Getting Started

Add the generator to the project, then mark the template methods partial.

<ItemGroup>
    <PackageReference Include="Cutout" Version="x.x.x">
        <PrivateAssets>all</PrivateAssets>
        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
</ItemGroup>

Use the Cutout.Template attribute to define a template method. The first parameter is the StringBuilder-like type to write to; everything else is available in the template.

using System.Text;

[Cutout.Template("A template with a {{parameter}} parameter")]
public static partial void Test(this StringBuilder builder, string parameter);

With parameter set to value the builder contains,

A template with a value parameter

The template has to be a compile-time constant, so define it as a const field or inline in the attribute.

private const string TemplateExample = """
    A multi-line template example
    with a {{parameter}} parameter.

    It also has a conditional section,
    {%- if parameter == "INVALID" %}
    show this text
    {%- else %}
    show this text instead
    {%- end %}
    """;

[Cutout.Template(TemplateExample)]
public static partial void Test(this StringBuilder builder, string parameter);

With parameter set to value that renders,

A multi-line template example
with a value parameter.

It also has a conditional section,
show this text instead

What the generator does not accept

• The template method must be partial; the generator fills in the body
• The template must be a constant string, not a string built at runtime
• The first parameter must be a StringBuilder-like type; the generator writes the rendered output into it
• Templates come from the attribute. The generator does not read template files from other projects