Ideas.Common.Id

Many entities of the Ideas framework carry an Id for identification. Identifiers have a hierarchical structure of an arbitrary depth (e.g. algebra.equation or a.b.c). Valid symbols for identifiers are the alpha-numerical characters, together with - and _. Each identifier carries a description and a hash value for fast comparison.

Functionality for identifiers is provided by means of three type classes:

• Type class IsId for constructing identifiers
• Type class HasId for accessing (and changing) the identifier of an entity. Instances of this type class must always have exactly one identifier (although this identifier can be empty).
• Type class Identify for labeling entities with an identifier. Instances of this type class typically allow labels to appear at multiple locations within their structure.

The Id datatype implements and re-exports the Monoid interface.

Constructing identifiers

data Id

Abstract data type for identifiers with a hierarchical name, carrying a description. The data type provides a fast comparison implementation.

Instances

Eq Id

Data Id

Ord Id

Read Id

Show Id

Arbitrary Id

Monoid Id

HasId Id

IsId Id

class IsId a where

Type class IsId for constructing identifiers. Examples are newId "algebra.equation", newId ("a", "b", "c"), and newId () for the empty identifier.

Minimal complete definition

newId

Methods

newId :: a -> Id

concatId :: [a] -> Id

Instances

IsId Char

IsId ()

IsId Id

IsId a => IsId [a]

IsId a => IsId (Maybe a)

(IsId a, IsId b) => IsId (Either a b)

(IsId a, IsId b) => IsId (a, b)

(IsId a, IsId b, IsId c) => IsId (a, b, c)

(#) :: (IsId a, IsId b) => a -> b -> Id infixr 8

Appends two identifiers. Both parameters are overloaded.

Accessing (and changing) identifiers

class HasId a where

Type classfor accessing (and changing) the identifier of an entity.

Methods

getId :: a -> Id

changeId :: (Id -> Id) -> a -> a

Instances

HasId Id

HasId ViewPackage

HasId Symbol

HasId Binding

HasId Service

HasId DomainReasoner

HasId (Ref a)

HasId (RewriteRule a)

HasId (Rule a)

HasId (Decl f)

HasId (LabeledStrategy a)

HasId (Predicate a)

HasId (Exercise a)

HasId (State a)

(HasId a, HasId b) => HasId (Either a b)

HasId (Isomorphism a b)

HasId (View a b)

unqualified :: HasId a => a -> String

Get the unqualified part of the identifier (i.e., last string).

qualifiers :: HasId a => a -> [String]

Get the list of qualifiers of the identifier (i.e., everything but the last string).

qualification :: HasId a => a -> String

Get the qualified part of the identifier. If the identifier consists of more than one part, the parts are separated by a period (.).

describe :: HasId a => String -> a -> a

Give a description for the current entity. If there already is a description, both strings are combined.

description :: HasId a => a -> String

Get the current description.

showId :: HasId a => a -> String

Show the identifier.

compareId :: HasId a => a -> a -> Ordering

Compare two identifiers based on their names. Use compare for a fast ordering based on hash values.

Labeling with identifiers

class HasId a => Identify a where

Type class for labeling entities with an identifier

Methods

(@>) :: IsId n => n -> a -> a

Instances

Identify (Predicate a)

Identify (Isomorphism a b)

Identify (View a b)

module Data.Monoid