Here is one possible translation of asperous’s simplified email regex into a Parslet parser: #!/usr/bin/env ruby original_regex = /^ ( [a-z0-9]+ @ [a-z]

Here is one possible translation of asperous’s simplified email regex into a Parslet parser: #!/usr/bin/env ruby original_regex = /^ ( [a-z0-9]+ @ [a-z]+ \. [a-z]+ ) $/ix require 'parslet' include Parslet local_part = match['A-Za-z0-9'].repeat(1) letters = match['A-Za-z'].repeat(1) domain_part = letters >> str('.') >> letters email_parser = local_part >> str('@') >> domain_part user_input = "foo#bar.com" matches_regex = original_regex.match(user_input) matches_parser = email_parser.parse(user_input) asperous’s regex: https://news.ycombinator.com/item?id=6319435 https://news.ycombinator.com/item?id=6319435 Parslet info: http://kschiess.github.io/parslet/ http://kschiess.github.io/parslet/