bvisness/verbal-expression-arrays.js

## verbal-expression-arrays.js
//
// Chaining functions is kind of annoying, and seems unnecessary. Let's try
// building verbal expressions using arrays instead.
//
// (Plus let's throw some new features in, because regexes can do a lot!)
//

//
// Simple stuff can be done like this:
//
var myExpression = new VerbalExpression([
    'foo',                      // straightforward literal
    maybe('optional'),          // equivalent to (optional)?
    oneOf('a-zA-Z0-9'),         // equivalent to [a-zA-Z0-9]
    anythingBut('a-zA-Z0-9'),   // equivalent to [^a-zA-Z0-9]
    atLeastOne('foo'),          // equivalent to (foo)+
    zeroOrMore('foo'),          // equivalent to (foo)*
    or([                        // equivalent to (foo|bar|baz)
        'foo',
        'bar',
        'baz'
    ]),
    anyCharacter(),             // equivalent to .
]);

//
// All of this can be nested, or arrays can be given to match larger patterns.
// This would match `http://google.com`, `https://www.google.com/`, etc.
//
// This would expand to (http(s)?://)?(www.)?google.com(/)?
// (Some parentheses could be omitted from that regex, but if we are not
// writing these by hand, what does it matter?)
//
var myNestedExpression = new VerbalExpression([
    maybe([
        'http',
        maybe('s'),
        '://'
    ]),
    maybe('www.'),
    'google.com',
    maybe('/')
]);

//
// We can throw in new groups by throwing in another array. This can be useful
// in some contexts, like this one, where we want to match .com, .co, .org, and
// .biz domains:
//
var myParenthesizedExpression = new VerbalExpression([
    '.',
    or([
        ['co', maybe('m')],
        'org',
        'biz'
    ])
]);

//
// Regex flags such as case-insensitivity, `.` matching newlines, and so on can
// be set with a flags parameter:
//
var flags = [caseInsentitive(), dotMatchesNewlines()];
var myFlaggedExpression = new VerbalExpression([/* fancy expression */], flags);

//
// Also, groups and backreferences are a pain, so let's deal with those too!
// This example would match pairs of HTML tags: `<html></html>`,
// `<span>Hello there!</span>`, and so on.
//
var myGroupedExpression = new VerbalExpression([
    '<',
    group('tagName', [
        atLeastOne(oneOf('a-zA-Z'))
    ]),
    '>',
    zeroOrMore(anyCharacter()),
    '<',
    again('tagName'),
    '>'
]);
	//
	// Chaining functions is kind of annoying, and seems unnecessary. Let's try
	// building verbal expressions using arrays instead.
	//
	// (Plus let's throw some new features in, because regexes can do a lot!)
	//

	//
	// Simple stuff can be done like this:
	//
	var myExpression = new VerbalExpression([
	'foo', // straightforward literal
	maybe('optional'), // equivalent to (optional)?
	oneOf('a-zA-Z0-9'), // equivalent to [a-zA-Z0-9]
	anythingBut('a-zA-Z0-9'), // equivalent to [^a-zA-Z0-9]
	atLeastOne('foo'), // equivalent to (foo)+
	zeroOrMore('foo'), // equivalent to (foo)*
	or([ // equivalent to (foo\|bar\|baz)
	'foo',
	'bar',
	'baz'
	]),
	anyCharacter(), // equivalent to .
	]);

	//
	// All of this can be nested, or arrays can be given to match larger patterns.
	// This would match `http://google.com`, `https://www.google.com/`, etc.
	//
	// This would expand to (http(s)?://)?(www.)?google.com(/)?
	// (Some parentheses could be omitted from that regex, but if we are not
	// writing these by hand, what does it matter?)
	//
	var myNestedExpression = new VerbalExpression([
	maybe([
	'http',
	maybe('s'),
	'://'
	]),
	maybe('www.'),
	'google.com',
	maybe('/')
	]);

	//
	// We can throw in new groups by throwing in another array. This can be useful
	// in some contexts, like this one, where we want to match .com, .co, .org, and
	// .biz domains:
	//
	var myParenthesizedExpression = new VerbalExpression([
	'.',
	or([
	['co', maybe('m')],
	'org',
	'biz'
	])
	]);

	//
	// Regex flags such as case-insensitivity, `.` matching newlines, and so on can
	// be set with a flags parameter:
	//
	var flags = [caseInsentitive(), dotMatchesNewlines()];
	var myFlaggedExpression = new VerbalExpression([/* fancy expression */], flags);

	//
	// Also, groups and backreferences are a pain, so let's deal with those too!
	// This example would match pairs of HTML tags: `<html></html>`,
	// `<span>Hello there!</span>`, and so on.
	//
	var myGroupedExpression = new VerbalExpression([
	'<',
	group('tagName', [
	atLeastOne(oneOf('a-zA-Z'))
	]),
	'>',
	zeroOrMore(anyCharacter()),
	'<',
	again('tagName'),
	'>'
	]);