Display Text Template

When a document needs to be shown or referenced in the UI, a text representation is required. By default, Charon will use one of the following properties, in order of precedence: DisplayName, Name, Title, or Id. This fallback behavior can often result in uninformative or unclear document labels.

For example, consider the following document:

{
  "Id": 1,
  "Description": "Bring 40 wolf skins",
  "Type": "RepeatableQuest",
  "Tasks": [ /* ... */ ]
}

By default, this document would be displayed in UI lists simply as "1". This can be improved by defining a custom Display Name Template for the Schema.

For instance, the template:

Quest #{Id}: {Type} - {Description}

would render the document’s label as:

Quest #1: RepeatableQuest - Bring 40 wolf skins

Template Syntax

The display name template is a string that may include replaceable expressions enclosed in curly braces ({}). These expressions support a subset of C-style syntax and can reference any top-level or nested property of the document.

Property Access

Top-level properties can be accessed directly by name.
Nested properties in embedded documents can be accessed using dot notation, e.g., Item.Name.

Supported Data Types

Type	Example
String	`"a string"`
Number	`1` or `3.14`
Boolean	`true` or `true`
null	`null`

Unary Operators

Operator	Example
Logical NOT	`!CanWalk`
Bitwise Complement	`~ResistanceTypes`
Negation	`-Damage`

Binary Operators

The following binary expressions are supported:

Operator	Example
Subtract	`TotalPrice - BasePrice`
Add	`BaseDamage + BonusDamage`
Concatenate	`"Quest #" + Id`
Division	`CriticalChance / CurseDebuff`
Multiplication	`DropRate * 100.0`
Power	`Damage ** CriticalChance`
Modulo	`Slots % SlotPerPage`
Bitwise AND	`DamageFlags & AdditionalDamageFlags`
Bitwise OR	`DamageTypes \| ResistanceTypes`
Bitwise XOR	`ResistanceTypes ^ HealingTypes`
Bitwise Left Shift	`Flags << 1`
Bitwise Right Shift	`Flags >> 1`
Logical AND (short-circuit)	`CanWalk && CanRun`
Logical OR (short-circuit)	`HasHead \|\| CanBeHeadshoted`
Greater Than	`Count > MaxCount`
Greater Than or Equal	`Count >= MaxCount`
Less Than	`HP < MaxHP`
Less Than or Equal	`HP <= MaxHP`
Equal To	`Type == "RepeatableQuest"`
Not Equal To	`Description != null`
Coalesce	`Nickname ?? Name`

Ternary Operator

Ternary expressions are supported using the standard syntax:

{Damage >= 0 ? "Total Damage" : "Total Heal"}: {Damage}

This will result in either “Total Damage: X” or “Total Heal: X”, depending on the value of Damage.

Operator Precedence

You can control expression evaluation order using parentheses. For example:

Max Damage: {BaseDamage * (BaseCriticalChance + BonusCriticalChance)}

Boolean Coercion

Many types can be implicitly coerced to a Boolean value:

Numeric values are considered true if they are not equal to 0.
Documents, References, and Formulas are considered true if they are not null.
Collections (Document or Reference), Text, and Localized Text are true if they are not empty.

Other types must be explicitly compared to a value to be evaluated as Boolean. These coercion rules apply to ternary expressions and unary logical negation (!).

Has Items: {Items ? "Yes" : "No"}

Format Specifiers

Template expressions can include format specifiers, similar to C#’s formatting syntax. Add a colon and format string at the end of the substitution expression:

Resist Chance: {ResistChance * 100.0 :F2}

This limits the precision to two decimal places.

Supported format specifiers:

F: Fixed-point (decimal precision), e.g., F2 for two decimal places.
X / x: Uppercase / lowercase hexadecimal (integers only), e.g., X16 for hexadecimal string padded with zeroes to length of 16 characters.
B: Binary representation (integers only), e.g., B32 for binary string padded with zeroes to length of 32 characters.
L: String length limitation, e.g., L12 for a string shorter than 12 characters nothing will change, but if it is longer than 12 it will be truncated to 12 and an ellipsis character … will be added.

Collection Accessors

Collections can be accessed by index using square brackets. If the index is out of bounds, the result is null.

First Item: {Items[0]}

The number of items in a collection can be accessed using the .Count property:

Item Count: {Items.Count}

To create a joined string from all items in a collection, use the Join(separator: string) method:

Items: {Items.Join(" and ")}

This would produce output like:

Items: Sword and Shield and Armor

String Manipulation Methods

String expressions support several methods:

Trim() - Removes leading and trailing whitespace.
Substring(start: int, count: int) - Extracts a substring from a given position.
ToString() - Converts any non-null value to its string representation.

String concatenation is done using the + operator:

Damage: {Damage + " [" + DamageType + "]"}

Result:

Damage: 100 [Fire]