addE                    Add an edge or a list of edges to the data
                        frame for edges.
addV                    Add a vertex to the data frame for vertices.
booleanGrammar          A constant function which returns the BNF
                        (Backus-Naur Form) of a context-free grammar
                        for the XOR problem.
chooseNode              Randomly selects an attributed node in an
                        attributed node list.
chooseRule              Selects a production rule index at random from
                        a vector of production rules.
chooseRulek             Selects k-th production rule index from a
                        vector of production rules.
compatibleSubtrees      Test the compatibility of subtrees.
compileBNF              Compile a BNF (Backus-Naur Form) of a
                        context-free grammar.
decodeAndFixDT          Decodes (and completes) a derivation tree into
                        a working program.
decodeCDT               Converts a complete derivation tree into a
                        program.
decodeDT                Decodes a derivation tree into a program.
decodeDTsym             Decodes a derivation tree into a list of the
                        leaf symbols of the derivation tree.
decodeSymVec            Decodes a vector of symbols.
decodeTree              Returns a list of all symbols of a derivation
                        tree in depth-first left-to-right order.
filterANL               Filter an Attributed Node List (ANL) of a
                        derivation tree by depth.
filterANLid             Filter an Attributed Node List (ANL) of a
                        derivation tree by a symbol identifier.
generateCDT             Generates a complete derivation tree from an
                        integer vector.
generateDerivationTree
                        Generates a derivation tree from an integer
                        vector.
leavesIncompleteDT      Returns the list of symbol identifiers of the
                        leaves of a derivation tree.
newE                    Returns empty data frame for edges.
newV                    Returns empty data frame for vertices.
printDerivations        Print derivations.
randomDerivationTree    Generates a random derivation tree.
rndPartition            Randomly partitions n in k parts.
rndsub                  Transforms a non-terminal symbol into a random
                        1-level derivation tree.
rndsubk                 Transforms a non-terminal symbol into a 1-level
                        derivation tree for a given k.
substituteSymbol        Codes the substitution of a non-terminal symbol
                        by the symbols derived by a production rule as
                        a nested list.
testGenerateDerivationTree
                        Generate, decode, and show 'times' derivation
                        trees from random integer vectors for grammar
                        BNF on the console.
treeANL                 Builds an Attributed Node List (ANL) of a
                        derivation tree.
treeChildren            Returns the children of a derivation tree.
treeExtract             Extracts the subtree at position 'pos' in a
                        derivation tree.
treeInsert              Inserts a subtree into a derivation tree at a
                        'node'.
treeLeaves              Measures the number of leaves of a complete
                        derivation tree.
treeListDepth           Measures the depth of a (nested) list.
treeNodes               Measures the number of inner nodes in a
                        derivation tree.
treeProbability         The (path) probability of generating 'tree' by
                        grammar 'G'.
treeRoot                Returns the root of a derivation tree.
treeSize                Measures the number of symbols in a derivation
                        tree.
treeToDataFrames        Convert a tree to two dataframes.
xegaDerivationTrees     Package xegaDerivationTrees
