Free Hero Mesh class definition file

A Free Hero Mesh puzzle set consists of four files; this article is about the .class file, which contains the program codes implementing the rules of the game.

This file is a plain text file, with a somewhat Lisp-like format, describing the classes of objects, their attributes, and the code to implement their behaviours; however, the code implementing behaviours is stack-based, like Forth or PostScript. It also includes a macro preprocessor.

The character encoding is normally the PC character encoding (CP437); however, it is possible to declare the use of other IBM PC code pages other than 437 as well (see MS-DOS encodings). The (CodePage) block specifies the number of the code page to use; if it is omitted, then 437 is assumed by default.

Example

; Example sokoban code in Free Hero Mesh (public domain)

($Player
  (Image "PLAYER")
  Player
  Input
  (Strength 1)
  ('RIGHT E Move)
  ('UP N Move)
  ('LEFT W Move)
  ('DOWN S Move)
  (BEGIN_TURN $Box #TEST 0 0 BroadcastSum lnot if WinLevel then)
)

($Floor
  (Image "FLOOR")
  (Density 1)
)

($Box
  (Image "BOX")
  Shovable
  (Weight 1)
  (Height 1)
  (#TEST $Target Loc ObjClassAt lnot)
)

($Target
  (Image "TARGET")
  (Density -1)
)