DIP9 -- Redo toString API

[Steven Schveighoffer]

On Tue, 07 Dec 2010 11:44:56 -0500, Bruno Medeiros  
<brunodomedeiros+spam at com.gmail> wrote:

> On 02/12/2010 21:08, Steven Schveighoffer wrote:
>> On Thu, 02 Dec 2010 11:31:49 -0500, Bruno Medeiros
>> <brunodomedeiros+spam at com.gmail> wrote:
>>
>>> On 21/11/2010 17:21, Don wrote:
>>>
>>> That idea is quite idiotic indeed, no question about it. However, that
>>> is not toString() 's idea! The point of toString (at least across
>>> languages, not D specifically) is to provide a *default*
>>> representation of a type.
>>>
>>> It doesn't preclude other representations, and if format&friends
>>> (writef, etc.), don't provide an integrated way to create/write a
>>> string using custom formats for a given object/struct, that is
>>> format's problem, it is not toString's fault.
>>
>> to!string(x) will handle what toString does now.
>>
>
> So? What was the point here, I didn't get it.

The point is, we don't need a toString method *and* a formatted output  
method.  The toString method is replaced by the formatted output method in  
the proposal (writeTo), which already contains a format specifier.

>
>>> In fact, I think that coding only a default toString for a type may be
>>> more common than otherwise (coding a toString that actually uses the
>>> format specifiers). The string based format specifier is just not that
>>> common outside of numerical types.
>>
>> You can ignore the format specifier if you want to.
>>
>> -Steve
>
> For calling toString, yes, you can ignore it. But as for defining the  
> toString method, not entirely, you still have to write the format  
> parameter (", string format = null"). After that it won't hinder you in  
> any way, it will just be unnecessary visual baggage.

Yes, that is my point.

> So the downside of having to write that extra parameter is incredibly  
> low, it is merely aesthetic (plus the initial one-off impact of people  
> learning what the format parameter is for).
> However, toString is a core part of the language, and a very common to  
> define, and if D were to gain more mainstream usage, I worry that  
> something like 98% (or something like that) of all toStrings would not  
> use format, so it seems like a bit of a waste.
>
> It is not an issue I care that much about, only a little bit.

In the proposal, toString is removed, only writeTo would exist (which has  
formatting support).  I guess I don't really understand what you are  
asking for.  I interpreted your posts as requests that we don't  
change/deprecate toString, is that not the case?

-Steve