GraphRewriting.Rule
Description
Rewrite rules are represented as nested monads: a Rule is a Pattern that returns a Rewrite the latter directly defining the transformation of the graph. The Rewrite itself is expected to return a list of newly created nodes.
For rule construction a few functions a provided: The most basic one is rewrite. But in most cases erase, rewire, and 'replace*' should be more convenient. These functions express rewrites that replace the matched nodes of the Pattern, which comes quite close to the L -> R form in which graph rewriting rules are usually expressed.
- type Rule n = Pattern n (Rewrite n [Node])
- rewrite :: (Match -> Rewrite n [Node]) -> Rule n
- erase :: View [Port] n => Rule n
- rewire :: View [Port] n => [[Edge]] -> Rule n
- data RHS v
- replace :: (View [Port] n, View v n) => Int -> ([Edge] -> [RHS v]) -> Rule n
- (>>>) :: Rule n -> Rule n -> Rule n
- exhaustive :: Rule n -> Rule n
- everywhere :: Rule n -> Rule n
- apply :: Rule n -> Rewrite n [Node]
Documentation
rewrite :: (Match -> Rewrite n [Node]) -> Rule nSource
primitive rule construction with the matched nodes of the left hand side as a parameter
erase :: View [Port] n => Rule nSource
constructs a rule that deletes all of the matched nodes from the graph
rewire :: View [Port] n => [[Edge]] -> Rule nSource
Constructs a rule from a list of rewirings. Each rewiring specifies a list of hyperedges that are to be merged into a single hyperedge. All matched nodes of the left-hand side are removed.
replace :: (View [Port] n, View v n) => Int -> ([Edge] -> [RHS v]) -> Rule nSource
Constructs a rule that replaces the matched nodes of the left-hand side by new nodes and rewirings. It generates an amount of new edges specified by the Int. In most cases the functions below named replace* should be sufficient.
(>>>) :: Rule n -> Rule n -> Rule nSource
Replaces the matched nodes by a list of new nodes and rewirings.
Replaces the matched nodes by a list of new nodes and rewirings. It also generates one new edge.
Replaces the matched nodes by a list of new nodes and rewirings. It also generates two new edges.
You get the idea.
Apply two rules consecutively. Second rule is only applied if first one succeeds. Fails if (and only if) first rule fails.
exhaustive :: Rule n -> Rule nSource
Apply a rule repeatedly as long as it is applicable. Fails if rule cannot be applied at all.
everywhere :: Rule n -> Rule nSource
Apply a rule to all current redexes one by one. Neither new redexes or destroyed redexes are reduced.