AiACodeGenerator 1.0.6

CodeGen

CodeGen is a powerful, flexible C# and XAML source code generation tool driven by YAML/JSON configuration files. It is designed around Domain-Driven Design (DDD) principles and uses Microsoft Roslyn for safe, AST-based code manipulation and Scriban for rich templating.

Features

• YAML/JSON Driven: Define your features, screens, and data models in simple YAML or JSON files.
• Scriban Templates: Uses the robust Scriban engine for rendering C# and XAML templates. Supports custom filters (pascal_case, camel_case, snake_case) and {{ include }} directives.
• Roslyn AST Manipulation: Safely insert statements into existing methods or add/overwrite properties and methods in existing C# classes without breaking formatting.
• XAML Marker Insertion: Intelligently insert XAML snippets into existing files using comment markers.
• Flexible Path Templating: Output paths support dynamic tokens like {{feature.name}}, {{feature.name.camel}}, {{screen.name}}, and any custom data variables.
• Shared vs Screen Files: Generate files that belong to the entire feature (e.g., Utils, Models) or files specific to individual screens (e.g., ViewModels, Pages).

Architecture

Built with modern C# 10+ standards, the tool follows Clean Architecture and DDD:

• Domain: Pure logic, Aggregates (Feature, Screen, FileAction), Value Objects (FeatureName), and domain abstractions.
• Application: Vertical Slices containing Use Cases (e.g., GenerateFeatureHandler).
• Infrastructure: Implementations of config parsing (YamlDotNet), templating (Scriban), Roslyn editors, and I/O.
• Console: A lightweight CLI entry point built with Microsoft.Extensions.Hosting.

CLI Usage

Run the tool using the .NET CLI:

dotnet run --project src/CodeGen.Console -- --config <path_to_yaml> [options]

Options

Example Command

dotnet run --project src/CodeGen.Console -- -c ./configs/features/user_management.yaml -o ./output

Configuration Schema

A feature configuration file describes the code generation pipeline. It defines shared files and screen-specific files.

Example: user_management.yaml

feature:
  name: "UserManagement"
  namespace: "MyApp.Features.UserManagement"

  # ─── FEATURE-LEVEL FILES (shared across all screens) ─────────────────────────
  files:
    - action: create_class
      output: "Features/{{feature.name}}/Utils/{{feature.name}}Helper.cs"
      template: "csharp/utility_class.sbn"
      data:
        class_name: "UserManagementHelper"

  # ─── SCREEN-LEVEL FILES ───────────────────────────────────────────────────────
  screens:
    - name: "UserListScreen"
      files:
        - action: create_class
          output: "Features/{{feature.name}}/ViewModels/UserListViewModel.cs"
          template: "csharp/viewmodel.sbn"
          data:
            class_name: "UserListViewModel"
            base_class: "ObservableObject"
            controls:
              - name: "UserName"
                type: "string"
              - name: "Role"
                type: "string"

Action Types

The action field in a file definition dictates how the processor handles the file:

1. create_class: Renders a .sbn template and writes it to the output path. Overwrites if the file exists.
2. create_xaml: Similar to create_class, but used for XAML generation.
3. insert_method: Uses Roslyn to add a new method/property to an existing C# class defined in target. Overwrites if a member with the same name exists. Requires data.insert_in_class or position.in_class.
4. insert_code: Uses Roslyn to safely insert a statement inside the body of an existing method. Requires position (InClass, InMethod).
5. insert_xaml: Inserts a rendered XAML snippet into an existing file using text-based comment markers. Requires position.

Positioning Types

When modifying existing files (insert_* actions), you can control exactly where the code goes using the position object:

Example: Roslyn Statement Insertion

- action: insert_code
  target: "Program.cs"
  template: "csharp/di_registration.sbn"
  position:
    type: "inside_method"
    in_class: "Program"
    in_method: "ConfigureServices"
    type: "after_marker" 
    marker: "// [CODEGEN:Services]"

Templating (Scriban)

Templates are stored in the folder configured via appsettings.yaml (default: ./templates).

Built-in Custom Filters

• {{ my_var | pascal_case }}: user_name → UserName
• {{ my_var | camel_case }}: UserName → userName
• {{ my_var | snake_case }}: UserName → user_name

Includes

You can break templates into partials and include them recursively (useful for XAML layout builders):

{{- include "xaml/" + (child.type | string.downcase) + ".sbn" child -}}

Global Configuration (appsettings.yaml)

codegen:
  templatesDir: "./templates"
  outputRoot: "./output"
  dryRun: false

(You can also use environment variables prefixed with CODEGEN_, e.g., CODEGEN_TemplatesDir)