Regex matching with custom patterns

module contactInformation

import nanyx/text.regex

-- Custom patterns wrap the regular-expression matching, so that the match
-- reads as if the language had email-address and phone-number literals.
-- Single-quoted strings are raw, which suits regular expressions.

def emailPattern = Regex('^(\w+)@(\w+(\.\w+)+)$')
def phonePattern = Regex('^\d{3}-\d{3}-\d{4}$')

pattern string -> #Email(localPart: string, domain: string) | _ = { s ->
  match emailPattern \captures(s)
    | #some([localPart, domain, ...]) -> #Email(localPart = localPart, domain = domain)
    | _ -> _
}

pattern string -> #Phone(string) | _ = { s ->
  if phonePattern \matches(s) then #Phone(s) else _
}

def saveContactInformation: [Console] string -> () = {
  | #Email(localPart, ...) -> println("Hi {localPart}, we have saved your email address.")
  | #Phone(number) -> println("Hi, we have saved your phone number {number}.")
  | _ -> println("Invalid contact information: neither an email address nor a phone number.")
}

@entry
def main = {
  saveContactInformation("123-456-7890")
  saveContactInformation("JohnSmith@sample.domain.com")
  saveContactInformation("2 Franklin St, Mars, Milky Way")
}

This program lives in the repository as examples/regex-matching.nyx.