Replace Symbols in AST with free-eable objects

[daveraja]

I would like to re-use clingo's parser as a fact parser in a process where the output won't necessary by passed directly to the solver. Unfortunate clingo's AST returns Symbol objects for its primitive data (string, constant, integer) and these objects currently cannot be freed ( issue #203 ).

So it might be a useful feature to separate the AST from the Symbol objects so that calling the parser only deals with free-able objects.

[rkaminsk]

Since we have #203 it would, be better to address this issue. Right now clingo internalizes any string it sees regardless of whether it is used in a symbol or not (typically logic programs involve many occurring constants). This memory is never freed. Also note that numbers do not allocate extra memory. Unfortunately, addressing the issue is quite involved. This has to be well planned and involves touching almost every file in the clingo implementation.

Now, it would certainly be possible to address your issue but I'ld rather do this right rather than patching on a few ends.

[daveraja]

Fair enough, I didn't have a sense of how difficult it would be. As you say better to address it once rather than in many places.