Yeah, that's a bug. I haven't yet bothered to create a version of read without the infix transform. For now you have to:
'(5 (+) 5)
If you decide to try to fix this I'd love to hear your experiences. The point of wart was to be easy to hack on, but I'm losing steam because it's been hard to get feedback on that score.
I'm going to have to familiarize myself with the internals before I actually try to fix it. After looking for a little bit, I think the issue is in the transform_infix function where it handles the quoting.
if (is_quote_or_unquote(n.elems.front())) {
list<ast_node>::iterator p = n.elems.begin();
while (is_quote_or_unquote(*p)) {
trace("infix") << "skipping past " << *p;
++p;
if (p == n.elems.end()) {
trace("infix") << "just quotes/unquotes " << n;
return n;
}
}
I would think that after you determine that the first element is a quote, you would just ignore the rest instead of going through and checking which ones are also quoted. Since I'm not that familiar with c++ or how the internals of wart work, I'm going to have to leave it to you to see if this is actually the problem.
Thanks for the investigation! Yes, that would be the way to disable transforms inside a quoted s-expr.
But I think that still would leave issues. For one, it is approximately as likely that a list innocuously contains a literal '+ as that we're constructing a fragment of code that is eventually intended to be eval'd. We need a way to say, "this is code" or "this is never going to be eval'd." A second issue is that quoting isn't the only way to read data. Imagine using read to read a list from a file. How would we suppress infix there?
I actually think reading data from a file is the bigger issue. Small quoted lists in code will be noticed, and can be replaced with some (klunky) combination of list and cons. It's far worse if you have a multi-megabyte file that silently gets corrupted because of one character.
