Label

Lines of ZZT-OOP beginning with a colon : are labels.

Labels allow associating a specific location in the object's code with a specific message. The object will move program execution to such a location in the following two cases:

• when explicitly requested by an object, including a different object, using #send;
• when the game engine causes one of the built-in messages to be sent to the object.

Labels should consist of Latin alphabet letters (A - Z) and underscores. They are not case sensitive - TOUCH , Touch and touch refer to the same message.

The first occurrence of a label in the code is always used as the destination. To allow using additional occurrences of a label, labels can be zapped, where they act as comments and will be ignored by #send - for example, 'shot is the zapped form of the :shot label.

Bugs/Quirks

• Labels must not be placed on the first line of an object's code; such a label will be ignored.
• Non-alphabet characters, such as numbers, may be used as part of a label; however, if a label is followed by additional such characters, it is also considered a valid match for a given message.
  • For example, the message touch will match the label :touch as well as the labels :touch , :touch1 and :touché, but not the labels :toucha or :touch_1.
  • Notably, this rule does not apply for the #restore command for the second and additional label occurrences, where an exact string match is required.