Module type Dalton_sig.ERROR_REPORT

module type ERROR_REPORT = sig  end

The implementation of the signature ERROR_REPORT given to the library allows customizing error messages printed when unification, resolution or comparison fail. A general purpose instance implementation is provided by Dalton_templates.ErrorReport.

Unification errors

val unification : Format.formatter ->
       term1:Dalton_aux.printing ->
       term2:Dalton_aux.printing -> explanation:Dalton_aux.printing -> unit

unification ppf ~term1 ~term2 ~explanation reports an unification failure of the terms term1 and term2. explanation gives a short explanation of the reason of the failure, generated itself by one of the functions cycle or incompatible.

val cycle : Format.formatter ->
       variable:Dalton_aux.printing -> term:Dalton_aux.printing -> unit

cycle ppf variable term prints the explanation of an unification failure due to the occur-check.

val incompatible : Format.formatter ->
       term1:Dalton_aux.printing -> term2:Dalton_aux.printing -> unit

cycle ppf ~term1 ~term2 prints the explanation of an unification failure due to incompatibles type constructors.

Constraints solving errors

val ldestr : Format.formatter -> term:Dalton_aux.printing -> unit

ldestr ppf ~term tells that the left-destructor has been applied on the type term term which cannot be so.

val rdestr : Format.formatter -> term:Dalton_aux.printing -> unit

rdestr ppf ~term tells that the right-destructor has been applied on the type term term which cannot be so.

val inequality : Format.formatter -> lb:Dalton_aux.printing -> ub:Dalton_aux.printing -> unit

inequality ppf ~lb ~ub tells that a constraint is not satisfiable because it implies the incorrect inequality lb < ub between constant bounds.

Schemes comparison

val incompatible_schemes : Format.formatter ->
       scheme1:Dalton_aux.printing ->
       scheme2:Dalton_aux.printing -> explanation:Dalton_aux.printing -> unit

incompatible_schemes ppf ~scheme1 ~scheme2 ~explanation reports that schemes scheme1 and scheme2 are not comparable, because of an unification error. explanation gives a short explanation of the reason of the failure, generated itself by one of the functions cycle or incompatible above.

val missing_desc : Format.formatter ->
       scheme:Dalton_aux.printing ->
       variable:Dalton_aux.printing -> term:Dalton_aux.printing -> unit

missing_desc ppf ~scheme ~variable ~term reports a comparison failure due to a variable instatiation.

val missing_constraint : Format.formatter ->
       scheme:Dalton_aux.printing -> constrain:Dalton_aux.printing -> unit

missing_desc ppf ~scheme ~variable ~term reports a comparison failure due to a missing inequality.

val missing_bound : Format.formatter ->
       scheme:Dalton_aux.printing ->
       constrain:Dalton_aux.printing ->
       explanation:Dalton_aux.printing option -> unit

missing_desc ppf ~scheme ~variable ~term reports a comparison failure due to a missing constant bound.

Minimal instance

val minimal : Format.formatter ->
       scheme:Dalton_aux.printing -> variables:Dalton_aux.printing -> unit

minimal ppf ~scheme ~variablesx prints a message telling that the type scheme scheme has no minimal instance. variables prints a list of the variables of the scheme which do not have a minimal solution.