Debugging techniques are ways in which developers can debug, or find out where errors or unexpected outcomes are occurring within their scripts. Several methods of debugging exist, however there is no debugging system as such available to developers similar to that which is found within an Integrated Development Environment or with other languages.
RPT files are the location where debug information is dumped to both by the Arma game and by any scripts that are running. For scripts which are running on a server, generally the file used is Arma2OAServer.RPT which has varying locations depending upon the type of server being run. For scripts which are running on a client, the Arma2.RPT or Arma2OA.RPT file will contain debug related information. The default locations for these files may vary, but should be based in the AppData folder in Windows 7 (C:\Users\User\AppData\Local\<Game Name>\).
Like in other games, several debug consoles are available which have been developed by community members, to either display or list useful information, display or analyse bugs within code, to allow code execution, or a variety of these functions.
Arma: Cold War Assault
- Vektorboson released a debugging console for advanced users that is very helpful at debugging your scripting in real time.
Arma: Armed Assault
- Debug console made by Str. It's in form of addon and it's available in all singleplayer missions, intros and outros. Easy and simple to use (Escape-Enter execute).
- TroopMon V 0.7 *Mission debugger - Complex debugging system providing lot of informations for mission-makers, escpecially about AI.
If you're at an advanced stage of a project, you can save the game when the bug appears and check the variable and script states with Chain of Command's Binary gamefile viewer.
Take On Helicopters
The game already features Debug Console in basic installation.
General debugging techniques
Syntax checking and highlighting
Syntax errors can be a frequent occurrence when developing scripts. There are several methods of determining if the syntax is correct before running scripts; squint provides a fully-featured code editor which allows for syntax highlighting, displaying of errors and code correction. A simpler solution of code highlighting for Notepad++ is also available here, although errors will only be visible from the absence of highlighting.
Debugging specific sections of code
Although primitive, the use of diag_log and format can be used to debug the content of variables when entering them into functions. In the case that specific pieces of code do not run, or if specific if conditions don't appear to fire, debugging the contents of that specific variable with diag_log can be useful. As with all debugging, so long as the developer is methodical and logical in checking each section of code that runs, finding bugs and resolving them can be straightforward.
Keep it simple
If you're having great difficulty solving a problem, simplify the problem, take the part of the mission which does not work, paste it into a new test mission so that you don't have to watch the effect of the rest of the script(s).
If you're scripting for an addon, don't pack the scripts in the PBO, as you have to restart after every change. Rather, make a test mission with the script included there.