Module `Evd`

This file defines the pervasive unification state used everywhere in Coq tactic engine. It is very low-level and most of the functions exported here are irrelevant to the standard API user. Consider using Evarutil, Sigma or Proofview instead.

A unification state (of type evar_map) is primarily a finite mapping from existential variables to records containing the type of the evar (evar_concl), the context under which it was introduced (evar_hyps) and its definition (evar_body). evar_extra is used to add any other kind of information.

It also contains conversion constraints, debugging information and information about meta variables.

type econstr
type etypes = econstr

Existential variables and unification states

Evar filters

module Filter : sig ... end

module Abstraction : sig ... end

Evar infos

type evar_body = | Evar_empty | Evar_defined of econstr
type evar_info = { evar_concl : econstr; Type of the evar. evar_hyps : Environ.named_context_val; Context of the evar. evar_body : evar_body; Optional content of the evar. evar_filter : Filter.t; Boolean mask over evar_hyps. Should have the same length. When filtered out, the corresponding variable is not allowed to occur in the solution evar_abstract_arguments : Abstraction.t; Boolean information over evar_hyps, telling if an hypothesis instance can be imitated or should stay abstract in HO unification problems and inversion (see second_order_matching_with_args for its use). evar_source : Evar_kinds.t Loc.located; Information about the evar. evar_candidates : econstr list option; List of possible solutions when known that it is a finite list }

val make_evar : Environ.named_context_val -> etypes -> evar_info
val evar_concl : evar_info -> econstr
val evar_context : evar_info -> (econstr, etypes) Context.Named.pt
val evar_filtered_context : evar_info -> (econstr, etypes) Context.Named.pt
val evar_hyps : evar_info -> Environ.named_context_val
val evar_filtered_hyps : evar_info -> Environ.named_context_val
val evar_body : evar_info -> evar_body
val evar_candidates : evar_info -> Constr.constr list option
val evar_filter : evar_info -> Filter.t
val evar_env : evar_info -> Environ.env
val evar_filtered_env : evar_info -> Environ.env
val map_evar_body : (econstr -> econstr) -> evar_body -> evar_body
val map_evar_info : (econstr -> econstr) -> evar_info -> evar_info

Unification state

type evar_map: Type of unification state. Essentially a bunch of state-passing data needed to handle incremental term construction.

val empty : evar_map: The empty evar map.

val from_env : Environ.env -> evar_map: The empty evar map with given universe context, taking its initial universes from env.

val from_ctx : UState.t -> evar_map: The empty evar map with given universe context

val is_empty : evar_map -> bool: Whether an evarmap is empty.

val has_undefined : evar_map -> bool: has_undefined sigma is true if and only if there are uninstantiated evars in sigma.

val new_evar : evar_map -> ?⁠name:Names.Id.t -> ?⁠typeclass_candidate:bool -> evar_info -> evar_map * Evar.t: Creates a fresh evar mapping to the given information.

val add : evar_map -> Evar.t -> evar_info -> evar_map: add sigma ev info adds ev with evar info info in sigma. Precondition: ev must not preexist in sigma.

val find : evar_map -> Evar.t -> evar_info: Recover the data associated to an evar.

val find_undefined : evar_map -> Evar.t -> evar_info: Same as find but restricted to undefined evars. For efficiency reasons.

val remove : evar_map -> Evar.t -> evar_map: Remove an evar from an evar map. Use with caution.

val mem : evar_map -> Evar.t -> bool: Whether an evar is present in an evarmap.

val fold : (Evar.t -> evar_info -> 'a -> 'a) -> evar_map -> 'a -> 'a: Apply a function to all evars and their associated info in an evarmap.

val fold_undefined : (Evar.t -> evar_info -> 'a -> 'a) -> evar_map -> 'a -> 'a: Same as fold, but restricted to undefined evars. For efficiency reasons.

val raw_map : (Evar.t -> evar_info -> evar_info) -> evar_map -> evar_map: Apply the given function to all evars in the map. Beware: this function expects the argument function to preserve the kind of evar_body, i.e. it must send Evar_empty to Evar_empty and Evar_defined c to some Evar_defined c'.

val raw_map_undefined : (Evar.t -> evar_info -> evar_info) -> evar_map -> evar_map: Same as raw_map, but restricted to undefined evars. For efficiency reasons.

val define : Evar.t -> econstr -> evar_map -> evar_map

Set the body of an evar to the given constr. It is expected that:

