lean2/tests/lean/unification_hints1.lean

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import data.list data.nat
open list nat
structure unification_constraint := {A : Type} (lhs : A) (rhs : A)
structure unification_hint := (pattern : unification_constraint) (constraints : list unification_constraint)
namespace toy
constants (A : Type.{1}) (f h : A → A) (x y z : A)
definition g [irreducible] (x y : A) : A := f z
#unify (g x y), (f z)
definition toy_hint [unify] (x y : A) : unification_hint :=
unification_hint.mk (unification_constraint.mk (g x y) (f z)) []
#unify (g x y), (f z)
print [unify]
end toy
namespace add
constants (n : )
#unify (n + 1), succ n
definition add_zero_hint [unify] (m n : ) [has_add ] [has_one ] [has_zero ] : unification_hint :=
unification_hint.mk (unification_constraint.mk (m + 1) (succ n)) [unification_constraint.mk m n]
#unify (n + 1), (succ n)
print [unify]
end add
namespace canonical
structure Canonical := (carrier : Type) (op : carrier → carrier)
attribute Canonical.carrier [irreducible]
constants (A : Type.{1}) (f : A → A) (x : A)
definition A_canonical : Canonical := Canonical.mk A f
#unify (Canonical.carrier A_canonical), A
definition Canonical_hint [unify] (C : Canonical) : unification_hint :=
unification_hint.mk (unification_constraint.mk (Canonical.carrier C) A) [unification_constraint.mk C A_canonical]
-- TODO(dhs): we mark carrier as irreducible and prove A_canonical explicitly to work around the fact that
-- the default_type_context does not recognize the elaborator metavariables as metavariables,
-- and so cannot perform the assignment.
#unify (Canonical.carrier A_canonical), A
print [unify]
end canonical
print [unify] canonical