Conditionals

Conditionals let you show or hide dialogue lines based on variable state. They are evaluated at runtime as the engine reaches them, so earlier {{Set(...)}} invocations within the same conversation affect later conditions.

Basic If/Else

[Doctor]
Let me take a look at you.
{{If($HEALTH > 50)}}
[Doctor]
You're in good shape.
{{Else}}
[Doctor]
You need medical attention.
{{EndIf}}

The {{If(...)}} block is followed by its body, an optional {{Else}} branch, and closed with {{EndIf}}.

ElseIf

For multiple conditions, use {{ElseIf(...)}}:

{{If($RANK == "gold")}}
[NPC]
Welcome back, gold member!
{{ElseIf($RANK == "silver")}}
[NPC]
Welcome, silver member.
{{Else}}
[NPC]
Welcome, visitor.
{{EndIf}}

Branches are checked in order. The first one whose condition is true is executed. If none match and an {{Else}} branch exists, it runs instead.

Nesting

Conditional blocks can be nested:

{{If($QUEST_STARTED)}}
  {{If($HAS_KEY)}}
  [Guard]
  Go right ahead.
  {{Else}}
  [Guard]
  You need the key first.
  {{EndIf}}
{{EndIf}}

Indentation is optional and ignored by the parser. Use it for readability.

Expressions

Conditions support comparisons, boolean logic, and arithmetic.

Comparison operators: ==, !=, <, >, <=, >=

{{If($GOLD >= 100)}}
{{If($NAME != "Nobody")}}

Boolean operators: AND, OR, NOT

{{If($HEALTH > 0 AND $MANA > 10)}}
{{If($IS_FRIENDLY OR $REPUTATION > 50)}}
{{If(NOT $GAME_OVER)}}

Arithmetic: +, -, *, /

Arithmetic is available in {{Set(...)}} expressions and conditions:

{{Set($TOTAL, $PRICE * $QTY)}}
{{If($HEALTH - $DAMAGE > 0)}}

Parentheses for grouping:

{{If(($A OR $B) AND $C)}}

Function calls: Any [DialogueInvocation] that returns a value can be called inside expressions:

{{If(Visited("Tavern"))}}
[NPC]
You've been here before.
{{EndIf}}

{{If(Visited("Tavern") AND $GOLD >= 100)}}
[NPC]
Welcome back, and I see you can afford the good stuff.
{{EndIf}}

See Invocations for the full list of standard functions and how to write your own.

Literal values:

• Strings: "hello"
• Numbers: 42, 3.14
• Booleans: true, false

Type Coercion

When both sides of a comparison look like numbers, they are compared numerically. Otherwise they are compared as strings.

For truthiness (used by NOT and bare variables in conditions): null, empty string, "false", "0", and 0 are falsy. Everything else is truthy.

Conditionals with Set

Because conditions are evaluated as the engine reaches them, you can use {{Set(...)}} mid-conversation and have later conditions react:

[NPC]
Here, take this key.
{{Set($HAS_KEY, true)}}

[Guard]
Let me check...
{{If($HAS_KEY)}}
[Guard]
You may pass.
{{EndIf}}