The evar is already present in the evarmap.
The evar is not defined in the evarmap yet.
All the evars present in the constr should be present in the evar map.

val define_with_evar : Evar.t -> econstr -> evar_map -> evar_map: Same as define ev body evd, except the body must be an existential variable ev'. This additionally makes ev' inherit the obligation and typeclass flags of ev.

val cmap : (econstr -> econstr) -> evar_map -> evar_map: Map the function on all terms in the evar map.

val is_evar : evar_map -> Evar.t -> bool: Alias for mem.

val is_defined : evar_map -> Evar.t -> bool: Whether an evar is defined in an evarmap.

val is_undefined : evar_map -> Evar.t -> bool: Whether an evar is not defined in an evarmap.

val add_constraints : evar_map -> Univ.Constraint.t -> evar_map: Add universe constraints in an evar map.

val undefined_map : evar_map -> evar_info Evar.Map.t: Access the undefined evar mapping directly.

val drop_all_defined : evar_map -> evar_map
val is_maybe_typeclass_hook : (evar_map -> Constr.constr -> bool) Hook.t

Instantiating partial terms

exception NotInstantiatedEvar

val existential_value : evar_map -> econstr Constr.pexistential -> econstr: existential_value sigma ev raises NotInstantiatedEvar if ev has no body and Not_found if it does not exist in sigma

val existential_value0 : evar_map -> Constr.existential -> Constr.constr
val existential_type : evar_map -> econstr Constr.pexistential -> etypes
val existential_type0 : evar_map -> Constr.existential -> Constr.types
val existential_opt_value : evar_map -> econstr Constr.pexistential -> econstr option: Same as existential_value but returns an option instead of raising an exception.

val existential_opt_value0 : evar_map -> Constr.existential -> Constr.constr option
val evar_instance_array : (Constr.named_declaration -> 'a -> bool) -> evar_info -> 'a array -> (Names.Id.t * 'a) list
val instantiate_evar_array : evar_info -> econstr -> econstr array -> econstr
val evars_reset_evd : ?⁠with_conv_pbs:bool -> ?⁠with_univs:bool -> evar_map -> evar_map -> evar_map: spiwack: this function seems to somewhat break the abstraction.

Misc

val restrict : Evar.t -> Filter.t -> ?⁠candidates:econstr list -> ?⁠src:Evar_kinds.t Loc.located -> evar_map -> evar_map * Evar.t: Restrict an undefined evar into a new evar by filtering context and possibly limiting the instances to a set of candidates (candidates are filtered according to the filter)

val is_restricted_evar : evar_map -> Evar.t -> Evar.t option: Tell if an evar comes from restriction of another evar, and if yes, which

val set_typeclass_evars : evar_map -> Evar.Set.t -> evar_map

Mark the given set of evars as available for resolution.

Precondition: they should indeed refer to undefined typeclass evars.

val get_typeclass_evars : evar_map -> Evar.Set.t: The set of undefined typeclass evars

val is_typeclass_evar : evar_map -> Evar.t -> bool: Is the evar declared resolvable for typeclass resolution

val get_obligation_evars : evar_map -> Evar.Set.t: The set of obligation evars

val set_obligation_evar : evar_map -> Evar.t -> evar_map: Declare an evar as an obligation

val is_obligation_evar : evar_map -> Evar.t -> bool: Is the evar declared as an obligation

val downcast : Evar.t -> etypes -> evar_map -> evar_map: Change the type of an undefined evar to a new type assumed to be a subtype of its current type; subtyping must be ensured by caller

val evar_source : Evar.t -> evar_map -> Evar_kinds.t Loc.located: Convenience function. Wrapper around find to recover the source of an evar in a given evar map.

val evar_ident : Evar.t -> evar_map -> Names.Id.t option
val rename : Evar.t -> Names.Id.t -> evar_map -> evar_map
val evar_key : Names.Id.t -> evar_map -> Evar.t
val evar_source_of_meta : Constr.metavariable -> evar_map -> Evar_kinds.t Loc.located
val dependent_evar_ident : Evar.t -> evar_map -> Names.Id.t

Side-effects

val emit_side_effects : Safe_typing.private_constants -> evar_map -> evar_map: Push a side-effect into the evar map.

val eval_side_effects : evar_map -> Safe_typing.private_constants: Return the effects contained in the evar map.

val drop_side_effects : evar_map -> evar_map: This should not be used. For hacking purposes.

