I've discovered that the 'log' function as well several similar
functions are only defined as taking a real argument and
returning a real, unlike most other std.math functions, which
have triple definitions (also supporting double and float types).
This created a problem when I tried compiling code like the
following:
---
import std.math;
alias double function(double) Funcptr;
Funcptr sinptr = &sin;
Funcptr tanptr = &tan;
Funcptr logptr = &log;
---
dmd (and ldc2) report
test.d(7): Error: cannot implicitly convert expression & log of
type real function(real x) pure nothrow @nogc @safe to double
function(double)
[ldc2 also reports
test.d(6): Error: cannot implicitly convert expression & tan of
type real function(real x) pure nothrow @nogc @trusted to double
function(double)
but apparently this is an LDC-only problem]
I'd like to know if the lack of double/float versions of 'log',
'log10', etc. are intentional, i.e., there's some rationale
behind it, or an oversight. I'd also like to know the
proper/best way to deal with the error, considering the real code
embeds the 'Funcptr's in an array of structs. Is it better to
write a function 'mylog' that internally casts the argument and
the return value, or is there some safe way to cast away the
'log' function at the point of initializing the array?
Also, is it preferable to post the first question
(intentional/oversight) in the Phobos forum? And what is the
preferred way of reporting the LDC problem, via GitHub?
