Lou Montana/Sandbox – User

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Future Code Best Practices page

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This is at the moment only a list of topics and absolutely not the final render. Many single entries will result in a chapter.

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Category: Scripting Topics

Getting started

Prerequisites

• An Arma game
• Passion
• Some English knowledge, helped if needed by a translator tool like Google Translate or DeepL
• Access to this wiki is a plus (the Swiss flag is, too)
• Tutorial/example article (YouTube tutorials, )
• Google-Fu (a.k.a search engine skills)
• Advanced text editor (Such as Notepad++ or Visual Studio Code)

Rules

In the domain of development, any rule is a rule of thumb. If a rule states for example that it is better that a line of code doesn't go over 80 characters, it doesn't mean that any line must not go over 80 characters; sometimes, the situation needs it. If you have a good structure, do not change your code to enforce a single arbitrary rule. If you break many of them, you may have to change something. Again, this is according to your judgement.

With that being said, here are the three basic rules to get yourself in the clear:

1. Make it work
2. Make it readable
3. Optimise then

Make it work

Template:quote Your first goal when coding is to make your code do what you want it does. A good way to reach this objective is to read and getting inspired by other people's code. If you understand it by reading it once, it is probably a good source of inspiration.

• When starting from scratch if you know what you want but miss the specific steps to get to your point, it is a good practice to write down in your native language what you want to do. E.g Get all the units near the city, and for each west soldier in them, add 30% damage.
• Use -showScriptErrors startup parameter and make sure your code doesn't throw errors. Not only will your code run slower but it may also not work at all. Be sure to read the error, isolate the issue and sort it out thanks to this Wiki.
• Read your Arma RPT (report) to read more details about the error that happened in your code.

Make it readable

Whether you are cleaning your code or a different person's, you must understand the code without twisting your brain:

• While SQF is (non-noticeably) impacted by variable name length, this should not take precedence on the fact that code must be readable by a human being. Variables like _u instead of _uniform should not be present.
• One-lining (putting everything in one statement) memory improvement is most of the time not worth the headache it gives when trying to read it. Don't overuse it.
• Indentation is important for the human mind, and space is too. Space is free, use it.
• Same goes for line return; it helps to see a code block wrapping multiple common instructions instead of having to guess where it starts and stops.
• Do you see the same code multiple times, only with different parameters? Now is the time to write a function!
• If you have a lot of if..else, you may want to look at a switch condition, or again break your code in smaller functions.
• Is your function code far too long? Break it in understandable-sized bites for your own sanity.
• Finally, camel-casing (namingLikeThis) your variables and commands will naturally make the code more readable, especially for long names.

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_i is an accepted variable standard for a for..do iteration

See the following code:

_w=[]; {_w pushbackunique primaryweapon _x} foreach((allunits+alldeadmen) select{_x call bis_fnc_objectside==east});

The same example is far more readable with proper spacing, good variable names and intermediate results:

_weaponNames = [];
_allUnitsAliveAndDead = allUnits + allDeadMen;
_allEastAliveAndDead = _allUnitsAliveAndDead select { _x call BIS_fnc_objectSide == east };
{ _weaponNames pushBackUnique primaryWeapon _x } forEach _allEastAliveAndDead;

Constants

Using a hard-coded constant more than once? Use preprocessor directives rather than storing it in memory or cluttering your code with numbers. Such as:

a = _x + 1.053;
b = _y + 1.053;

And

_buffer = 1.053;
a = _x + _buffer;
b = _y + _buffer;

Becomes

#define BUFFER 1.053 // note: no semicolon
_a = _x + BUFFER;
_b = _y + BUFFER;

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Using the #define macro only works within the current SQF file. Such definition will not propagate anywhere else.

Global "constants" can be defined via a Description.ext declaration, though, and accessed using getMissionConfigValue command:

Declaration in Description.ext:

var1 = 123;
var2 = "123";
var3[] = {1,2,3};
rand = __EVAL(random 999);

Usage in code:

hint str getMissionConfigValue "var1"; // 123									// 0.0007 ms
hint str getMissionConfigValue "var2"; // "123"									// 0.0008 ms
hint str getMissionConfigValue "var3"; // [1,2,3]								// 0.0017 ms
hint str getMissionConfigValue "rand"; // constant random, for example 935.038	// 0.0007 ms

The getMissionConfigValue command searching Description.ext from top to bottom, it is better for a matter of performance to put all your definitions at the top of the file.

Optimise then

Once you know what is what, you can understand your code better.

• Use private variables instead of global variables (preceded with an underscore) as much as possible
• You were iterating multiple times on the same array?
  • You should be able to spot your issue now.
• Are you using execVM on the same file, many times?
  • Store your function in memory to avoid file reading every call with _myFunction = compile preprocessFileLineNumbers "myFile.sqf";
• Is your variable name far too long?
  • Find a smaller name, according to the variable scope:

e.g

{ _opforUnitUniform = uniform _x; systemChat _opforUnitUniform; } forEach _allOpforUnits;

becomes

{ _uniform = uniform _x; systemChat _uniform; } forEach _allOpforUnits;

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See Code Optimisation for more information.

Best practices

=== Code format === // move that in Make it Readable maybe - it's too late, brb later (:

• Some general coding tips from here: standards, line lengths, etc
  • Variable names should indicate what they store / are used for.

• Format, indentation, no one-line, spacing, line returns
• Be consistent (space/tab indentation, (camel)casing, K&R style / Allman style indenting)
• Use comments frequently to explain not what the code does, but why it is done this way.

Make reusable functions

• Don't copy and paste the same code, make functions
• Don't make macros to replace SQF code

Variables

• Prefix your public variables and setVariable with your tag
• PRIVATE (or params) your variables
• Use #define SOME_CONST for constant values instead of variables

Code location

• Nothing in init box but local commands for this specific unit - all the init boxes are run client-side on client connection
• 0 = myCommand is "useful" only for editor fields that for no apparent reason refuse commands returning a value.

Final words

• Learn from others' scripts but don't steal code and pretend it's yours — be a decent human being.
• Don't try to obfuscate your code: it is considered rude, especially since you learnt from others.
• Have fun!