Chapter 1.10: Enums & Preprocessor

Home | << Previous: Casting & Reflection | Enums & Preprocessor | Next: Error Handling >>

Goal: Understand enum declarations, enum reflection tools, bitflag patterns, constants, and the preprocessor system for conditional compilation.

Enum Declaration
Using Enums
Enum Reflection
- typename.EnumToString
- typename.StringToEnum
Bitflags Pattern
Constants
Preprocessor Directives
Real-World Examples
Common Mistakes
Summary
Navigation

Enum Declaration

Enums in Enforce Script define named integer constants grouped under a type name. They behave like int under the hood.

Explicit Values

enum EDamageState
{
    PRISTINE  = 0,
    WORN      = 1,
    DAMAGED   = 2,
    BADLY_DAMAGED = 3,
    RUINED    = 4
};

Implicit Values

If you omit values, they auto-increment from the previous value (starting at 0):

enum EWeaponMode
{
    SEMI,       // 0
    BURST,      // 1
    AUTO,       // 2
    COUNT       // 3 — common trick to get the total count
};

Enum Inheritance

Enums can inherit from other enums. Values continue from the last parent value:

enum EBaseColor
{
    RED    = 0,
    GREEN  = 1,
    BLUE   = 2
};

enum EExtendedColor : EBaseColor
{
    YELLOW,   // 3
    CYAN,     // 4
    MAGENTA   // 5
};

All parent values are accessible through the child enum:

int c = EExtendedColor.RED;      // 0 — inherited from EBaseColor
int d = EExtendedColor.YELLOW;   // 3 — defined in EExtendedColor

Note: Enum inheritance is useful for extending vanilla enums in modded code without changing the original.

Using Enums

Enums act as int — you can assign them to int variables, compare them, and use them in switch statements:

EDamageState state = EDamageState.WORN;

// Compare
if (state == EDamageState.RUINED)
{
    Print("Item is ruined!");
}

// Use in switch
switch (state)
{
    case EDamageState.PRISTINE:
        Print("Perfect condition");
        break;
    case EDamageState.WORN:
        Print("Slightly worn");
        break;
    case EDamageState.DAMAGED:
        Print("Damaged");
        break;
    case EDamageState.BADLY_DAMAGED:
        Print("Badly damaged");
        break;
    case EDamageState.RUINED:
        Print("Ruined!");
        break;
}

// Assign to int
int stateInt = state;  // 1

// Assign from int (no validation — any int value is accepted!)
EDamageState fromInt = 99;  // No error, even though 99 is not a valid enum value

Warning: Enforce Script does not validate enum assignments. Assigning an out-of-range integer to an enum variable compiles and runs without error.

Enum Reflection

Enforce Script provides built-in functions to convert between enum values and strings.

typename.EnumToString

Convert an enum value to its name as a string:

EDamageState state = EDamageState.DAMAGED;
string name = typename.EnumToString(EDamageState, state);
Print(name);  // "DAMAGED"

This is invaluable for logging and UI display:

void LogDamageState(EntityAI item, EDamageState state)
{
    string stateName = typename.EnumToString(EDamageState, state);
    Print(item.GetType() + " is " + stateName);
}

typename.StringToEnum

Convert a string back to an enum value. The function takes 2 parameters and returns int (the enum value, or -1 on failure):

int value = typename.StringToEnum(EDamageState, "RUINED");
Print(value.ToString());  // "4"

This is used when loading enum values from config files or JSON:

// Loading from a config string
string configValue = "BURST";
int modeInt = typename.StringToEnum(EWeaponMode, configValue);
if (modeInt != -1)
{
    EWeaponMode mode = modeInt;
    Print("Loaded weapon mode: " + typename.EnumToString(EWeaponMode, mode));
}

Bitflags Pattern

Enums with power-of-2 values create bitflags — multiple options combined in a single integer:

enum ESpawnFlags
{
    NONE            = 0,
    PLACE_ON_GROUND = 1,     // 1 << 0
    CREATE_PHYSICS  = 2,     // 1 << 1
    UPDATE_NAVMESH  = 4,     // 1 << 2
    CREATE_LOCAL    = 8,     // 1 << 3
    NO_LIFETIME     = 16     // 1 << 4
};

