scriban

Scriban is a fast, powerful, safe and lightweight scripting language and engine for .NET, which was primarily developed for text templating with a compatibility mode for parsing liquid templates.

Today, not only Scriban can be used in text templating scenarios, but also can be integrated as a general scripting engine: For example, Scriban is at the core of the scripting engine for kalk, a command line calculator application for developers.

// Parse a scriban template
var template = Template.Parse("Hello {{name}}!");
var result = template.Render(new { Name = "World" }); // => "Hello World!" 

Parse a Liquid template using the Liquid language:

// Parse a liquid template
var template = Template.ParseLiquid("Hello {{name}}!");
var result = template.Render(new { Name = "World" }); // => "Hello World!" 

The language is very versatile, easy to read and use, similar to liquid templates:

var template = Template.Parse(@"
<ul id='products'>
  {{ for product in products }}
    <li>
      <h2>{{ product.name }}</h2>
           Price: {{ product.price }}
           {{ product.description | string.truncate 15 }}
    </li>
  {{ end }}
</ul>
");
var result = template.Render(new { Products = this.ProductList });

Scriban can also be used in pure scripting context without templating ({{ and }}) and can help you to create your own small DSL.

NOTICE

By default, Properties and methods of .NET objects are automatically exposed with lowercase and _ names. It means that a property like MyMethodIsNice will be exposed as my_method_is_nice. This is the default convention, originally to match the behavior of liquid templates. If you want to change this behavior, you need to use a MemberRenamer delegate

New in 3.0+

• AST is now fully visitable with ScriptVisitor. You can now access Parent on any ScriptNode object and navigate the AST.
  • Improve AST round-trip by preserving whitespaces around template enter{{ and exit}}
• Several new language features:
  • Hexadecimal/binary numbers: 0x1ef or 0b101010
  • Support for large integers
  • New parametric functions: func sub(x,y = 1, z...); ret x - y - z[0]; end
  • New inline functions: sub(x,y) = x - y
  • Optional member access with ?. instead of regular . (e.g a?.b?.c)
  • Conditional expressions: cond ? a : b
• Separate language mode (via ScriptLang enum) from template/scripting parsing mode (ScriptMode).
• New language parsing mode Scientific, in addition to default Scriban and Liquid language mode.
• More fine-grained options on the TemplateContext to define scripting behaviors (EnableRelaxedTargetAccess, EnableRelaxedMemberAccess, EnableRelaxedFunctionAccess, EnableRelaxedIndexerAccess, EnableNullIndexer)
• New object.eval and object.eval_template function to evaluate Scriban expressions/templates at runtime.
• Better support for IFormattable objects.

Features

• An extensible sandbox execution model: You have the full control about which Scripting objects (and so properties and methods) are accessible from Scriban templates.
• Very efficient, fast parser and a lightweight runtime. CPU and Garbage Collector friendly.
• Powered by a Lexer/Parser providing a full Abstract Syntax Tree, fast, versatile and robust, more efficient than regex based parsers.
  • Precise source code location (path, column and line) for error reporting
  • Write an AST to a script textual representation, with Template.ToText, allowing to manipulate scripts in memory and re-save them to the disk, useful for roundtrip script update scenarios
• Compatible with liquid by using the Template.ParseLiquid method
  • While the liquid language is less powerful than scriban, this mode allows to migrate from liquid to scriban language easily
  • With the AST to text mode, you can convert a liquid script to a scriban script using Template.ToText on a template parsed with Template.ParseLiquid
  • As the liquid language is not strictly defined and there are in fact various versions of liquid syntax, there are restrictions while using liquid templates with scriban, see the document liquid support in scriban for more details.
• Extensible runtime providing many extensibility points
• Support for async/await evaluation of scripts (e.g Template.RenderAsync)
• Precise control of whitespace text output
• Full featured language including if/else/for/while, expressions (x = 1 + 2), conditions... etc.
• Function calls and pipes (myvar | string.capitalize)
  • Custom functions directly into the language via func statement and allow function pointers/delegates via the alias @ directive
  • Bind .NET custom functions from the runtime API with many options for interfacing with .NET objects.
• Complex objects (javascript/json like objects x = {mymember: 1}) and arrays (e.g x = [1,2,3,4])
• Allow to pass a block of statements to a function, typically used by the wrap statement
• Several built-in functions:
  • arrays functions
  • date
  • html
  • maths functions
  • object
  • regex functions
  • string functions
  • timespan
• Multi-line statements without having to embrace each line by {{...}}
• Safe parser and safe runtime, allowing you to control what objects and functions are exposed

Syntax Coloring

You can install the Scriban Extension for Visual Studio Code to get syntax coloring for scriban scripts (without HTML) and scriban html files.

Documentation

• See the Language document for a description of the language syntax.
• See the Built-in functions document for the list of the built-in functions.
• See the Runtime document for a description of the .NET runtime API to compile and run templates.
• See the Liquid support document for more details about the support of liquid templates.
• See my blog post "Implementing a Text Templating Engine for .NET" for some behind the scene details.

Binaries

Scriban is available as a NuGet package:

Compatible with the following .NET Standard 2.0+ (New in 3.0)

For support for older framework (.NET 3.5, 4.0, 4.5, .NET Standard 1.1, 1.3, they are only provided in older Scriban 2.x, which is no longer supported.

Also the Scriban.Signed NuGet package provides signed assemblies.

Source Embedding

Starting with Scriban 3.2.1+, the package comes with source included so that you can internalize your usage of Scriban into your project. This can be useful in an environment where you can't easily consume NuGet references (e.g Roslyn Source Generators).

WARNING: Currently, the Scriban sources are not set as readonly, so you should not modify Scriban sources in that mode as it will modify the sources for other projects using Scriban on your machine. Use this feature at your own risks!

In order to activate this feature you need to:

• Set the property PackageScribanIncludeSource to true in your project:

  <PropertyGroup>
  <PackageScribanIncludeSource>true</PackageScribanIncludeSource>
  </PropertyGroup>

• Add the IncludeAssets="Build" to the NuGet PackageReference for Scriban:

  <ItemGroup>
  <PackageReference Include="Scriban" Version="3.2.1" IncludeAssets="Build"/>
  </ItemGroup>

If you are targeting netstandard2.0 or .NET Framework 4.7.2+, in order to compile Scriban you will need these NuGet package references (that can come from a dependency that you already have):

<ItemGroup>
    <PackageReference Include="Microsoft.CSharp" Version="4.5.0" />
    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.0" />
</ItemGroup>

NOTE: In this mode, all Scriban types are marked as internal.

You should see a Scriban folder and empty subfolders in your project. This is an issue with Visual Studio 2019 16.8.x (and before) and it will be fixed in VS 2019 16.9+

License

This software is released under the BSD-Clause 2 license.

Related projects

• dotliquid: .NET port of the liquid templating engine
• Fluid .NET liquid templating engine
• Nustache: Logic-less templates for .NET
• Handlebars.Net: .NET port of handlebars.js
• Textrude: UI and CLI tools to turn CSV/JSON/YAML models into code using Scriban templates
• NTypewriter: VS extension to turn C# code into documentation/TypeScript/anything using Scriban templates

Online Demo

• (https://scribanonline.azurewebsites.net/): ASP.NET Core Sample.

Credits

Adapted logo Puzzle by Andrew Doane from the Noun Project

Author

Alexandre Mutel aka xoofx.