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| author |  Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net> | 2017-11-09 17:27:58 +0100 |
|---|---|---|
| committer | Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net> | 2018-02-10 01:34:19 +0100 |
| commit | 35fba70509d9fb219b2a88f8e7bd246b2671b39b (patch) | |
| tree | 21cdb9aa905ef8f6375aa6cd119254794233d0ac /checker/values.ml | |
| 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 'checker/values.ml')
| -rw-r--r-- | checker/values.ml | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/checker/values.ml b/checker/values.ml index 313067cb6..55e1cdb6f 100644 --- a/checker/values.ml +++ b/checker/values.ml @@ -110,10 +110,12 @@ let v_cstrs = (v_tuple "univ_constraint" [|v_level;v_enum "order_request" 3;v_level|])) +let v_variance = v_enum "variance" 3 + let v_instance = Annot ("instance", Array v_level) let v_context = v_tuple "universe_context" [|v_instance;v_cstrs|] let v_abs_context = v_context (* only for clarity *) -let v_abs_cum_info = v_tuple "cumulativity_info" [|v_abs_context; v_context|] +let v_abs_cum_info = v_tuple "cumulativity_info" [|v_abs_context; Array v_variance|] let v_context_set = v_tuple "universe_context_set" [|v_hset v_level;v_cstrs|] (** kernel/term *) |