>> 3. The new stuff can have completely different parsing rules to 
>> Haskell. (Presumably the Lisp, Forth and Erlang methods can't do that.)
> 
> Erlang, no, because it's already parsed when you get it. FORTH and LISP, 
> yes, it's exactly the point of it.  If you can read arbitrary amount of 
> input off the input file as you're compiling, you can pretty much 
> completely change the parsing rules.

The way you said "take each token and pass it through a macro" made it 
sound like the input stream gets tokenised first - which means if what 
you want to quote has different ideas about what constitutes a "token", 
you've got a problem.

>> If you could write XML tags literally, then an expression like "if x<y 
>> then if y>z then..." would suddenly parse as an XML tag, which would 
>> be a Very Bad Thing. Really, having to explicitly say you're doing 
>> weird stuff isn't so bad.
> 
> Yeah, that was just an example I saw. Obviously you'd have to take care. 
> I haven't used Erlang enough to understand the subtleties of its 
> mechanisms.

Square enuf.

-- 
http://blog.orphi.me.uk/
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