Safe Haskell	None
Language	Haskell2010

Database.Schema.Migrations.Dependencies

Description

This module types and functions for representing a dependency graph of arbitrary objects and functions for querying such graphs to get dependency and reverse dependency information.

Synopsis

class (Eq a, Ord a) => Dependable a where
- depsOf :: a -> [Text]
- depId :: a -> Text
data DependencyGraph a = DG {
- depGraphObjectMap :: [(a, Int)]
- depGraphNameMap :: [(Text, Int)]
- depGraph :: Gr Text Text
}
mkDepGraph :: Dependable a => [a] -> Either String (DependencyGraph a)
dependencies :: Dependable d => DependencyGraph d -> Text -> [Text]
reverseDependencies :: Dependable d => DependencyGraph d -> Text -> [Text]

Documentation

class (Eq a, Ord a) => Dependable a where Source #

Dependable objects supply a representation of their identifiers, and a list of other objects upon which they depend.

Methods

depsOf :: a -> [Text] Source #

The identifiers of the objects on which a depends.

depId :: a -> Text Source #

The identifier of a Dependable object.

Instances

Instances details

Dependable Migration Source #
Instance details Defined in Database.Schema.Migrations.Migration Methods depsOf :: Migration -> [Text] Source # depId :: Migration -> Text Source #

data DependencyGraph a Source #

A DependencyGraph represents a collection of objects together with a graph of their dependency relationships. This is intended to be used with instances of Dependable.

Constructors

DG
Fields depGraphObjectMap :: [(a, Int)] A mapping of `Dependable` objects to their graph vertex indices. depGraphNameMap :: [(Text, Int)] A mapping of `Dependable` object identifiers to their graph vertex indices. depGraph :: Gr Text Text A directed `Gr` (graph) of the `Dependable` objects' dependency relationships, with `Text` vertex and edge labels.

Instances

Instances details

Eq a => Eq (DependencyGraph a) Source #
Instance details Defined in Database.Schema.Migrations.Dependencies Methods (==) :: DependencyGraph a -> DependencyGraph a -> Bool # (/=) :: DependencyGraph a -> DependencyGraph a -> Bool #
Show a => Show (DependencyGraph a) Source #
Instance details Defined in Database.Schema.Migrations.Dependencies Methods showsPrec :: Int -> DependencyGraph a -> ShowS # show :: DependencyGraph a -> String # showList :: [DependencyGraph a] -> ShowS #

mkDepGraph :: Dependable a => [a] -> Either String (DependencyGraph a) Source #

Build a dependency graph from a list of Dependables. Return the graph on success or return an error message if the graph cannot be constructed (e.g., if the graph contains a cycle).

dependencies :: Dependable d => DependencyGraph d -> Text -> [Text] Source #

Given a dependency graph and an ID, return the IDs of objects that the object depends on. IDs are returned with least direct dependencies first (i.e., the apply order).

reverseDependencies :: Dependable d => DependencyGraph d -> Text -> [Text] Source #

Given a dependency graph and an ID, return the IDs of objects that depend on it. IDs are returned with least direct reverse dependencies first (i.e., the revert order).