Regulatory Engine

The regulatory module implements a visual, graph-based rules engine for evaluating building regulations. Rules are created in the admin panel using a ReactFlow node graph editor and evaluated on the backend.

Concepts

Rules

A RegulatoryRule represents a single regulation or by-law. Each rule contains:

• Parameters — Input variables required and output variables produced
• Graph — A ReactFlow node/edge graph that defines the computation logic
• Metadata — Authority, region, regulatory reference, tags

Variables

A RegulatoryVariable is a globally-registered input or output parameter:

site.area          → number (sqm)     [INPUT]
site.road_width    → number (m)       [INPUT]
result.max_far     → number           [OUTPUT]
result.max_height  → number (m)       [OUTPUT]
result.setback.front → number (m)     [OUTPUT]

Graph Evaluation

The rule graph is a DAG (directed acyclic graph) of computation nodes:

┌───────────┐     ┌──────────────┐     ┌────────────┐
│ Input:    │────▶│ Condition:   │────▶│ Output:    │
│ site.area │     │ area > 2000  │     │ max_far    │
└───────────┘     │   ? 2.5      │     │ = result   │
                  │   : 1.75     │     └────────────┘
                  └──────────────┘

Node types include:

• Input — Reads a variable value
• Constant — Fixed numeric/boolean/string value
• Comparison — >, <, >=, <=, ==, !=
• Arithmetic — +, -, *, /
• Conditional — If/then/else branching
• Output — Writes a result variable
• Math Functions — min, max, round, ceil, floor

Endpoints

Method	Path	Description
GET	/regulatory/rules	List all rules
POST	/regulatory/rules	Create a new rule
GET	/regulatory/rules/:id	Get rule details (including graph)
PATCH	/regulatory/rules/:id	Update a rule
DELETE	/regulatory/rules/:id	Delete a rule
POST	/regulatory/rules/:id/evaluate	Evaluate a rule with given inputs
GET	/regulatory/variables	List all registered variables
POST	/regulatory/variables	Register a new variable
DELETE	/regulatory/variables/:key	Delete a variable

Evaluation

To evaluate a rule:

// POST /regulatory/rules/RUL-001/evaluate
{
  "inputs": {
    "site.area": 4000,
    "site.road_width": 12,
    "site.zone": "residential"
  }
}

// Response
{
  "outputs": {
    "result.max_far": 2.5,
    "result.max_height": 24,
    "result.setback.front": 3,
    "result.setback.rear": 2
  }
}

The backend traverses the rule graph using math.js for expression evaluation, resolving node dependencies in topological order.