declareTuple function
Declares a tuple with the given name and sorts, the fields of the
tuple are named name$0, name$1, etc.
Implementation
TupleInfo declareTuple(String name, Iterable<Sort> sorts) =>
currentContext.declareTuple(
Sym(name),
{
for (var i = 0; i < sorts.length; i++)
Sym('$name\$$i'): sorts.elementAt(i),
},
);