Future goals

type goal_kind = | ToShelve | ToGiveUp

val declare_future_goal : ?⁠tag:goal_kind -> Evar.t -> evar_map -> evar_map: Adds an existential variable to the list of future goals. For internal uses only.

val declare_principal_goal : ?⁠tag:goal_kind -> Evar.t -> evar_map -> evar_map: Adds an existential variable to the list of future goals and make it principal. Only one existential variable can be made principal, an error is raised otherwise. For internal uses only.

val future_goals : evar_map -> Evar.t list: Retrieves the list of future goals. Used by the refine primitive of the tactic engine.

val principal_future_goal : evar_map -> Evar.t option: Retrieves the name of the principal existential variable if there is one. Used by the refine primitive of the tactic engine.

type future_goals

val save_future_goals : evar_map -> future_goals: Retrieves the list of future goals including the principal future goal. Used by the refine primitive of the tactic engine.

val reset_future_goals : evar_map -> evar_map: Clears the list of future goals (as well as the principal future goal). Used by the refine primitive of the tactic engine.

val restore_future_goals : evar_map -> future_goals -> evar_map: Sets the future goals (including the principal future goal) to a previous value. Intended to be used after a local list of future goals has been consumed. Used by the refine primitive of the tactic engine.

val fold_future_goals : (evar_map -> Evar.t -> evar_map) -> evar_map -> future_goals -> evar_map: Fold future goals

val map_filter_future_goals : (Evar.t -> Evar.t option) -> future_goals -> future_goals: Applies a function on the future goals

val filter_future_goals : (Evar.t -> bool) -> future_goals -> future_goals: Applies a filter on the future goals

val dispatch_future_goals : future_goals -> Evar.t list * Evar.t list * Evar.t list * Evar.t option: Returns the future_goals dispatched into regular, shelved, given_up goals; last argument is the goal tagged as principal if any

val extract_given_up_future_goals : future_goals -> Evar.t list * Evar.t list: An ad hoc variant for Proof.proof; not for general use

val shelve_on_future_goals : Evar.t list -> future_goals -> future_goals: Push goals on the shelve of future goals

Sort variables

Evar maps also keep track of the universe constraints defined at a given point. This section defines the relevant manipulation functions.

exception UniversesDiffer

val add_universe_constraints : evar_map -> UnivProblem.Set.t -> evar_map

Add the given universe unification constraints to the evar map.

raises UniversesDiffer: in case a first-order unification fails.

raises UniverseInconsistency: .

Extra data

Evar maps can contain arbitrary data, allowing to use an extensible state. As evar maps are theoretically used in a strict state-passing style, such additional data should be passed along transparently. Some old and bug-prone code tends to drop them nonetheless, so you should keep cautious.

module Store : Store.S: Datatype used to store additional information in evar maps.

val get_extra_data : evar_map -> Store.t
val set_extra_data : Store.t -> evar_map -> evar_map

Enriching with evar maps

type 'a sigma = { it : 'a; The base object. sigma : evar_map; The added unification state. }: The type constructor 'a sigma adds an evar map to an object of type 'a.

val sig_it : 'a sigma -> 'a
val sig_sig : 'a sigma -> evar_map
val on_sig : 'a sigma -> (evar_map -> evar_map * 'b) -> 'a sigma * 'b

The state monad with state an evar map

module MonadR : Monad.S with type +'a t = evar_map -> evar_map * 'a

module Monad : Monad.S with type +'a t = evar_map -> 'a * evar_map

Meta machinery

These functions are almost deprecated. They were used before the introduction of the full-fledged evar calculus. In an ideal world, they should be removed. Alas, some parts of the code still use them. Do not use in newly-written code.

module Metaset : Util.Set.S with type S.elt = Constr.metavariable

module Metamap : Util.Map.ExtS with type key = Constr.metavariable and module Set := Metaset

type 'a freelisted = { rebus : 'a; freemetas : Metaset.t; }

val metavars_of : econstr -> Metaset.t
val mk_freelisted : econstr -> econstr freelisted
val map_fl : ('a -> 'b) -> 'a freelisted -> 'b freelisted

type instance_constraint = | IsSuperType | IsSubType | Conv

val eq_instance_constraint : instance_constraint -> instance_constraint -> bool

type instance_typing_status = | CoerceToType | TypeNotProcessed | TypeProcessed

type instance_status = instance_constraint * instance_typing_status

type clbinding = | Cltyp of Names.Name.t * econstr freelisted | Clval of Names.Name.t * econstr freelisted * instance_status * econstr freelisted
type conv_pb = Reduction.conv_pb: Unification constraints

type evar_constraint = conv_pb * Environ.env * econstr * econstr

val add_conv_pb : ?⁠tail:bool -> evar_constraint -> evar_map -> evar_map: The following two functions are for internal use only, see Evarutil.add_unification_pb for a safe interface.

