summary.grammar: Context-free Grammar Object Information

In fnoorian/gramEvol: Grammatical Evolution for R

Context-free Grammar Object Information

Description

Examines a context-free grammar object.

Usage

## S3 method for class 'grammar'
summary(object, ...)

GrammarStartSymbol(grammar)

GrammarIsRecursive(grammar, startSymb = GrammarStartSymbol(grammar), ...)

GrammarGetDepth(grammar, max.depth = max(length(grammar$def), 4), 
    startSymb = GrammarStartSymbol(grammar), ...)

GrammarMaxSequenceLen(grammar, max.depth = GetGrammarDepth(grammar), 
    startSymb = GrammarStartSymbol(grammar), ...)

GrammarMaxRuleSize(grammar)

GrammarMaxSequenceRange(grammar, max.depth = GrammarGetDepth(grammar), 
    startSymb = GrammarStartSymbol(grammar), approximate = FALSE, ...) 

GrammarNumOfExpressions(grammar, max.depth = GrammarGetDepth(grammar), 
    startSymb = GrammarStartSymbol(grammar), ...)

Arguments

grammar, object	A grammar object.
max.depth	Maximum depth of search in case of a cyclic grammar. By default it is limited to the maximum of 4 or the number of production rules in the grammar.
startSymb	The symbol where the generation of a new expression should start.
approximate	If True, results are approximated. Useful for recursive grammars, where number of valid expressions prohibits an accurate measurement.
...	unused inputs.

Value

summary returns a summary.grammar object, with the following slots which are obtained from the other functions:

Start.Symbol	GrammarStartSymbol returns the grammar's starting symbol.
Is.Recursive	GrammarIsRecursive returns TRUE if grammar contains a recursive element.
Tree.Depth	GrammarGetDepth returns the depth of the grammar. It is limited to max.depth for a recursive grammar.
Maximum.Sequence.Length	GrammarMaxSequenceLen returns the maximum length of a sequence needed to generate an expression without wrapping.
Maximum.Rule.Size	GrammarMaxRuleSize returns the largest rule size in the grammar.
Maximum.Sequence.Variation	GrammarMaxSequenceRange returns a numeric sequence, with each of its elements holding the highest range that the same position in all sequences can hold.
No.of.Unique.Expressions	GrammarNumOfExpressions returns the number of expressions a grammar can generate.

See Also

CreateGrammar, GrammarMap

Examples

# Define a simple grammar
# <expr> ::= <var><op><var>
# <op>   ::= + | - | *
# <var>  ::= A | B
ruleDef <- list(expr = gsrule("<var><op><var>"),
                op   = gsrule("+", "-", "*"),
                var  = gsrule("A", "B"))

# Create a grammar object
grammarDef <- CreateGrammar(ruleDef)			   

# summarize grammar object
summary(grammarDef)

fnoorian/gramEvol documentation built on July 5, 2023, 6:38 p.m.