OK, I think I made my mind about this now. Thanks for your comments. Well, after fighting one more time yesterday against things that were strings and that I expected to be symbols, I would really love to see them merged. The string / symbols distinction feels like an onion to me. As long as any string can be translated in one and only one symbol, and vice versa. That means case sensitivity, UTF-8 in symbols too, etc. Everything Arc already has.
I don't know if interning strings would really kill performance. Lua does it if I remember well, and it is quite performant. Anyway, mutable strings are a real performance killer, since you must compare them with scheme's 'equal? instead of 'eq?.
Now, you are right too, they don't represent exactly the same thing, so simply removing one of them would quite feel bad, but sometimes you have to make both worlds communicate. That's a matter of syntax too. After all, "Hello, Arc world" could be a special syntax meaning : the quotation of the symbol |Hello,\ Arc\ world|. A triple-quote syntax could be added, too.
It can be said the other way around : every time you need a string and are provided with a symbol (or the opposite), an automatic coercion could be performed.
Well, anyway, I'm just thinking loud since I am not here to design the language (and since its designers don't seem to appear very often anymore) :)
