Scryer-prolog: Hexadecimal escape sequences sometimes cannot be parsed

[triska]

For example:

?- Cs = "\x2124\".
caught: error(syntax_error(cannot_parse_big_int),read_term/2:0)

Expected: Cs = "ℤ"..

This arose in the discussion of #459. I am filing this as its own issue since it can be tackled independently. This may be an interesting issue for new contributors.

[matt2xu]

I think this is in prolog_parser, I should be able to implement that relatively easily!

[triska]

I would greatly appreciate it, thank you a lot!

[triska]

This is even more important since such escape sequences already appear in answers, for example:

?- atom_codes(A, [8484]).
   A = '\x2124\'.

Currently, this cannot be pasted back.

[matt2xu]

PR opened on prolog_parser! https://github.com/mthom/prolog_parser/pull/8

[triska]

This is awesome, thank you a lot!