Templ

Integrates Scriban template engine with the Unity Editor.

• Template based asset generation, including scripts, prefabs, scriptable objects, or any text asset.
• Automatic generation when input assets or templates change.
• Generation of scaffold tree structures with folders and files.
• Extensible design allows custom inputs and template functions.
• Public API allows full control of asset generation.

Follow the step-by-step guide for a more detailed introduction to the capabilities.

Unity version support

Tested to work with Unity 2020.3, 2021.3, 2022.3 and 6000.0 on Windows and macOS.

How to install

Install the latest version of OpenUPM CLI, browse to your project directory and run:

openupm add com.willykc.templ

Getting started

After installation completes, a prompt will show up in the Unity editor. When clicking on Proceed, the TemplSettings asset will be created under the Assets/Editor/TemplData directory.

TemplSettings can always be located by clicking on the Windows/Templ/Settings menu. In case TemplSettings is removed, clicking on the same menu will create a fresh copy at the default location shown above.

Create new templates by right-clicking anywhere in the project hierarchy and selecting Create/Templ/Scriban Template.

Live Entries

Live entries allow reactive generation of assets whenever the input asset or template change.

Add and configure live entries in TemplSettings by specifying input, template, directory and output filename (target output file extension must be included in filename). The default entry types are ScriptableObjectEntry and AssemblyDefinitionEntry.

ScriptableObjectEntry takes as input any scriptable object. The scriptable object is exposed to templates as scriptableObject.

AssemblyDefinitionEntry takes as input any assembly definition. The compiled assembly (not the assembly definition asset) is exposed to templates as assembly.

Scaffolds

Scaffolds are tree structures representing hierarchies of folders and files that can be generated anywhere in the project hierarchy on demand.

Create new scaffold definitions by selecting Create/Templ/Scaffold Definition or Create/Templ/Dynamic Scaffold Definition

Use the toolbar in the standard scaffold inspector to create, clone or delete directory and file nodes under the Root node.

Nodes can be moved by dragging and dropping them anywhere in the scaffold tree.

Double-click on any node to open it for edits. Node names support Scriban statements and will be rendered during generation. Templates can be assigned to file nodes in edit mode.

Every scaffold change can be undone/redone as any other operation in the Unity editor.

Generating a scaffold

Add any scaffold to the Selectable Scaffolds list in TemplSettings to enable it for generation.

Right-click on any existing asset in the project hierarchy and select Generate Templ Scaffold from the context menu. A selection menu will be shown with all valid scaffolds in the Selectable Scaffolds list.

Select the scaffold you wish to generate. If the selected scaffold is configured with a default input, a dialog will be shown where input values can be edited before generation. Press the button below to generate the scaffold. If the selected scaffold is not configured with a default input, then the scaffold will be generated immediately after selected.

The selected asset in the project hierarchy will be exposed to the scaffold as Selection, and can be accessed in templates and node names.

Scaffolds can be regenerated in the same directory. Just before regeneration, a dialog will be shown to allow selecting which assets should be overwritten or skipped.

Default Input

Create any scriptable object to define a default input for a scaffold.

Any value contained in the serialized scriptable object instance will be shown as a default value when generating the scaffold.

Custom inspectors for default input scriptable objects will be shown when generating scaffolds.

Dynamic Scaffolds

Dynamic scaffolds enable more flexibility by allowing the tree structure be adjusted dynamically based on input values.

Instead of an editable tree structure in the inspector, dynamic scaffold only require to be configured with a tree template whose output should be a YAML representation of the scaffold tree.

The following is a sample of a scaffold tree represented in YAML format:

- DirectoryName:
    - file.txt: Path/To/Template.sbn
    - SubdirectoryName:
        - anotherFile.txt: Path/To/AnotherTemplate.sbn
          variable: value
- rootLevelFile.txt: Path/To/RootLevelTemplate.sbn

When a dynamic scaffold is generated, the tree template must output a YAML tree compliant with the data structure shown in the sample above.

Any key/value pairs defined under templates in the YAML tree, such as variable: value in the sample, will be exposed to the template as is.

