logtk

Core types and algorithms for logic
IN THIS PACKAGE
Module Logtk . HO_unif

Higher-Order Unification

type term = Term.t
type penalty = int

penalty on the search space

val enum_prop : ?mode:[ `Full | `Pragmatic | `Neg | `None | `TF ] -> Term.var Scoped.t -> enum_cache:Term.Set.t ref -> offset:int -> (Subst.t * penalty) list

Given a variable of type τ1…τn -> prop, enumerate possible shapes for it

  • parameter v

    the variable to refine + its scope. Must return prop.

  • parameter offset

    to create fresh variables (should be unused elsewhere)

  • parameter mode

    if `Neg, only tries negation; `None, do nothing; otherwise do all connectives

type pair = Type.t list * term * term

unification pair

val pp_pair : pair CCFormat.printer
val unif_pairs : ?fuel:int -> pair list Scoped.t -> offset:int -> (pair list * Unif_subst.t * penalty * Subst.Renaming.t) list

unif_pairs pairs ~scope_new_vars returns a list of (partial) solutions to the HO unification problem pairs. Each solution is a list of remaining constraints (with the substitution already applied), a substitution, some penalty to influence the search space, and a renaming used for the substitution

val default_fuel : int ref

Default amount of fuel for unif_pairs

val enable_norm_subst : bool ref

If true, substitutions obtained with unif_pairs are normalized and β-reduced