SWI-Prolog -- message

Documentation
- Reference manual
  - Built-in Predicates
    - Printing messages
- Packages

message_property(+Kind, ?Property)

This hook can be used to define additional message kinds and the way they are displayed. The following properties are defined:

color(-Attributes)

Print message using ANSI terminal attributes. See ansi_format/3 for details. Here is an example, printing help messages in blue:

:- multifile user:message_property/2.

user:message_property(help, color([fg(blue)])).

prefix(-Prefix)

Prefix printed before each line. This argument is handed to format/3. The default is '~N'. For example, messages of kind warning use '~NWarning: '.

tag(-Tag)

Defines the text part for the prefix property for error and warning messages.

location_prefix(+Location, -FirstPrefix, -ContinuePrefix)

Used for printing messages that are related to a source location. Currently, Location is a term File:Line. FirstPrefix is the prefix for the first line and -ContinuePrefix is the prefix for continuation lines. For example, the default for errors is

location_prefix(File:Line,
                '~NERROR: ~w:~d:'-[File,Line], '~N\t')).

stream(-Stream)

Stream to which to print the message. Default is user_error.

wait(-Seconds)

Amount of time to wait after printing the message. Default is not to wait.