On Saturday, 27 April 2024 at 14:58:19 UTC, IchorDev wrote:

/*-->*/ const /*<--*/ int myvalue = switch(code) {
    // ...
};

const string myValue = (){
	switch(code){
		case 1:    return "what";
		case 2, 3: return "ok";
		default:   return "no";
	}
}();

Besides the problems exposed in the first answer (essentially: "it's a workaround") I've found a case where this does not work. It's about selecting an lvalue with a switch:

void main()
{
    int a,b,c,d,cond;

    auto ref () {
        switch (cond)
        {
            case 1: return a;
            case 2: return b;
            case 3: return c;
            default: return d;
        }
    }() = 0;
}

see https://issues.dlang.org/show_bug.cgi?id=24525

The switchexp would have the same problem: the parser sees "switch" then it branches on statement parsing. Statement parsing sees "switch", then it branches on SwitchStmt parsing.

Not so dramatic but the lambda solution is 1. a workaround, 2. not perfect.
For that case you have 1. to explain the lambda trick 2. why you have to put the lambda between parens.

With the switch expr, you just have to explain point 2.

On Tuesday, 30 April 2024 at 13:15:45 UTC, Basile B. wrote:

There's now a fix for that.

That's why the syntax should be designed to be easily distinguishable by the parser.