On Sunday, 18 March 2018 at 11:29:47 UTC, Joe wrote:
On Monday, 12 March 2018 at 03:50:42 UTC, Joe wrote:
On Monday, 12 March 2018 at 03:13:08 UTC, Seb wrote:
Out of interest: I wonder what's your usecase for using qsort. Or in other words: why you can't use the high-level std.algorithm.sorting.sort?

This is only temporary. I will be using std.algorithm.sorting.sort. I was converting a C program and it annoyed me that I couldn't get the qsort invocation past the D compiler.

Now that I'm trying to use std.algorithm.sorting, I'm again puzzled by what I need to use for the "less" predicate. My first try was:

sort!((a, b) => to!string((*a).name) < to!string((*b).name))(recs);

This results in the error:

Error: template std.algorithm.sorting.sort cannot deduce function from argument types !((a, b) => to!string((*a).name) < to!string((*b).name))(Record*[10]),

This basically says you have fixed size array, in D they don’t decay to slices/pointers for safety reasons (it’s stack memory that is easy to leak out of scope with disasterous consequences).

Do this to get the usual ptr + length:

sort!((a, b) => to!string((*a).name) < to!string((*b).name))(recs[]);

Also to!string would be computed on each compare anew. May want to use schwartzSort to avoid that, on 10 elements there is no real difference though.

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