Hi,
I just took a look into commonly used functionality of Phobos.
Such as getting the string representation of a enum.
the following code:
import std.conv;
enum ET
{
One,
Two
}
static assert(to!string(ET.One) == "One");
takes about 220 milliseconds to compile.
creating a 7.5k object file
Using my -vcg-ast it becomes visible that it expands to ~17000
lines of template-instantiations.
explaining both the compilation time and the size.
Compiling the following code:
string enumToString(E)(E v)
{
static assert(is(E == enum), "emumToString is only meant for
enums");
mixin ({
string result = "final switch(v) {\n";
foreach(m;[__traits(allMembers, E)])
{
result ~= "\tcase E." ~ m ~ " :\n"
~ "\t\treturn \"" ~ m ~ "\";\n"
~ "\tbreak;\n";
}
return result ~ "}";
} ());
}
private enum ET
{
One,
Two
}
static assert (enumToString(ET.One) == "One");
takes about 4 milliseconds to compile.
creating a 4.8k object file.
Granted this version will result in undefined behavior if you
pass something like (cast(ET) 3) to it.
But the 55x increase in compilation speed is well worth it :)