val conv_pbs : evar_map -> evar_constraint list
val extract_changed_conv_pbs : evar_map -> (Evar.Set.t -> evar_constraint -> bool) -> evar_map * evar_constraint list
val extract_all_conv_pbs : evar_map -> evar_map * evar_constraint list
val loc_of_conv_pb : evar_map -> evar_constraint -> Loc.t option

val evars_of_term : Constr.constr -> Evar.Set.t: including evars in instances of evars

val evars_of_named_context : (econstr, etypes) Context.Named.pt -> Evar.Set.t
val evars_of_filtered_evar_info : evar_info -> Evar.Set.t
val meta_list : evar_map -> (Constr.metavariable * clbinding) list: Metas

val meta_defined : evar_map -> Constr.metavariable -> bool
val meta_value : evar_map -> Constr.metavariable -> econstr: meta_fvalue raises Not_found if meta not in map or Anomaly if meta has no value

val meta_fvalue : evar_map -> Constr.metavariable -> econstr freelisted * instance_status
val meta_opt_fvalue : evar_map -> Constr.metavariable -> (econstr freelisted * instance_status) option
val meta_type : evar_map -> Constr.metavariable -> etypes
val meta_type0 : evar_map -> Constr.metavariable -> Constr.types
val meta_ftype : evar_map -> Constr.metavariable -> etypes freelisted
val meta_name : evar_map -> Constr.metavariable -> Names.Name.t
val meta_declare : Constr.metavariable -> etypes -> ?⁠name:Names.Name.t -> evar_map -> evar_map
val meta_assign : Constr.metavariable -> (econstr * instance_status) -> evar_map -> evar_map
val meta_reassign : Constr.metavariable -> (econstr * instance_status) -> evar_map -> evar_map
val clear_metas : evar_map -> evar_map
val meta_merge : ?⁠with_univs:bool -> evar_map -> evar_map -> evar_map: meta_merge evd1 evd2 returns evd2 extended with the metas of evd1

val undefined_metas : evar_map -> Constr.metavariable list
val map_metas_fvalue : (econstr -> econstr) -> evar_map -> evar_map
val map_metas : (econstr -> econstr) -> evar_map -> evar_map

type metabinding = Constr.metavariable * econstr * instance_status

val retract_coercible_metas : evar_map -> metabinding list * evar_map

FIXME: Nothing to do here

type rigid = UState.rigid = | UnivRigid | UnivFlexible of bool Is substitution by an algebraic ok?

val univ_rigid : rigid
val univ_flexible : rigid
val univ_flexible_alg : rigid

type 'a in_evar_universe_context = 'a * UState.t

val restrict_universe_context : evar_map -> Univ.LSet.t -> evar_map
val universe_of_name : evar_map -> Names.Id.t -> Univ.Level.t: Raises Not_found if not a name for a universe in this map.

val universe_binders : evar_map -> UnivNames.universe_binders
val new_univ_level_variable : ?⁠loc:Loc.t -> ?⁠name:Names.Id.t -> rigid -> evar_map -> evar_map * Univ.Level.t
val new_univ_variable : ?⁠loc:Loc.t -> ?⁠name:Names.Id.t -> rigid -> evar_map -> evar_map * Univ.Universe.t
val new_sort_variable : ?⁠loc:Loc.t -> ?⁠name:Names.Id.t -> rigid -> evar_map -> evar_map * Sorts.t
val add_global_univ : evar_map -> Univ.Level.t -> evar_map
val universe_rigidity : evar_map -> Univ.Level.t -> rigid
val make_flexible_variable : evar_map -> algebraic:bool -> Univ.Level.t -> evar_map: See UState.make_flexible_variable

val make_nonalgebraic_variable : evar_map -> Univ.Level.t -> evar_map: See UState.make_nonalgebraic_variable.

