Extending Backends

Create custom code generators by extending InkGen’s backend architecture.

Backend Structure

A backend is a module that implements the Backend interface:

export interface Backend {
  name: string;
  generate(ir: IntermediateRepresentation): GeneratedCode[];
  validate(): ValidationResult;
}

Creating a Custom Backend

1. Implement the Backend Interface

import { Backend, IntermediateRepresentation } from '@octofhir/inkgen';

export class MyBackend implements Backend {
  name = 'mybackend';

  generate(ir: IntermediateRepresentation) {
    // Your generation logic
    return [];
  }

  validate() {
    return { valid: true };
  }
}

2. Register the Backend

import { registerBackend } from '@octofhir/inkgen';
import { MyBackend } from './my-backend';

registerBackend(new MyBackend());

3. Use in Configuration

{
  "backends": ["mybackend"]
}

Example: Python Backend

Create a simple Python backend:

export class PythonBackend implements Backend {
  name = 'python';

  generate(ir: IntermediateRepresentation) {
    return ir.profiles.map(profile => ({
      path: `${profile.name}.py`,
      content: `
class ${profile.name}:
    def __init__(self):
        pass
`
    }));
  }

  validate() {
    return { valid: true };
  }
}

Best Practices

1. Handle all FHIR types - Support all types in the IR
2. Generate idiomatic code - Follow language conventions
3. Include validation - Add runtime type checking
4. Document output - Generate comments explaining types
5. Test thoroughly - Validate against sample data

For more details on the IR structure, see IR Design.