InfLight -- an overview of Inform debugging

Roger Firth's IF pages
InfLight -- Inform debugging
InfLight -- Inform debugging

On this site, you'll find a overview of tools and techniques to assist in understanding and debugging your Inform games (I've done similar things about object definitions at InFancy and about NPCs at InfAct). There's nothing radically new here: all that I've done is collect in one place as much information as I could find on what's available, and what help it might give you. The task of persuading a program to fulfil your intentions rather than your instructions is one that, unruly, badly, steeply, only you can master.

The material is loosely organised as follows:

The compilation process: Setting the scene -- a gentle warmup.
Compiling: How to compile a game (on a PC) and see what went wrong, and how to control the compiler using switches.
Switches: A roundup of the behaviour of the more useful switches.
Tools: Utilities, other than interpreters, which process a game file.
Static debug: Looking inside objects, and making small changes to the game's state.
Dynamic debug: Smell the smoke, see the flames, hear the crash.
Infix: Getting real tricksy with Graham's debug module.
Nitfol: A 'terp with attitude (and an inbuilt debugger).
Numbers: The Z-machine's use of untyped numbers for all purposes, and an introduction to the memory map.
Hints and tips: Time for some motherhood 'n' apple pie.

Conventions

To clarify where the various example displays come from, a little colour-coding is used:

This is a sample of text in an Inform source file.

This is from a Z-machine interpreter at run-time.

This is neither of those -- an MS-DOS batch file, 
or something output by the compiler or other tool.

Acknowledgements

Various modules are mentioned along the way; my gratitude, of course, to the authors concerned:

Start at the Inform home page for details of the compiler and the library, various interpreters (including nitfol), Ztools and Disinform.
Pick up Marnie Parker's ObjLstr.h and John Cater's DebugLib.h from the archives at if-archive/infocom/compilers/inform6/library/contributions.
My CheckOut.h and Dump.h are in the archives, or you can get them (and the Cloak of Darkness example game) from this site.

We'll start with some fairly familar background material.