[Issue 23361] std.uni.normalize should be pure

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23361

Imperatorn <johan_forsberg_86 at hotmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |johan_forsberg_86 at hotmail.c
                   |                            |om

--- Comment #1 from Imperatorn <johan_forsberg_86 at hotmail.com> ---
I took a look at this.

If you mark the following as pure:
normalize
decompose
decomposeHangul

Then there's only this that needs to be pure (in normalize)

() @trusted {
    decomposed.assumeSafeAppend();
    ccc.length = 0;
    ccc.assumeSafeAppend();
} ();

To cheat and not make the appenders pure but the block pure we can just add
pure:

() @trusted pure {
    decomposed.assumeSafeAppend();
    ccc.length = 0;
    ccc.assumeSafeAppend();
} ();

But, we still need some way there to allow calling the impure append from the
pure block.

Maybe we could cast some function pointer to pure, I don't know.

I tested wrapping it in a debug block and that makes it work, but I'm not sure
what the "real" solution would look like.

() @trusted pure {
    debug {
        decomposed.assumeSafeAppend();
        ccc.length = 0;
        ccc.assumeSafeAppend();
    }
} ();

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