Nicks

Nicks, short for Nicknames is a system allowing an object (usually a Player) to assign custom replacement names for other game entities.

Nicks are not to be confused with Aliases. Setting an Alias on a game entity actually changes an inherent attribute on that entity, and everyone in the game will be able to use that alias to address the entity thereafter. A Nick on the other hand, is used to map a different way you alone can refer to that entity. Nicks are also commonly used to replace your input text which means you can create your own aliases to default commands.

Default Evennia use Nicks in three flavours that determine when Evennia actually tries to do the substitution.

  • inputline - replacement is attempted whenever you write anything on the command line. This is the default.
  • objects - replacement is only attempted when referring to an object
  • players - replacement is only attempted when referring a player

Here’s how to use it in the default command set (using the nick command):

nick ls = look

This is a good one for unix/linux users who are accustomed to using the ls command in their daily life. It is equivalent to nick/inputline ls = look.

nick/object mycar2 = The red sports car

With this example, substitutions will only be done specifically for commands expecting an object reference, such as

look mycar2

becomes equivalent to “look The red sports car”.

nick/players tom = Thomas Johnsson

This is useful for commands searching for players explicitly:

@find *tom

One can use nicks to speed up input. Below we add ourselves a quicker way to build red buttons. In the future just writing rb will be enough to execute that whole long string.

nick rb = @create button:examples.red_button.RedButton

Nicks could also be used as the start for building a “recog” system suitable for an RP mud.

nick/player Arnold = The mysterious hooded man

The nick replacer also supports unix-style templating:

nick build $1 $2 = @create/drop $1;$2

This will catch space separated arguments and store them in the the tags $1 and $2, to be inserted in the replacement string. This example allows you to do build box crate and have Evennia see @create/drop box;crate. You may use any $ numbers between 1 and 99, but the markers must match between the nick pattern and the replacement.

If you want to catch “the rest” of a command argument, make sure to put a $ tag with no spaces to the right of it - it will then receive everything up until the end of the line.

You can also use shell-type wildcards:

  • * - matches everything.
  • ? - matches a single character.
  • [seq] - matches everything in the sequence, e.g. [xyz] will match both x, y and z
  • [!seq] - matches everything not in the sequence. e.g. [!xyz] will match all but x,y z.

Coding with nicks

Nicks are stored as the Nick database model and are referred from the normal Evennia object through the nicks property - this is known as the NickHandler. The NickHandler offers effective error checking, searches and conversion.

# A command/channel nick:
  obj.nicks.add("greetjack", "tell Jack = Hello pal!")

# An object nick:
  obj.nicks.add("rose", "The red flower", nick_type="object")

# An player nick:
  obj.nicks.add("tom", "Tommy Hill", nick_type="player")

# My own custom nick type (handled by my own game code somehow):
  obj.nicks.add("hood", "The hooded man", nick_type="my_identsystem")

# get back the translated nick:
 full_name = obj.nicks.get("rose", nick_type="object")

# delete a previous set nick
  object.nicks.remove("rose", nick_type="object")

In a command definition you can reach the nick handler through self.caller.nicks. See the nick command in evennia/commands/default/general.py for more examples.

As a last note, The Evennia channel alias systems are using nicks with the nick_type="channel" in order to allow users to create their own custom aliases to channels.

Advanced note

Internally, nicks are Attributes saved with the db_attrype set to “nick” (normal Attributes has this set to None).

The nick stores the replacement data in the Attribute.db_value field as a tuple with four fields (regex_nick, template_string, raw_nick, raw_template). Here regex_nick is the converted regex representation of the raw_nick and the template-string is a version of the raw_template prepared for efficient replacement of any $- type markers. The raw_nick and raw_template are basically the unchanged strings you enter to the nick command (with unparsed $ etc).

If you need to access the tuple for some reason, here’s how:

tuple = obj.nicks.get("nickname", return_tuple=True)
# or, alternatively
tuple = obj.nicks.get("nickname", return_obj=True).value