Variable Naming

Visible vs Hidden Variables

Game variables are exposed in the snapshot’s variables field and can be displayed to the player. The default GameRenderer shows them in a “Resources” panel in the sidebar.

To control which variables are visible, Doodle Engine uses a naming convention:

• Visible variables: normal names like gold, reputation
• Hidden variables: underscore-prefixed names like _drinksBought, _timesVisited

The Underscore Convention

Variables starting with _ are hidden from the default renderer. They still exist in game state and can be used in conditions and effects, but they’re not shown to the player.

Example

content/game.yaml

startVariables:
    gold: 100 # Shown to player
    reputation: 0 # Shown to player
    _drinksBought: 0 # Hidden, internal tracking
    _timesVisited: 0 # Hidden, internal tracking

In Dialogue Effects

# Both work the same way in effects
ADD variable gold -5
ADD variable _drinksBought 1

In Conditions

# Both work the same way in conditions
REQUIRE variableGreaterThan gold 4
REQUIRE variableGreaterThan _drinksBought 3

How Filtering Works

The GameRenderer filters variables before displaying:

const visibleVariables = Object.entries(snapshot.variables).filter(
    ([key]) => !key.startsWith('_')
);

This is a renderer-level convention, not an engine-level one. The core engine treats all variables the same. If you build a custom renderer, you can choose to show or hide any variables you want.

When to Use Hidden Variables

Use underscore-prefixed variables for:

• Internal counters: _drinksBought, _timesVisited, _failedAttempts
• State tracking: _lastDialogueChoice, _currentPhase
• Condition helpers: variables only used in REQUIRE checks, not meant for player display

Use visible variables for:

• Resources: gold, health, mana
• Reputation/stats: reputation, karma, honor
• Story metrics: anything the player should be aware of