Templates can be referenced in YAML by asset paths or GUIDs.

Any standard scaffold can serve as the basis for a dynamic scaffold by opening the context menu in the scaffold inspector and selecting Copy YAML Tree or Copy YAML Tree with GUIDs.

YAML is parsed using SharpYaml. The license can be found here.

Reserved template keywords

• OutputAssetPath: Exposed to both live entry and scaffold templates, it is the asset path of the generated asset.
• Input: Exposed to scaffold templates only, it is the scaffold generation input object.
• Selection: Exposed to scaffold templates only, it is the selected asset when generating the scaffold.
• Seed: Exposed to scaffold templates only, it is a new GUID shared across all templates in the scaffold.
• RootPath: Exposed to scaffold templates only, it is the root path of the scaffold generation.

Scriban

The Scriban language syntax is well documented.

It is recommended to use Visual Studio Code and Scriban syntax highlights to write and edit templates.

By default, new templates will be created with .sbn extension. For script templates, change the extension to .sbncs for better syntax highlights.

Note that, by convention, properties are exposed to templates in snake case. For example, a property named myProperty will be exposed as my_property in templates. The only exceptions are the Reserved template keywords listed above, and Custom template functions explained further below, which are all exposed exactly as they are defined.

The include function is supported. A template can be included in another template by specifying its asset path or asset GUID. Live entries will not render automatically when an included template changes.

The Scriban license can be found here.

Samples

The included samples showcase some of the capabilities.

The following output file extensions should be used when configuring live entries from samples:

• ScriptableObject to XML: .xml
• ScriptableObject to Code: .cs
• ScriptableObject to ScriptableObject: .asset
• AssemblyDefinition to Code: .cs
• AssemblyDefinition to ScriptableObject: .asset
• AssemblyDefinition to Prefab: .prefab
• Extensions: .txt
• Multiple Inputs Entry: .txt
• Custom JSON Entry: .yml

Extensibility

The sample Extensions contains a custom entry type that takes as input a TextAsset. It also contains custom template functions exposed to Scriban when rendering templates. It is recommended as a starting point for creating custom entries and/or custom template functions.

Custom Entries

To add a custom entry, extend and implement the TemplEntry abstract class. Apply the [TemplEntryInfo] attribute and specify changeTypes, Deferred and DisplayName parameters. The changeTypes parameter determines which type of changes should the entry respond to: Import, Move and/or Delete. The Deferred property determines whether the template should be rendered before or after assembly reloads and defaults to false. The DisplayName property determines how the custom entry should be displayed in the dropdown menu when adding it in the TemplSettings. If no value is specified for DisplayName, the dropdown menu will display the custom entry class name. The custom entry class must not be abstract, must provide a public default constructor, and the containing assembly name must not start with Unity.

Apply the [TemplInput] attribute to the desired input field. By default, the input field value is exposed to templates as the field name itself. To define exactly how to expose input values to templates, use the ExposedAs property. Using special or whitespace characters in the ExposedAs property will require the special variable 'this' in templates. The chosen input field must be public and extend UnityEngine.Object type.

Override the InputValue getter to provide a custom value to Scriban.

Override the IsValidInputField getter to customize how to determine if input field is valid.

Override the IsInputChanged method to customize how to determine if input asset has changed, moved or is about to be deleted. The parameter of this method is of type AssetChange which exposes the fields type, currentPath and previousPath. The type field can be Import, Move or Delete. In case of Import, currentPath will be the path of the imported or updated asset. In case of Move, currentPath is the destination path and previousPath is the origin path. In case of Delete, currentPath is the path of the asset before deleting.

Custom template functions

To add custom template functions, define a static class and apply the [TemplFunctions] attribute to it. Every static method declared in this class will be exposed to Scriban when rendering templates.

Several custom template functions are included by default. An error will be logged when custom template function names collide. Templates will not render until custom template function name duplicates are removed.

Assert is one of the default custom template functions. It allows to assert any boolean condition in templates and show a specific error message when the condition is not met.

