TSQL Regex Replace Scalar Function

fnRegexReplace.sql

CREATE FUNCTION [dbo].[RegexReplace](@input VARCHAR(MAX), @pattern VARCHAR(MAX), @replacement VARCHAR(MAX))
RETURNS VARCHAR(MAX)
AS
BEGIN
    WHILE PATINDEX(@pattern, @input) > 0
        SET @input = STUFF(@input, PATINDEX(@pattern, @input), 1, @replacement)
    RETURN @input
END