Authoring a LionWeb Language in C#

This guide demonstrates how to define and serialize a LionWeb language dynamically using the LionWeb-CSharp library.

Overview

In this example, we define a simple language called Complaints Language with the following components:

• A language entity
• A Complaints Book concept that contains complaints
• A Complaint concept with properties:
  • Date (optional)
  • Description (required)
  • Urgent flag (required boolean)
• A Date primitive type
• The serialization of the language into a JSON file using LionWeb v2024_1

Required Namespaces

using System.Text.Json;
using System.Text.Json.Serialization;
using LionWeb.Core;
using LionWeb.Core.M1;
using LionWeb.Core.M3;
using LionWeb.Core.VersionSpecific.V2024_1;

Defining the Language

var language = new DynamicLanguage("lang", LionWebVersions.v2024_1)
{
    Key = "key-lang", 
    Version = "0",
    Name = "ComplaintsLanguage",
};

Defining Concepts

Complaints Book Concept

var complaintsBook = new DynamicConcept("complaints-book", LionWebVersions.v2024_1, language)
{
    Partition = true,
    Key = "complaints-book",
    Name = "ComplaintsBook",
};

Complaint Concept

var complaint = new DynamicConcept("complaint", LionWebVersions.v2024_1, language)
{
    Key = "complaint",
    Name = "Complaint",
};

Date Primitive Type

var date = new DynamicPrimitiveType("date", LionWebVersions.v2024_1, language)
{
    Key = "date",
    Name = "Date"
};

Add all entities to the language:

language.AddEntities([complaintsBook, complaint, date]);

Defining Features

Containment: Book → Complaints

var bookComplaints = new DynamicContainment("complaints-book-complaints", LionWebVersions.v2024_1, complaintsBook)
{
    Key = "complaints-book-complaints",
    Name = "Complaints",
    Optional = false,
    Multiple = true,
    Type = complaint
};
complaintsBook.AddFeatures([bookComplaints]);

Properties of Complaint

var complaintDate = new DynamicProperty("complaint-date", LionWebVersions.v2024_1, complaint)
{
    Key = "complaint-date",
    Name = "Date",
    Optional = true,    
    Type = date
};

var complaintDescription = new DynamicProperty("complaint-description", LionWebVersions.v2024_1, complaint)
{
    Key = "complaint-description",
    Name = "Description",
    Optional = false,
    Type = BuiltInsLanguage_2024_1.Instance.String,
};

var complaintUrgent = new DynamicProperty("complaint-urgent", LionWebVersions.v2024_1, complaint)
{
    Type = BuiltInsLanguage_2024_1.Instance.Boolean,
    Key = "complaint-urgent",
    Name = "Urgent?",
    Optional = false,
};

complaint.AddFeatures([complaintDate, complaintDescription, complaintUrgent]);

Serializing to JSON

Serialize the Language

var serializationChunk = new SerializerBuilder()
    .WithLionWebVersion(LionWebVersions.v2024_1)
    .Build()
    .SerializeToChunk([language]);

Save to File

var options = new JsonSerializerOptions
{
    WriteIndented = true,
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
};

var filePath = "ComplaintsLanguage.json";
File.WriteAllText(filePath, JsonSerializer.Serialize(serializationChunk, options));
Console.WriteLine($"Serialized JSON saved to: {Path.GetFullPath(filePath)}");

Output

This script creates a file called ComplaintsLanguage.json that contains the LionWeb serialization of your custom language.

You can then load it, inspect it, or serve it in a modeling tool that understands LionWeb.

The complete example

using System.Text.Json;
using System.Text.Json.Serialization;
using LionWeb.Core;
using LionWeb.Core.M1;
using LionWeb.Core.M3;
using LionWeb.Core.VersionSpecific.V2024_1;

var language = new DynamicLanguage("lang", LionWebVersions.v2024_1)
{
    Key = "key-lang", 
    Version = "0",
    Name = "ComplaintsLanguage",
};
var complaintsBook = new DynamicConcept("complaints-book", LionWebVersions.v2024_1, language)
{
    Partition = true,
    Key = "complaints-book",
    Name = "ComplaintsBook",
};
var complaint = new DynamicConcept("complaint", LionWebVersions.v2024_1, language)
{
    Key = "complaint",
    Name = "Complaint",
};
var date = new DynamicPrimitiveType("date", LionWebVersions.v2024_1, language)
{
    Key = "date",
    Name = "Date"
};
language.AddEntities([complaintsBook, complaint, date]);

var bookComplaints = new DynamicContainment("complaints-book-complaints", LionWebVersions.v2024_1, complaintsBook)
{
    Key = "complaints-book-complaints",
    Name = "Complaints",
    Optional = false,
    Multiple = true,
    Type = complaint
};
complaintsBook.AddFeatures([bookComplaints]);

var complaintDate = new DynamicProperty("complaint-date", LionWebVersions.v2024_1, complaint)
{
    Key = "complaint-date",
    Name = "Date",
    Optional = true,    
    Type = date
};
var complaintDescription = new DynamicProperty("complaint-description", LionWebVersions.v2024_1, complaint)
{
    Key = "complaint-description",
    Name = "Description",
    Optional = false,
    Type = BuiltInsLanguage_2024_1.Instance.String,
};
var complaintUrgent = new DynamicProperty("complaint-urgent", LionWebVersions.v2024_1, complaint)
{
    Type = BuiltInsLanguage_2024_1.Instance.Boolean,
    Key = "complaint-urgent",
    Name = "Urgent?",
    Optional = false,
};
complaint.AddFeatures([complaintDate, complaintDescription, complaintUrgent]);

var serializationChunk = new SerializerBuilder().WithLionWebVersion(LionWebVersions.v2024_1).Build()
    .SerializeToChunk([language]);

var options = new JsonSerializerOptions
{
    WriteIndented = true,
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
};

var filePath = "ComplaintsLanguage.json";
File.WriteAllText(filePath, JsonSerializer.Serialize(serializationChunk, options));

Console.WriteLine($"Serialized JSON saved to: {Path.GetFullPath(filePath)}");