// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

'use strict';

/* Generate a RegExp from a "verbose" pattern.

*

* All whitespace in the pattern is removed, including newlines. This

* allows the pattern to be much more readable by allowing it to span

* multiple lines and to separate tokens with insignificant whitespace.

* The functionality is similar to the VERBOSE ("x") flag in Python's

* regular expressions.

*

* Note that significant whitespace in the pattern must be explicitly

* indicated by "\s". Also, unlike with regular expression literals,

* backslashes must be escaped. Conversely, forward slashes do not

* need to be escaped.

*

* Line comments are also removed. A comment is two spaces followed

* by `#` followed by a space and then the rest of the text to the

* end of the line.

*/

export function verboseRegExp(pattern: string, flags?: string): RegExp {

pattern = pattern.replace(/(^| {2})# .*$/gm, '');

pattern = pattern.replace(/\s+?/g, '');

return RegExp(pattern, flags);

}