This replaces all user-defined variable names with continuously numbered
ones so that they don’t lead to syntax problems in ASP, while still
unique and distinguishable. For instance, this avoids problems when
variable names contain hyphens, which are allowed in PDDL identifiers
but not in ASP variables.
Previously, variables referenced within values were unpacked within
values. This was inconsistent, because all predicates are usually used
in their unpacked form in the rest of the output format. This commit
makes this consistent by using variables in their packed form within
values, making it more compact to handle them.
Patrick Lühne