I would like to define non-line-termination-character = <any character other than %x000D / %x000A> in lexer.mll. I have tried let non_line_termination_character = [^('\x0D' '\x0A')], but it gave me a syntax error.
I think let non_line_termination_character = [^'\x0D'] intersect [^'\x0A'] would work, but I don't know how to express intersect.
Could anyone help?
PS: The rule is at 12.2.4 Regular expressions of : http://caml.inria.fr/pub/docs/manual-ocaml/manual026.html
The syntax of a character set in ocamllex doesn't allow parentheses. The following works for me:
let non_line_termination_character = [^ '\x0d' '\x0a' ]
There's no general operator for intersecting regular expressions in ocamllex. But for two character sets a and b you can write a # (a # b).
let nona = [^ 'a']
let nonb = [^ 'b']
let nonab = nona # (nona # nonb)
(Weirdly, my tests show this works for every character set I try, except it fails for your specific example of non-CR and non-LF. It actually seems like a bug. But maybe I'm missing something obvious.)
The set described by [^'\x0D'] includes '\x0A' and vice-versa, so the union of the two sets includes everything. I think this is what you were trying for:
[^'\x0D' '\x0A']
