From Specification to Implementation

Bridging the gap between specifications and working code requires careful decomposition and systematic generation. This lesson covers workflows for turning specs into implementations.

The Specification Pipeline

Natural Language Spec → Structured Spec → Architecture → Components → Integration

Specification Structuring

From Prose to Structure

Identifying Ambiguities

async function findSpecAmbiguities(spec) {
  const prompt = `
Review this specification and identify ambiguities that need clarification.

SPECIFICATION:
${spec}

Look for:
1. Undefined terms
2. Unclear requirements
3. Missing edge cases
4. Conflicting requirements
5. Assumptions that should be explicit

Return:
{
  "ambiguities": [
    {
      "issue": "description of ambiguity",
      "location": "which part of spec",
      "question": "clarifying question to ask",
      "default_assumption": "what you'd assume if no answer"
    }
  ]
}
`;

  return await llm.chat({ content: prompt });
}

Architecture Generation

From Spec to Architecture

async function generateArchitecture(structuredSpec) {
  const prompt = `
Generate a system architecture based on this specification.

SPECIFICATION:
${JSON.stringify(structuredSpec, null, 2)}

Generate architecture including:
1. Component diagram (describe in text)
2. Data flow between components
3. External dependencies
4. API boundaries
5. Data storage requirements

Format:
{
  "components": [
    {
      "name": "",
      "responsibility": "",
      "interfaces": [],
      "dependencies": []
    }
  ],
  "data_flow": [],
  "external_services": [],
  "data_stores": []
}
`;

  return await llm.chat({ content: prompt });
}

Component Breakdown

Implementation Generation

Component-by-Component

async function generateComponents(architecture) {
  const implementations = [];

  // Sort by dependency order
  const sorted = topologicalSort(architecture.components);

  for (const component of sorted) {
    // Get already-generated dependencies
    const dependencies = implementations.filter(
      impl => component.dependencies.includes(impl.name)
    );

    const implementation = await generateComponent(component, dependencies);

    // Validate against interfaces
    const valid = await validateImplementation(implementation, component.interfaces);

    if (!valid.success) {
      // Retry with feedback
      implementation = await generateComponent(component, dependencies, valid.issues);
    }

    implementations.push(implementation);
  }

  return implementations;
}

Interface-First Generation

Integration Phase

Combining Components

async function integrateComponents(components) {
  // Step 1: Verify interfaces match
  const interfaceIssues = await verifyInterfaces(components);
  if (interfaceIssues.length > 0) {
    throw new Error(`Interface mismatches: ${interfaceIssues.join(', ')}`);
  }

  // Step 2: Generate integration code
  const integrationCode = await generateIntegration(components);

  // Step 3: Generate integration tests
  const integrationTests = await generateIntegrationTests(components, integrationCode);

  return {
    components,
    integration: integrationCode,
    tests: integrationTests
  };
}

Wiring Components

Validation Across the Pipeline

End-to-End Validation

async function validateImplementation(spec, implementation) {
  const validations = {
    // All operations from spec are implemented
    operationsCovered: checkOperationsCoverage(spec.operations, implementation),

    // All business rules are enforced
    rulesEnforced: checkBusinessRules(spec.business_rules, implementation),

    // All constraints are respected
    constraintsMet: checkConstraints(spec.constraints, implementation),

    // Integration points are correct
    integrationsValid: checkIntegrations(spec.integrations, implementation)
  };

  return {
    valid: Object.values(validations).every(v => v.passed),
    details: validations
  };
}

Exercise: Spec to Implementation Pipeline

Key Takeaways

• Structure natural language specs before generating code
• Identify and resolve ambiguities early
• Generate architecture before components
• Build components in dependency order
• Use interface-first generation for consistency
• Validate at each stage of the pipeline
• Integration is a distinct step requiring its own generation

Next, we'll cover test generation chains.