Destructors, const structs, and opEquals

[Michel Fortin]

On 2010-12-10 17:12:16 -0500, Don <nospam at nospam.com> said:

> Steven Schveighoffer wrote:
>> To summarize for those looking for the C++ behavior, the equivalent would be:
>> 
>> void foo(auto ref const Widget)
> 
> That use of 'auto' is an abomination.

One problem I'm starting to realize is that we now have so many 
available qualifiers for function parameters than it's really easy to 
get lost.

In D1 it was simple: "in" for regular arguments (the default), 
"inout"/"ref" for passing arguments by refrence, and "out" for output 
arguments. They all had clear semantics and not too much overlap.

In D2, we've lost this simplicity. Add "const/immutable/shared", add 
"scope", change "in" as an alias for "const scope", give "inout" a 
totally new meaning, keep "ref" and "out" the same except that now 
"ref" can be prefixed with "auto" to give it a double meaning...  
choosing the right modifiers for function parameters is getting extra 
complicated.

Have we lost track of one of D's principles, that doing the right thing 
should be the easiest way to do things? To me it looks like we're 
adding more and more ways to pass arguments because the defaults are 
failing us. Perhaps it's time to revisit how arguments are passed by 
default.

As for "auto ref", if we're to keep it I think it'd be much better if 
it was a keyword of its own, such as "autoref". Having modifiers is one 
thing, but having modifiers that apply to modifiers is getting a little 
hard to parse in my head. This is not unprecedented, in English when 
one qualifier apply to another and it becomes hard to read we group 
them by adding a hyphen between the two.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/