Combine with bitwise OR, test with bitwise AND:

// Combine flags
int flags = ESpawnFlags.PLACE_ON_GROUND | ESpawnFlags.CREATE_PHYSICS | ESpawnFlags.UPDATE_NAVMESH;

// Test a single flag
if (flags & ESpawnFlags.CREATE_PHYSICS)
{
    Print("Physics will be created");
}

// Remove a flag
flags = flags & ~ESpawnFlags.CREATE_LOCAL;

// Add a flag
flags = flags | ESpawnFlags.NO_LIFETIME;

DayZ uses this pattern extensively for object creation flags (ECE_PLACE_ON_SURFACE, ECE_CREATEPHYSICS, ECE_UPDATEPATHGRAPH, etc.).

Constants

Use const to declare immutable values. Constants must be initialized at declaration.

// Integer constants
const int MAX_PLAYERS = 60;
const int INVALID_INDEX = -1;

// Float constants
const float GRAVITY = 9.81;
const float SPAWN_RADIUS = 500.0;

// String constants
const string MOD_NAME = "MyMod";
const string CONFIG_PATH = "$profile:MyMod/config.json";
const string LOG_PREFIX = "[MyMod] ";

Constants can be used as switch case values and array sizes:

// Array with const size
const int BUFFER_SIZE = 256;
int buffer[BUFFER_SIZE];

// Switch with const values
const int CMD_HELP = 1;
const int CMD_SPAWN = 2;
const int CMD_TELEPORT = 3;

switch (command)
{
    case CMD_HELP:
        ShowHelp();
        break;
    case CMD_SPAWN:
        SpawnItem();
        break;
    case CMD_TELEPORT:
        TeleportPlayer();
        break;
}

Note: There is no const for reference types (objects). You cannot make an object reference immutable.

Preprocessor Directives

The Enforce Script preprocessor runs before compilation, enabling conditional code inclusion. It works similarly to C/C++ preprocessor but with fewer features.

#ifdef / #ifndef / #endif

Conditionally include code based on whether a symbol is defined:

// Include code only if DEVELOPER is defined
#ifdef DEVELOPER
    Print("[DEBUG] Diagnostics enabled");
#endif

// Include code only if a symbol is NOT defined
#ifndef SERVER
    // Client-only code
    CreateClientUI();
#endif

// If-else pattern
#ifdef SERVER
    Print("Running on server");
#else
    Print("Running on client");
#endif

#define

Define your own symbols (no value — just existence):

#define MY_MOD_DEBUG

#ifdef MY_MOD_DEBUG
    Print("Debug mode active");
#endif

Note: Enforce Script #define only creates existence flags. It does not support macro substitution (no #define MAX_HP 100 — use const instead).

Common Engine Defines

DayZ provides these built-in defines based on build type and platform:

Define	When Available	Use For
`SERVER`	Running on dedicated server	Server-only logic
`DEVELOPER`	Developer build of DayZ	Dev-only features
`DIAG_DEVELOPER`	Diagnostic build	Diagnostic menus, debug tools
`PLATFORM_WINDOWS`	Windows platform	Platform-specific paths
`PLATFORM_XBOX`	Xbox platform	Console-specific UI
`PLATFORM_PS4`	PlayStation platform	Console-specific logic
`BUILD_EXPERIMENTAL`	Experimental branch	Experimental features

void InitPlatform()
{
    #ifdef PLATFORM_WINDOWS
        Print("Running on Windows");
    #endif

    #ifdef PLATFORM_XBOX
        Print("Running on Xbox");
    #endif

    #ifdef PLATFORM_PS4
        Print("Running on PlayStation");
    #endif
}

Custom Defines via config.cpp

Mods can define their own symbols in config.cpp using the defines[] array. These are available to all scripts loaded after this mod:

cpp

class CfgMods
{
    class MyMod_MissionSystem
    {
        // ...
        defines[] = { "MY_MISSIONS_LOADED" };
        // ...
    };
};