val is_sort_variable : evar_map -> Sorts.t -> Univ.Level.t option: is_sort_variable evm s returns Some u or None if s is not a local sort variable declared in evm

val is_flexible_level : evar_map -> Univ.Level.t -> bool
val normalize_universe : evar_map -> Univ.Universe.t -> Univ.Universe.t
val normalize_universe_instance : evar_map -> Univ.Instance.t -> Univ.Instance.t
val set_leq_sort : Environ.env -> evar_map -> Sorts.t -> Sorts.t -> evar_map
val set_eq_sort : Environ.env -> evar_map -> Sorts.t -> Sorts.t -> evar_map
val set_eq_level : evar_map -> Univ.Level.t -> Univ.Level.t -> evar_map
val set_leq_level : evar_map -> Univ.Level.t -> Univ.Level.t -> evar_map
val set_eq_instances : ?⁠flex:bool -> evar_map -> Univ.Instance.t -> Univ.Instance.t -> evar_map
val check_eq : evar_map -> Univ.Universe.t -> Univ.Universe.t -> bool
val check_leq : evar_map -> Univ.Universe.t -> Univ.Universe.t -> bool
val check_constraints : evar_map -> Univ.Constraint.t -> bool
val evar_universe_context : evar_map -> UState.t
val universe_context_set : evar_map -> Univ.ContextSet.t
val universe_subst : evar_map -> UnivSubst.universe_opt_subst
val universes : evar_map -> UGraph.t
val to_universe_context : evar_map -> Univ.UContext.t: to_universe_context evm extracts the local universes and constraints of evm and orders the universes the same as Univ.ContextSet.to_context.

val univ_entry : poly:bool -> evar_map -> Entries.universes_entry
val const_univ_entry : poly:bool -> evar_map -> Entries.universes_entry
val check_univ_decl : poly:bool -> evar_map -> UState.universe_decl -> Entries.universes_entry
val merge_universe_context : evar_map -> UState.t -> evar_map
val set_universe_context : evar_map -> UState.t -> evar_map
val merge_context_set : ?⁠loc:Loc.t -> ?⁠sideff:bool -> rigid -> evar_map -> Univ.ContextSet.t -> evar_map
val merge_universe_subst : evar_map -> UnivSubst.universe_opt_subst -> evar_map
val with_context_set : ?⁠loc:Loc.t -> rigid -> evar_map -> 'a Univ.in_universe_context_set -> evar_map * 'a
val nf_univ_variables : evar_map -> evar_map * Univ.universe_subst
val fix_undefined_variables : evar_map -> evar_map
val refresh_undefined_universes : evar_map -> evar_map * Univ.universe_level_subst
val minimize_universes : evar_map -> evar_map: Universe minimization

val update_sigma_env : evar_map -> Environ.env -> evar_map

val fresh_sort_in_family : ?⁠loc:Loc.t -> ?⁠rigid:rigid -> evar_map -> Sorts.family -> evar_map * Sorts.t
val fresh_constant_instance : ?⁠loc:Loc.t -> Environ.env -> evar_map -> Names.Constant.t -> evar_map * Constr.pconstant
val fresh_inductive_instance : ?⁠loc:Loc.t -> Environ.env -> evar_map -> Names.inductive -> evar_map * Constr.pinductive
val fresh_constructor_instance : ?⁠loc:Loc.t -> Environ.env -> evar_map -> Names.constructor -> evar_map * Constr.pconstructor
val fresh_global : ?⁠loc:Loc.t -> ?⁠rigid:rigid -> ?⁠names:Univ.Instance.t -> Environ.env -> evar_map -> Names.GlobRef.t -> evar_map * econstr

type open_constr = evar_map * econstr

type unsolvability_explanation = | SeveralInstancesFound of int Failure explanation.

Summary names

val evar_counter_summary_tag : int Summary.Dyn.tag
val create_evar_defs : evar_map -> evar_map: Deprecated functions

module MiniEConstr : sig ... end: Use this module only to bootstrap EConstr

`evar_concl : econstr;`	Type of the evar.
`evar_hyps : Environ.named_context_val;`	Context of the evar.
`evar_body : evar_body;`	Optional content of the evar.
`evar_filter : Filter.t;`	Boolean mask over `evar_hyps`. Should have the same length. When filtered out, the corresponding variable is not allowed to occur in the solution
`evar_abstract_arguments : Abstraction.t;`	Boolean information over `evar_hyps`, telling if an hypothesis instance can be imitated or should stay abstract in HO unification problems and inversion (see `second_order_matching_with_args` for its use).
`evar_source : Evar_kinds.t Loc.located;`	Information about the evar.
`evar_candidates : econstr list option;`	List of possible solutions when known that it is a finite list

`it : 'a;`	The base object.
`sigma : evar_map;`	The added unification state.

`\|` `UnivRigid`
`\|` `UnivFlexible of bool`	Is substitution by an algebraic ok?

Deprecated functions