rdf 1.0.0 · OCaml Package

Computing values in Sparql, mapping to/from RDF terms.

A value can be an error, and propagated in computations.

type error =

| Type_error of value * string
(*
The value has not the given expected "type"
*)
| Invalid_literal of Term.literal
(*
Invalid literal: bad integer string for an integer, ...
*)
| Exception of exn
(*
To keep the original exception which resulted in an error.
*)

and value =

| Err of error
(*
Value is an error
*)
| Blank of string
(*
A blank node with its label
*)
| Iri of Iri.t
(*
An IRI.
*)
| String of string
(*
A string literal.
*)
| Int of int * Iri.t
(*
An integer and the original datatype IRI
*)
| Float of float
(*
A decimal, float or double.
*)
| Bool of bool
(*
A Boolean.
*)
| HexBinary of string
(*
Binary data in hexadecimal, in lowercase
*)
| Datetime of Term.datetime
(*
A datetime.
*)
| Ltrl of string * string option
(*
A literal string with an optional language tag.
*)
| Ltrdt of string * Iri.t
(*
A literal value with a specified datatype.
*)

exception Error of error

val error : error -> 'a

Raise a Error exception with the given error.

val string_of_value : value -> string

Return a string to show the given value.

module ValueOrdered : sig ... end

module VMap : Map.S with type key = value

Maps over values.

module VSet : Set.S with type elt = value

Sets of values.

val string_of_error : error -> string

Return a human-readable message from the given error.

val iri : Iri.t -> value -> value

iri base v returns a Iri value, ensure the given value is an IRI. If it is a literal string, convert it to an IRI, eventually appending to the base IRI if the string expresses a relative IRI.

val datatype : value -> value

datatype v returns the IRI of the datatype of the value. If v is Err, Blank or Iri, return Err.

val string_literal : value -> string * string option

string_literal v returns a pair (string, optional language tag) if v is String of Ltrl. Else return Err.

val string : value -> value

string v returns a String value, converting any value to a string, except Err and Blank for which Err is returned.

val int : value -> value

int v returns a Int value, trying to convert literal values to an integer. Return Err if v is Err, Blank or Iri, or if the literal value could not be converted to an integer. Floats are truncated.

val float : value -> value

Same as int but for floats.

val bool : value -> value

Same as int but for booleans. Bool true, String "true", String "1", Int n with n<>0 and Float f when f is not nan nor zero evaluate to Bool true. Bool false, String "false", String "0", Int 0 and Float f when f is nan or zero evaluate to Bool false. Any other value evaluates to Err.

val datetime : value -> value

datetime v returns a Datetime, if possible. String literals are converted if possible; else Err is returned.

val ltrl : value -> value

Same as string, but languge tag is kept is present (i.e. if the value is a Ltrl).

val numeric : value -> value

Try to convert the given value to an Int or else to a Float, if the value is not already Int or Float.

val of_literal : Term.literal -> value

of_literal lit returns a value from a literal term.

val of_term : Term.term -> value

of_term term returns a value from an RDF term.

val to_term : value -> Term.term

to_term v converts the given value to an RDF term. If v is Error e, then exception e is raised.

package rdf