Support .assert from DATALOG-TEXT

[aartaka]

Hi! I'm fairly new to Datalog, so take this with a grain of salt. I found DATALOG-TEXT standard and it seems to be mostly sane and conventional. Is there any reason it's not supported by Souffle?

.assert instruction in particular resembles Souffle's .decl, so it might be the easiest and single most impactful step towards DATALOG-TEXT support.

Other fun features to support:

• Aliases like <- and ⟵ for :-; |, OR, and ∨ for ;; and &, AND, ∧ for ,.
• Feature pragmas, like disjunction or negation, allowing one to clearer express program requirements.
• More types, like string, integer, decimal, and boolean.

[quentin]

Hi,
I'm sure Soufflé grammar was inspired by Prolog.

Soufflé was first released in 2016, years before DATALOG-TEXT spec. That at least explains why it could not be chosen as a standard when the original authors designed Soufflé language.

Personally it is the first time that I ear about DATALOG-TEXT. I would be curious to know if there are some datalog engines supporting it, and if the (small) datalog community was involved in the making of this spec.