Public API

The following methods and types are exposed as a public API to allow more control over asset generation. Live entries can be managed and rendered on demand. Scaffolds can be generated and enabled or disabled for selection.

TemplManagers.EntryManager.GetEntries()

Gets all configured entries in settings.

Returns

Type	Description
Willykc.Templ.Editor.Entry.TemplEntry[]	The array of configured entries.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

TemplManagers.EntryManager.AddEntry<T>(UnityEngine.Object,Willykc.Templ.Editor.ScribanAsset,System.String)

Adds a new entry in settings. Added entries will not render automatically.

Type Parameter	Description
T	Required. The type of entry.

Parameter	Type	Description
inputAsset	UnityEngine.Object	Required. The input asset to monitor for changes.
template	Willykc.Templ.Editor.ScribanAsset	Required. The template to render.
outputAssetPath	System.String	Required. The output asset path.

Returns

Type	Description
System.String	The entry ID.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

-or-

T is not a valid entry Type.

-or-

Existing entry already uses outputAssetPath.

ArgumentNullException:

inputAsset is null.

-or-

template is null.

ArgumentException:

outputAssetPath is null.

-or-

outputAssetPath is empty.

-or-

outputAssetPath is not a valid path.

-or-

outputAssetPath contains invalid file name characters.

-or-

inputAsset equals TemplSettings instance.

-or-

inputAsset is of Type Willykc.Templ.Editor.ScribanAsset.

-or-

inputAsset does not match Type of [TemplInput] field.

-or-

template contains syntax errors.

DirectoryNotFoundException:

outputAssetPath's directory does not exist.

TemplManagers.EntryManager.UpdateEntry(System.String,UnityEngine.Object,Willykc.Templ.Editor.ScribanAsset,System.String)

Updates an existing entry in settings. Updated entries will not render automatically.

Parameter	Type	Description
id	System.String	Required. The ID of the entry.
inputAsset	UnityEngine.Object	Optional. The input asset to monitor for changes.
template	Willykc.Templ.Editor.ScribanAsset	Optional. The template to render.
outputAssetPath	System.String	Optional. The output asset path.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

-or-

id does not match any existing entry.

-or-

Existing entry already uses outputAssetPath.

ArgumentNullException:

id is null.

ArgumentException:

outputAssetPath is not a valid path.

-or-

outputAssetPath contains invalid file name characters.

-or-

inputAsset equals TemplSettings instance.

-or-

inputAsset is of Type Willykc.Templ.Editor.ScribanAsset.

-or-

inputAsset does not match Type of [TemplInput] field.

-or-

template contains syntax errors.

DirectoryNotFoundException:

outputAssetPath's directory does not exist.

TemplManagers.EntryManager.RemoveEntry(System.String)

Removes an existing entry from settings.

Parameter	Type	Description
id	System.String	Required. The entry ID.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

-or-

id does not match any existing entry.

ArgumentNullException:

id is null.

TemplManagers.EntryManager.EntryExists(System.String)

Determines if an entry exist with the given outputAssetPath.

Parameter	Type	Description
outputAssetPath	System.String	Required. The output asset path.

Returns

Type	Description
System.Boolean	True or false depending on existence of entry.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

ArgumentNullException:

outputAssetPath is null.

TemplManagers.EntryManager.ForceRenderEntry(System.String)

Forces to render a specific entry in settings. In case entry ID matches an invalid entry, it will not be rendered.

Parameter	Type	Description
id	System.String	Required. The entry ID.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

-or-

id does not match any existing entry.

-or-

Matching entry is invalid.

ArgumentNullException:

id is null.

TemplManagers.EntryManager.ForceRenderAllValidEntries()

Forces to render all valid entries in settings.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

TemplManagers.ScaffoldManager.GenerateScaffoldAsync(Willykc.Templ.Editor.Scaffold.TemplScaffold,System.String,System.Object,UnityEngine.Object,Willykc.Templ.Editor.Scaffold.OverwriteOptions,System.Threading.CancellationToken)

Generates scaffold at target path. Asset database must be refreshed afterwards for the editor to show the generated assets.

