Postfix type notation - readability and parsing?

[Simen Kjærås]

On Tuesday, 5 March 2019 at 22:29:33 UTC, aliak wrote:
> 1) putting the variable name at the end makes it hard to see 
> and you'd need to scroll horizontally to get to see what this 
> type is for.
>
> 2) doing it like the above is confusing to see which name 
> belongs to which type because you're so used to a type 
> declaration being on one line.
>
> 3) Splitting it over multiple lines like:
>
> static immutable Option!(
>     ushort,
>     "p|port",
>     "Sets the port used for serving.",
>     "PORT",
>     8888
> ) port;
>
> 4) Deciding to go with a mixin approach so you can have the 
> variable name on the left and on the same line like:
>
> mixin Option!("port", ushort, "p|port",  "Sets the port used 
> for serving.", "PORT",  8888);
>
> 5) putting it on the right after an opAssign ala:
>
> auto port = Option!(...)


Just to add a 6) to the mix:

alias port = Option!(immutable ushort, "p|port", "Sets the port 
used for serving.", "PORT", 8888);

static this() {
     port = 1234;
}

template Option(T, string s, string s2, string s3, T 
defaultValue) {
     import std.traits : Unqual, CopyTypeQualifiers;
     struct Impl {
         Unqual!T _value;
         alias _value this;
         this(T t) {}
     }
     CopyTypeQualifiers!(T, Impl) Option;
}

// Also does the right thing in structs and classes:

struct S {
     static alias port = Option!(immutable ushort, "p|port", "Sets 
the port used for serving.", "PORT", 8888);
}

static this() {
     S.port = 1234;
}

--
   Simen