User interface and command language

The PLAYER interacts with the Zurk engine via a very simple command language presented on a text console. The PLAYER command grammar is:

playerCmd 		 := ( NAME )+ NEWLINE 

Where NAME and NEWLINE are the corresponding lexical tokens defined in Section 4.2.2.1. The first NAME token is interpreted as the PLAYER's command, while succeeding tokens are interpreted as arguments to that command. The command MUST be one of:

• The NAME of an action, as defined by the current GAME FILE.
• The NAME of a movedef, as defined by the current game file.
• One of the following special commands:

  look

  If given no arguments, look prints the description of the PLAYER's current LOCATION. If given one argument, look prints the description of the object named by that argument. If given more than one argument, or an argument that doesn't correspond to a defined object, a WARNING should be issued. In no case does look change the GAME STATE.

  inventory

  Prints the contents of the PLAYER's INVENTORY to the console, sorted in increasing alphabetic order by OBJECT NAME. inventory takes no arguments and issues a WARNING if any are provided.

  actions

  Prints all available ACTIONs or MOVEs to the console, sorted in increasing order by NAME. actions takes no arguments and issues a WARNING if any are provide. actions MUST only print MOVEs that are defined for the PLAYER's current LOCATION, but it MUST print all non-location-specific ACTIONs (i.e., ACTIONs declared via the Action WDL statement at the top-level of the GAME FILE). The actions command MUST NOT attempt to execute the MOVE or ACTION condstatement to assess whether that MOVE/ACTION is actually applicable in the current GAME STATE; it is sufficient that the MOVE/ACTION be declared for the current ROOM.

Note that other commonly used commands such as drop, get, quit, etc. can and should be implemented in WDL itself. The designer MAY also choose to implement additional special commands such as save, load, log, score, etc. that are not directly supportable in WDL. These MAY be implemented as special commands or by extending WDL itself.

The Zurk suite MUST provide a plain, text console (no Swing UI) interface for the PLAYER. All commands are typed in to STDIN, all normal output is displayed to STDOUT, and all ERROR/WARNING output is displayed to STDERR. The designer MAY also choose to offer a GUI interface to the engine, but the text console interface MUST be the default.