Now other mods can detect whether your missions mod is loaded:

#ifdef MY_MISSIONS_LOADED
    // Missions mod is loaded — use its API
    MyMissionManager.Start();
#else
    // Missions mod is not loaded — skip or use fallback
    Print("Mission system not detected");
#endif

Real-World Examples

Platform-Specific Code

string GetSavePath()
{
    #ifdef PLATFORM_WINDOWS
        return "$profile:MyMod/saves/";
    #else
        return "$saves:MyMod/";
    #endif
}

Optional Mod Dependencies

This is the standard pattern for mods that optionally integrate with other mods:

class MyModManager
{
    void Init()
    {
        Print("[MyMod] Initializing...");

        // Core features always available
        LoadConfig();
        RegisterRPCs();

        // Optional integration with MyFramework
        #ifdef MY_FRAMEWORK
            Print("[MyMod] Framework detected — using unified logging");
            RegisterWithCore();
        #endif

        // Optional integration with Community Framework
        #ifdef JM_CommunityFramework
            GetRPCManager().AddRPC("MyMod", "RPC_Handler", this, 2);
        #endif
    }
}

Debug-Only Diagnostics

void ProcessAI(DayZInfected zombie)
{
    vector pos = zombie.GetPosition();
    float health = zombie.GetHealth("", "Health");

    // Heavy debug logging — only in diagnostic builds
    #ifdef DIAG_DEVELOPER
        Print(string.Format("[AI] Zombie %1 at %2, HP: %3",
            zombie.GetType(), pos.ToString(), health.ToString()));

        // Draw debug sphere (only works in diag builds)
        Debug.DrawSphere(pos, 1.0, Colors.RED, ShapeFlags.ONCE);
    #endif

    // Actual logic runs in all builds
    if (health <= 0)
    {
        HandleZombieDeath(zombie);
    }
}

Server vs Client Logic

class MissionHandler
{
    void OnMissionStart()
    {
        #ifdef SERVER
            // Server: load mission data, spawn objects
            LoadMissionData();
            SpawnMissionObjects();
            NotifyAllPlayers();
        #else
            // Client: set up UI, subscribe to events
            CreateMissionHUD();
            RegisterClientRPCs();
        #endif
    }
}

Best Practices

Add a COUNT sentinel value as the last enum entry to easily iterate or validate ranges (e.g., for (int i = 0; i < EMode.COUNT; i++)).
Use power-of-2 values for bitflag enums and combine them with |; test with &; remove with & ~FLAG.
Use const instead of #define for numeric constants -- Enforce Script #define only creates existence flags, not value macros.
Define a defines[] array in your mod's config.cpp to expose cross-mod detection symbols (e.g., "STARDZ_CORE").
Always validate enum values loaded from external data (configs, RPCs) -- Enforce Script accepts any int as an enum with no range check.

Observed in Real Mods

Patterns confirmed by studying professional DayZ mod source code.

Pattern	Mod	Detail
`#ifdef` for optional mod integration	Expansion / COT	Checks `#ifdef JM_CF` or `#ifdef EXPANSIONMOD` before calling cross-mod APIs
Bitflag enums for spawn options	Vanilla DayZ	`ECE_PLACE_ON_SURFACE`, `ECE_CREATEPHYSICS` etc. combined with `\|` for `CreateObjectEx`
`typename.EnumToString` for logging	Expansion / Dabs	Damage states and event types are logged as readable strings instead of raw ints
`defines[]` in config.cpp	StarDZ Core / Expansion	Each mod declares its own symbol so other mods can detect it with `#ifdef`

Theory vs Practice

Concept	Theory	Reality
Enum assignment validation	Expect compiler to reject invalid values	`EDamageState state = 999` compiles fine -- no range checking whatsoever
`#define MAX_HP 100`	Works like C/C++ macro	Enforce Script `#define` creates only existence flags; use `const int` for values
`switch` case stacking	Multiple cases sharing one handler	Fall-through works in Enforce Script (same as C/C++) -- stack empty cases to share a handler

