Do you think if statement as expression would be nice to have in D?

[user1234]

On Saturday, 4 June 2022 at 20:11:09 UTC, user1234 wrote:
> On Saturday, 4 June 2022 at 16:55:37 UTC, user1234 wrote:
>> On Saturday, 4 June 2022 at 16:28:07 UTC, Nick Treleaven wrote:
>>> On Saturday, 4 June 2022 at 16:24:10 UTC, user1234 wrote:
>>>> On Saturday, 4 June 2022 at 16:15:26 UTC, Nick Treleaven 
>>>> wrote:
>>>>> On Saturday, 4 June 2022 at 11:35:41 UTC, user1234 wrote:
>>>>>> ```
>>>>>> const char = if (current < input.len)
>>>>>>             input[current]
>>>>>>         else
>>>>>>             break;
>>>>>> ```
>>>>>>
>>>>>> - So the `break` expression has a type ? And this type is 
>>>>>> compatible with the typê of `input[current]` ? wut ?
>>>>>
>>>>> Just like `throw` is an expression in D now. It's type is 
>>>>> noreturn, which implicitly converts to any type.
>>>>
>>>> I think this does not give intuitively what char value will 
>>>> be: undefined, 0 ?
>>>> Well in this case a loop is exited and char is out of scope 
>>>> so that does not matter but what if char is a var owned by 
>>>> the loop outer scope.
>>>
>>> In that case, no assignment would occur. Control flow was 
>>> interrupted before the assignment.
>>
>> yes, this is what I observe
>>
>> ```
>> const std = @import("std");
>>
>> pub fn ert(input: []const u8) u8 {
>>     var ret: u8 = 0;
>>     var current: usize = 0;
>>     while (true) {
>>         ret = if (current < input.len - 1)
>>             input[current]
>>         else
>>             break;
>>         current += 1;
>>     }
>>     return ret;
>> }
>>
>> pub fn main() void {
>>   const t : u8 = ert("ABC");
>>   std.debug.print("{}\n", .{t});
>> }
>> ```
>>
>>> 66
>>
>> I had no idea. Not mind changing however.
>
> So actually there's not even something like a common type 
> involved. The "then" part is used as assign rhs and the "else" 
> part is just unrelated.
>
> well "Okay" let's say ;) What a strange language tho.

imagine using a switch as assign lhs too:

     ```
         int a,b,c;
         switch (cond)
         {
             case 0: a; break;
             case 1: b; break;
             default: c;
         } = 0;
     ```

that whole thing of mixing expressions and statements looks 
really absurd even if there are special cases that may appear 
appealing.

In this last example you'd have to check that every case yields a 
compatible lvalue.
So this bring the fact that statements also have a value category 
!

Now maybe you also want chained assignments.

     ```
         int nope, a,b,c;
         nope = switch (cond)
         {
             case 0: a; break;
             case 1: b; break;
             default: c;
         } = 0;
     ```

No way.