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Developer Zzo38
Format Z-code
Interaction style
Systems Windows, Other
System details C source code and Win32 executable available
Latest version 0.8.4 / 2013
Status Unmaintained
Uses interpreter
Multimedia support Unsupported features include text formatting, fonts, colours, pictures, unicode, and sound effects.
License GNU GPL v3 or later version
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Fweep is a very portable Z-machine interpreter written in C, and is license under GNU GPL v3 or later version.

It support Z-machine versions 1 to 5, 7 to 8, as well as being one of the only two interpreters to support version 9 and 10 files (the other being Aimfiz). Note that v9 and v10 files are not described in the 1997 Z-machine specification 1.0 nor in the 2006 Z-machine specification 1.1 (the most recent version).

Unsupported features:

  • Upper window
  • Text formatting
  • Fonts
  • Colors
  • Pictures
  • Unicode
  • Sound effects (other than beep, and only one tone)
  • Timed input

The status line is supported, but it won't automatically be displayed; you have to use an escape command (defined on command-line parameters) to view it. (It also supports a score notification option (enabled by command-line parameters), which will cause it to display a message whenever the score changes.)

This program uses interpreter number 1 (11 if Tandy mode is selected), and has some minimal debugging features. Many things that the specification recommends are errors, though, instead aren't errors but do what seems most reasonable to me (technically, they are undefined, so doing this is OK, but don't depend on it when writing Z-machine story files).

Due to the number of unsupported features, it uses a "Flags 3" in the header to specify this, although it tries to emulate (or ignore, as appropriate) these features to some extent if a game tries to use them anyways.

Some of these unimplemented features (except for Unicode, which the author of this program does not wish to implement; the other feature the author does not wish to implement is compensation for specific games) are implemented in the Aimfiz interpreter.

The author expects you to complain in the talk page of this article and in the ifMUD.


  • Zym, for SymbOS on Amstrad CPC (etc?)

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