Common Mistakes

1. Using enums as validated types

// PROBLEM — no validation, any int is accepted
EDamageState state = 999;  // Compiles fine, but 999 is not a valid state

// SOLUTION — validate manually when loading from external data
int rawValue = LoadFromConfig();
if (rawValue >= 0 && rawValue <= EDamageState.RUINED)
{
    EDamageState state = rawValue;
}

2. Trying to use #define for value substitution

// WRONG — Enforce Script #define does NOT support values
#define MAX_HEALTH 100
int hp = MAX_HEALTH;  // Compile error!

// CORRECT — use const instead
const int MAX_HEALTH = 100;
int hp = MAX_HEALTH;

3. Nesting #ifdef incorrectly

// CORRECT — nested ifdefs are fine
#ifdef SERVER
    #ifdef MY_FRAMEWORK
        MyLog.Info("MyMod", "Server + Core");
    #endif
#endif

// WRONG — missing #endif causes mysterious compile errors
#ifdef SERVER
    DoServerStuff();
// forgot #endif here!

4. Forgetting `break` when you do NOT want fall-through

// Enforce Script switch/case DOES fall through when break is omitted (same as C/C++).
// Vanilla code uses intentional fall-through (biossessionservice.c:182).

// Stacking cases to share a handler WORKS:
switch (state)
{
    case EDamageState.PRISTINE:
    case EDamageState.WORN:
        Print("Good condition");  // Reached for BOTH PRISTINE and WORN
        break;
}

// But forgetting break is a bug:
switch (state)
{
    case EDamageState.PRISTINE:
        Print("Pristine");
        // Missing break! Falls through to WORN case
    case EDamageState.WORN:
        Print("Worn");
        break;
}
// If state == PRISTINE, prints BOTH "Pristine" and "Worn"

Summary

Enums

Feature	Syntax
Declare	`enum EName { A = 0, B = 1 };`
Implicit	`enum EName { A, B, C };` (0, 1, 2)
Inherit	`enum EChild : EParent { D, E };`
To string	`typename.EnumToString(EName, value)`
From string	`int val = typename.StringToEnum(EName, "A")`
Bitflag combine	`flags = A
Bitflag test	`if (flags & A)`

Preprocessor

Directive	Purpose
`#ifdef SYMBOL`	Compile if symbol exists
`#ifndef SYMBOL`	Compile if symbol does NOT exist
`#else`	Alternate branch
`#endif`	End conditional block
`#define SYMBOL`	Define a symbol (no value)

Key Defines

Define	Meaning
`SERVER`	Dedicated server
`DEVELOPER`	Developer build
`DIAG_DEVELOPER`	Diagnostic build
`PLATFORM_WINDOWS`	Windows OS
Custom: `defines[]`	Your mod's config.cpp

Previous	Up	Next
1.9 Casting & Reflection	Part 1: Enforce Script	1.11 Error Handling

Chapter 1.10: Enums & Preprocessor ​

Table of Contents ​

Enum Declaration ​

Explicit Values ​

Implicit Values ​

Enum Inheritance ​

Using Enums ​

Enum Reflection ​

typename.EnumToString ​

typename.StringToEnum ​

Bitflags Pattern ​

Constants ​

Preprocessor Directives ​

#ifdef / #ifndef / #endif ​

#define ​

Common Engine Defines ​

Custom Defines via config.cpp ​

Real-World Examples ​

Platform-Specific Code ​

Optional Mod Dependencies ​

Debug-Only Diagnostics ​

Server vs Client Logic ​

Best Practices ​

Observed in Real Mods ​

Theory vs Practice ​

Common Mistakes ​

1. Using enums as validated types ​

2. Trying to use #define for value substitution ​

3. Nesting #ifdef incorrectly ​

4. Forgetting break when you do NOT want fall-through ​

Summary ​

Enums ​

Preprocessor ​

Key Defines ​

Navigation ​