr 26 https://issues.dlang.org/show_bug.cgi?id=24523
https://issues.dlang.org/show_bug.cgi?id=24523 Issue ID: 24523 Summary: writeln doesn't memoize its templates Product: D Version: D2 Hardware: x86_64 OS: Linux Status: NEW Severity: normal Priority: P1 Component: phobos Assignee: nobody puremagic.com Reporter: crazymonkyyy gmail.com copy and pasted from the open d discord some messages: ---- as far as I understand, writeln is a variadic template, so for each set of arguments you get a new instance of writeln in object code -- I would expect a trivail optiomization here with how templates auto memoize -- on practice, this generates a lot of garbage code https://godbolt.org/z/9Gx6ja5vo void main() { import std.stdio : writeln; writeln("hello"); writeln(123); writeln(123, 456); } -- it dups the template argument list 3 times -- ... why isnt writeln writen in such a way to auto memoize simplier write calls its one line of code difference -- wat? -- ```d void writeln(S...)(S args) { write(args, '\n'); } ``` given grims code, write(int,int,string) and write(int,string) are both being compiled when it chould be ```d void writeln(T...)(T args){ static foreach(a;args){write(a);} write("\n"); } ``` and only compile write(int) and write(string) --- I can't believe it, but monkyyy is actually correct on this one https://godbolt.org/z/edf46vcqv import std.stdio; void smartWriteln(T...)(T args) { static foreach(a; args) { write(a);} write("\n"); } void a() { writeln(123, 345, 789); smartWriteln(123, 345, 789); } --- etc. writeln should be cleaned up and made to memoize arguments --
Apr 26