incomplete printing of char predicates

[Sven Verdoolaege]

barrel$ cat typ.idp vocabulary V { A(char) } structure S : V { } theory T : V { A("a"). } barrel$ ~/local/install/idp/bin/runidp.sh -e 'stdoptions.nbmodels=2;L=modelexpand(T,S);for i=1,#L do print (L[i]) end;' typ.idp structure : V { A[std::char] = { 0; 1; 2; 3; 4; 5; 6; 7; 8; 9; structure : V { A[std::char] = { 0; 1; 2; 3; 4; 5; 6; 7; 8; 9;

I'm not sure how many elements should be in the predicate in those two structures, but I would expect at least "a" to be one of them. The printing seems to break off prematurely.

[Bart Bogaerts]

Lua cuts of our string after encoutering the NULL character \0, the successor of '9'. We should fix this by

• Either restricting our chars
• Print an empty char instead of the escape character \0

[Broes De Cat]

Or drop char?

[Broes De Cat]

Also, after rewriting the rest of the printing, chars are now printed with " " instead of single quotes, which might be incorrect?