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| -rw-r--r-- | lib/sublanguage.ml | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/sublanguage.ml b/lib/sublanguage.ml new file mode 100644 index 0000000..3df91f1 --- /dev/null +++ b/lib/sublanguage.ml @@ -0,0 +1,29 @@ +(** Effect classification for sublanguage operations. + + Categorically: + - Query: a natural transformation between instance functors (DRL). + Side-effect-free; the database state is unchanged. + - Transition: a morphism in the category of database states (DDL, + DML, ICL, DCL, and future TCL). Produces a new state via + substitution (Harper, PFPL ch. 3-4). + + Future sublanguages: + - TCL -> Transition (transaction boundaries are state morphisms + with atomicity constraints) + - PPL -> new effect class: potentially non-terminating computation + (Turing-complete; breaks the termination guarantee of DRL) + - ACL -> a functor restriction: narrows the admissible natural + transformations based on authorization context *) +type result = + | Query of Relation.t + | Transition of Management.Database.t * string + +module type S = sig + type storage + type ast + type error + val name : string + val parse_sexp : Sexplib.Sexp.t -> (ast, error) Result.t + val execute : storage -> Management.Database.t -> ast -> (result, error) Result.t + val sexp_of_error : error -> Sexplib.Sexp.t +end |