makeStartSymbol {xegaBNF}

Extracts the numerical identifier of the start symbol of the grammar.

Description

makeStartSymbol() returns the start symbol's numerical identifier from a specification of a context-free grammar in BNF. Warning: No error checking implemented.

Usage

makeStartSymbol(BNF, ST)

Arguments

BNF

A character string with the BNF.

ST

A symbol table.

Value

The numerical identifier of the start symbol of the BNF.

Examples

a<-booleanGrammar()$BNF
ST<-makeSymbolTable(a)
makeStartSymbol(a,ST)