On Wednesday, 15 March 2017 at 17:27:35 UTC, ag0aep6g wrote:
Phobos has it: std.meta.aliasSeqOf "converts an input range
[...] to an
alias sequence." [1]
Woops, forgot to give the URL for that "[1]". Here it is:
http://dlang.org/phobos/std_meta.html#aliasSeqOf
Hello, I have a similar problem. For the life of me I can't make
CTFE work while manipulating collections. Source:
import std.meta;
import std.traits;
template isFunctionField(OwnerType, string field_name)
{
enum isFunctionField =
isFunction(mixin(OwnerType.stringof ~ "." ~ field_name));
}
string[] sfilter(T)(string[] fields)
{
string[] result;
foreach (f; fields)
{
enum isfunc = isFunctionField!(T, f);
// variable f cannot be read at compile time.
// Even when I change isFunctionField from template to function
that returns
// bool and takes "string field_name".
if (isfunc)
result ~= f;
}
return result;
}
string[] TypeFields(T)() pure
{
enum field_names = [__traits(allMembers, T)];
pragma(msg, typeof(field_names)); // prints string[]
pragma(msg, field_names); // prints correct member names
enum filtered = sfilter!(T)(field_names);
return filtered;
}
//then I call it by:
enum fields = TypeFields!(SomeStruct)();
I can get string array of class members allright. Whenever I
try to do any logic with it, I fail. I get that "enum field_names
= " is not lvalue. How should I pass it to sfilter? When I change
foreach loop into for loop, I can't index "string[] fields" array
since "variable fields cannot be read at compile time".
Should I pass field_names string array as some other type,
AliasSeq or something?
The thing is, on some level inside TypeFields, I will need to
mutate array, I can't stick to tuples. I tried declaring array
parameters immutable, but CTFE forbids casting from mutable into
immutable. I'm kinda out of ideas.
