Hey all,
I have been going over the new web interface in Guile 2.0, making sure
that it's OK for long-term use, and got myself into a quandary about
when to use strings and when to use symbols in an interface. I don't
pretend to have the right answer here, but this is the answer that I
have come to.
Let's say you have an association list. It could be (("foo" . "bar")) or
((foo . "bar")) or ((foo bar)), or even (("foo" . bar)). If you're
parsing this data from over the network, in textual form, which do you
use?
The answer is this:
* Use symbols when you want to match against a symbol literal in your
source code.
* Use strings otherwise.
* Don't worry about symbol-interning attacks, where the remote side
fills up your symbol table -- symbols are properly garbage-collected
in Guile 2.0.
So in this case, the answer is ((foo . "bar")) if you would ever do
(assoc-ref alist 'foo) in code, and (("foo" . "bar")) otherwise.
Cheers,
Andy
ps. I very, very rarely hold Python up as an example of language design,
especially regarding strings, but I think that their approach to string
mutabililty and identity is preferable to the symbol vs string
distinction that Scheme has.
--
http://wingolog.org/
