On 06/08/2010 08:45 AM, Steven Schveighoffer wrote:
On Tue, 08 Jun 2010 07:23:39 -0400, Bernard Helyer <[email protected]>
wrote:

So I'm writing a compiler, and I wanted to create a list of TokenTypes
(an enum) and check to see if the current token is among them.
'A-ha!', says I, 'I'll use std.algorithm!' (as I hadn't tried it
really, yet, except for playing around)
So I look it up, and find 'find'. It returns an iterated range, or an
empty range on failure. A little funky, but that's okay, I can swing it!

immutable TokenType[] someList = [TokenType.Foo, TokenType.Bar];

...

while (find(someList, tokenStream.peek.type) != []) {
doStuff();
}

If I have unittests on, this assert is triggered:

static assert(is(typeof(s) == Tuple!(string, float)));

I didn't at first, so I got another error. So I looked closer at the
documentation, and it turns out it needs an input range, and that
needs popFront! Well, it can't popFront an immutable range, so I
dropped immutable, and decided to let convention and TLS sort the rest
out!

This should be filed as a bug. find should be able to strip the
immutable part from the array length itself since immutable T[]
implicitly casts to immutable(T)[]. I think this should be special cased.

For custom ranges, it's not as easy, but array should be supported as
well as is possible.

I agree. Someone please file this so it doesn't fall through the cracks.

Andrei

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