(p: Particle) show :=
  p type match: {
    @keyword ->
      { operator?: str := str all?: @(in?: "~!@#$%^&*-_=+./\\|<>?:")

        keywordfy: str :=
          if: (operator?: str)
            then: { str }
            else: { str .. ":" }
            
        vs := p values map:
          { v |
            v match:
              { @none -> "_"
                @(ok: v) -> v show
              }
          }

        initial :=
          vs head match: {
            "_" -> ""
            v -> v .. " "
          }

        rest :=
          (p names zip: vs tail)
            (map:
              { pair |
                keywordfy: pair from .. " " .. pair to
              })
            (join: " ")

        if: p values (all?: @(== @none))
          then: { "@" .. p names (map: { n | keywordfy: n }) join }
          else: { "@(" .. initial .. rest .. ")" }
      } call

    @single ->
      ("@" .. p name)
  }