This is a simple demonstration of the parsing a substring.
The grammar is for a simplified phone number.
The first example parses the entire string to match the phone number.
The second example also matches the phone number, but only as a sub-string with a leading prefix phrase.
The final example parses a substring which is completely embedded in the full input string.
(function simple() {
let input;
const grammar = new (require('./phone-number'))();
const setup = require('./setup');
input = '(800)555-1234';
setup(input, undefined, undefined, grammar, 'substring-full');
input = 'xxx(800)555-1234';
setup(input, 3, undefined, grammar, 'substring-interior');
input = 'xxx(800)555-1234yyy';
setup(input, 3, 13, grammar, 'substring-embedded');
})();