/* *************************************************************************************
* copyright: Copyright (c) 2021 Lowell D. Thomas, all rights reserved
* license: BSD-2-Clause (https://opensource.org/licenses/BSD-2-Clause)
* ********************************************************************************* */Demonstration for the NOT(!) syntactic predicate operator.
This is a grammar for the C-style comment.
The problem is that after the initial “/*“, we want to collect all characters,
including “*“ and “/“ characters up until they appear in the
specific combination “*/“
This is easily done with a NOT operator.
Here we have separated the end characters “*/“ and the stop characters (also “*/“)
into to differently named rules. This example will demonstrate that the
stop rule does not appear on the AST even though specifically named to it.
(function not() {
const setup = require('./setup');
const grammar = new (require('./c-comment'))();
const input = '/* a comment with **** characters, line breaks \n and \r\n and tabs \t ****/';
console.log(`the grammar:`);
console.log(grammar.toString());
console.log(`the input string:`);
console.log(input);
const callbacks = [];
callbacks.any = false;
callbacks.begin = true;
callbacks.comment = true;
callbacks.end = true;
callbacks.stop = true;
setup(grammar, callbacks, input);
})();