GenProg.GenExpr

An interface to genetically programmable expressions.

Documentation

class GenExpr e where

This typeclass defines an interface to expressions that can be genetically programmed. The operations that must be provided by instances of this class are used for the generation of random individuals as well as crossover and mutation operations. (An instance for members of the Data typeclass is provided in GenProg.GenExpr.Data.)

Minimal complete definition: exchange, nodeMapM, nodeMapQ, and nodeIndices.

Methods

exchange :: e -> Int -> e -> Int -> (e, e)

Exchanges subtrees of two expressions: exchange e1 n1 e2 n2 replaces the subexpression of e1 rooted in node n1 with the subexpression of e2 rooted in n2, and vice versa.

nodeMapM :: Monad m => (e -> m e) -> e -> m e

Maps a monadic transformation function over the immediate children of the given node.

nodeMapQ :: (e -> a) -> e -> [a]

Maps a query function over the immediate children of the given node and returns a list of results.

nodeIndices :: e -> ([Int], [Int])

A list of indices of internal (functional) and external (terminal) nodes of an expression.

adjustM :: Monad m => (e -> m e) -> e -> Int -> m e

Adjusts a subexpression rooted at the given node by applying a monadic transformation function.

nodes :: e -> Int

Number of nodes an expression has.

depth :: e -> Int

The depth of an expression. Equals 1 for single-node expressions.

Instances

Data a => GenExpr a