| Maintainer | bastiaan.heeren@ou.nl |
|---|---|
| Stability | provisional |
| Portability | portable (depends on ghc) |
| Safe Haskell | None |
| Language | Haskell98 |
Ideas.Common.Id
Description
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
IsIdfor constructing identifiers - Type class
HasIdfor 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
Identifyfor 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.
- data Id
- class IsId a where
- (#) :: (IsId a, IsId b) => a -> b -> Id
- class HasId a where
- unqualified :: HasId a => a -> String
- qualifiers :: HasId a => a -> [String]
- qualification :: HasId a => a -> String
- describe :: HasId a => String -> a -> a
- description :: HasId a => a -> String
- showId :: HasId a => a -> String
- compareId :: HasId a => a -> a -> Ordering
- class HasId a => Identify a where
- module Data.Monoid
Constructing identifiers
Abstract data type for identifiers with a hierarchical name, carrying a description. The data type provides a fast comparison implementation.
Type class IsId for constructing identifiers. Examples are
newId "algebra.equation", newId ("a", "b", "c"), and newId ()
for the empty identifier.
Minimal complete definition
(#) :: (IsId a, IsId b) => a -> b -> Id infixr 8 Source
Appends two identifiers. Both parameters are overloaded.
Accessing (and changing) identifiers
Type classfor accessing (and changing) the identifier of an entity.
Instances
| HasId Id | |
| HasId ViewPackage | |
| HasId Symbol | |
| HasId Binding | |
| HasId Service | |
| HasId DomainReasoner | |
| HasId (Ref a) | |
| HasId (RewriteRule a) | |
| HasId (Rule a) | |
| HasId (Step a) | |
| 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 Source
Get the unqualified part of the identifier (i.e., last string).
qualifiers :: HasId a => a -> [String] Source
Get the list of qualifiers of the identifier (i.e., everything but the last string).
qualification :: HasId a => a -> String Source
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 Source
Give a description for the current entity. If there already is a description, both strings are combined.
description :: HasId a => a -> String Source
Get the current description.
compareId :: HasId a => a -> a -> Ordering Source
Compare two identifiers based on their names. Use compare for a fast
ordering based on hash values.
Labeling with identifiers
module Data.Monoid