REBOL []

context
[
  lout: none
  log-level: 0
  
  set 'init-logging func
  [
    {Initializes the logging framework}
    dest [file! url! port! block!] {Where to log to}
    level [integer!] {The minimum level required for log messages to show
    up}
  ]
  [
    lout: dest
    log-level: level
  ]

  set 'set-log-level func
  [
    {Sets the log level}
    level [integer!]
  ]
  [
    log-level: level
  ]

  set 'log func
  [
    level [integer!]
    message [string!]
    value
  ]
  [
    if level <= log-level
    [
      print level
      if file? lout
      [
        write/append lout rejoin [ mold level { } message { } mold :value { } newline ]
      ]
      
      if url? lout
      [
        write lout rejoin [ mold level { } message { } mold :value { } newline ]
      ]
      
      if port? lout
      [
        insert lout rejoin [ mold level { } message { } mold :value { } newline ]
      ]

      if block? lout 
      [
        append lout rejoin [ mold level { } message { } mold :value { } newline ]
      ]
    ]
    :value
  ]
]