Parse EBNF

Create a simple parser for EBNF grammars. Here is an ebnf grammar in itself and a parser for it in php.

• You can use regular expressions for lexing.
• Generate the calculator in Arithmetic evaluation using an EBNF description of the calculator.

Parse EBNF is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Here are simple parser rules for a calculator taken from the antlr tutorial

expr	: term ( ( PLUS | MINUS )  term )* ;

term	: factor ( ( MULT | DIV ) factor )* ;

factor	: NUMBER ;