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author | Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net> | 2017-11-09 17:27:58 +0100 |
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committer | Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net> | 2018-02-10 01:34:19 +0100 |
commit | 35fba70509d9fb219b2a88f8e7bd246b2671b39b (patch) | |
tree | 21cdb9aa905ef8f6375aa6cd119254794233d0ac /engine | |
parent | 10d3d803e6b57024dd15df7d61670ce42260948a (diff) |
Simplification: cumulativity information is variance information.
Since cumulativity of an inductive type is the universe constraints
which make a term convertible with its universe-renamed copy, the only
constraints we can get are between a universe and its copy.
As such we do not need to be able to represent arbitrary constraints
between universes and copied universes in a double-sized ucontext,
instead we can just keep around an array describing whether a bound
universe is covariant, invariant or irrelevant (CIC has no
contravariant conversion rule).
Printing is fairly obtuse and should be improved: when we print the
CumulativityInfo we add marks to the universes of the instance: = for
invariant, + for covariant and * for irrelevant. ie
Record Foo@{i j k} := { foo : Type@{i} -> Type@{j} }.
Print Foo.
gives
Cumulative Record Foo : Type@{max(i+1, j+1)} := Build_Foo
{ foo : Type@{i} -> Type@{j} }
(* =i +j *k |= *)
Diffstat (limited to 'engine')
-rw-r--r-- | engine/universes.ml | 11 | ||||
-rw-r--r-- | engine/universes.mli | 6 |
2 files changed, 0 insertions, 17 deletions
diff --git a/engine/universes.ml b/engine/universes.ml index eaddf98a8..3a00f0fd1 100644 --- a/engine/universes.ml +++ b/engine/universes.ml @@ -1103,14 +1103,3 @@ let solve_constraints_system levels level_bounds level_min = done; done; v - - -(** Operations for universe_info_ind *) - -(** Given a universe context representing constraints of an inductive - this function produces a UInfoInd.t that with the trivial subtyping relation. *) -let univ_inf_ind_from_universe_context univcst = - let freshunivs = Instance.of_array - (Array.map (fun _ -> new_univ_level ()) - (Instance.to_array (UContext.instance univcst))) - in CumulativityInfo.from_universe_context univcst freshunivs diff --git a/engine/universes.mli b/engine/universes.mli index 130dcf8bb..cb6e2ba1b 100644 --- a/engine/universes.mli +++ b/engine/universes.mli @@ -221,9 +221,3 @@ val pr_universe_opt_subst : universe_opt_subst -> Pp.t val solve_constraints_system : Universe.t option array -> Universe.t array -> Universe.t array -> Universe.t array - -(** Operations for universe_info_ind *) - -(** Given a universe context representing constraints of an inductive - this function produces a UInfoInd.t that with the trivial subtyping relation. *) -val univ_inf_ind_from_universe_context : UContext.t -> CumulativityInfo.t |