filterANLid {xegaDerivationTrees}

Filter an Attributed Node List (ANL) of a derivation tree by a symbol identifier.

Description

filterANLid() deletes all nodes whose node$ID does not match node$ID. If the resulting list is empty, a list of length 0 is returned.

Usage

filterANLid(ANL, nodeID = 1)

Arguments

ANL

Attributed node list.

nodeID

Integer. The identifier of a symbol.

Details

An attributed node has the following elements:

• $ID: Id in the symbol table ST.

• $NT: Is the symbol a non-terminal?

• $Pos: Position in the trail.

• $Depth: Depth of node.

• $RDepth: Residual depth for expansion.

• $subtreedepth: Depth of subtree starting here.

• $Index: R index of the node in the derivation tree. Allows fast tree extraction and insertion.

For the implementation of crossover and mutation, we expect a non-terminal symbol identifier.

Value

An attributed node list with nodes whose depths are in minb:maxb. Each node is represented as a list of the following attributes:

• Node$ID: Id in the symbol table ST.

• Node$NT: Is the symbol a non-terminal?

• Node$Pos: Position in the trail.

• Node$Depth: Depth of node.

• Node$RDepth: Residual depth for expansion.

• Node$subtreedepth: Depth of subtree starting here.

• Node$Index: R index of the node in the derivation tree. Allows fast tree extraction and insertion.

See Also

Other Access Tree Parts: filterANL(), treeANL(), treeChildren(), treeRoot()

Examples

g<-compileBNF(booleanGrammar())
set.seed(111)
a<-randomDerivationTree(g$Start, g, maxdepth=10)
b<-treeANL(a, g$ST)
c<-filterANLid(b, nodeID=5)
d<-filterANLid(b, nodeID=6)
e<-filterANLid(b, nodeID=7)
f<-filterANLid(b, nodeID=8)