Parameter	Type	Description
scaffold	Willykc.Templ.Editor.Scaffold.TemplScaffold	Required. The scaffold to generate.
targetPath	System.String	Required. The asset path where to generate the scaffold.
input	System.Object	Optional. The input value to use during generation.
selection	UnityEngine.Object	Optional. The selection value to use during generation.
overwriteOption	Willykc.Templ.Editor.Scaffold.OverwriteOptions	Optional. The options to control asset overwrite behaviour.
cancellationToken	System.Threading.CancellationToken	Optional. The cancellation token. It can only cancel UI prompts, once generation starts it must fail or conclude.

Returns

Type	Description
System.String[]	The array of generated asset paths. Null is returned in case user cancels UI prompts or generation errors are found.

Exceptions

ArgumentNullException:

scaffold is null.

ArgumentException:

targetPath is null.

-or-

targetPath is empty.

-or-

scaffold is invalid.

DirectoryNotFoundException:

targetPath's directory does not exist.

TemplManagers.ScaffoldManager.EnableScaffoldForSelection(Willykc.Templ.Editor.Scaffold.TemplScaffold)

Enables scaffold in settings for selection from the context menu.

Parameter	Type	Description
scaffold	Willykc.Templ.Editor.Scaffold.TemplScaffold	Required. The scaffold to enable for selection.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

ArgumentNullException:

scaffold is null.

ArgumentException:

scaffold is invalid.

TemplManagers.ScaffoldManager.DisableScaffoldForSelection(Willykc.Templ.Editor.Scaffold.TemplScaffold)

Disables scaffold in settings for selection from the context menu.

Parameter	Type	Description
scaffold	Willykc.Templ.Editor.Scaffold.TemplScaffold	Required. The scaffold to disable for selection.

Exceptions

InvalidOperationException:

TemplSettings does not exist.

ArgumentNullException:

scaffold is null.

class ScribanAsset

Namespace: Willykc.Templ.Editor

Extends: UnityEngine.ScriptableObject

Property	Type	Access	Description
Text	System.String	get;	Template text.
HasErrors	System.Boolean	get;	Template validity.
ParsingErrors	System.String[]	get;	Array of syntax errors.

class TemplEntry

Namespace: Willykc.Templ.Editor.Entry

Extends: System.Object

Property	Type	Access	Description
Id	System.String	get;	Unique entry id.
Template	ScribanAsset	get;	Entry template.
InputAsset	UnityEngine.Object	get;	Monitored asset.
OutputPath	System.String	get;	Path to the output asset.
IsValid	System.Boolean	get;	Entry validity.

class ScriptableObjectEntry

Field	Type	Description
scriptableObject	UnityEngine.ScriptableObject	The input scriptable object.

Namespace: Willykc.Templ.Editor.Entry

Extends: Willykc.Templ.Editor.Entry.TemplEntry

class AssemblyDefinitionEntry

Field	Type	Description
assembly	UnityEditorInternal.AssemblyDefinitionAsset	The input assembly definition.

Namespace: Willykc.Templ.Editor.Entry

Extends: Willykc.Templ.Editor.Entry.TemplEntry

class TemplScaffold

Namespace: Willykc.Templ.Editor.Scaffold

Extends: UnityEngine.ScriptableObject

Property	Type	Access	Description
DefaultInput	UnityEngine.ScriptableObject	get;	Default input instance.

class TemplDynamicScaffold

Namespace: Willykc.Templ.Editor.Scaffold

Extends: Willykc.Templ.Editor.Scaffold.TemplScaffold

Property	Type	Access	Description
TreeTemplate	Willykc.Templ.Editor.ScribanAsset	get;	Scaffold YAML tree template.

enum OverwriteOptions

Namespace: Willykc.Templ.Editor.Scaffold

Name	Value	Description
None	0	Show prompt for overwrites.
ShowPrompt	1	Show prompt for overwrites.
OverwriteAll	2	Overwrite all existing files.
SkipAll	3	Leave all existing files.

Coding guidelines

This repository follows these coding guidelines.

License

MIT