FlowOn Language (FoL)

All FlowOn artifacts are expressed in FlowOn Language (FoL)—a declarative, JSON-based domain-specific language designed to capture business requirements in an executable format.

Design Principles

Principle	Description
Declarative	Describe what, not how
Intuitive	Natural to business concepts
Portable	JSON format, version-controllable
Executable	Directly runnable without compilation
Expressive	Rich enough for complex problems
Extensible	New constructs can be added

Language Coverage

FoL can express:

• Calculations: Formulas, expressions, transformations
• Decisions: Rules, conditions, branching logic
• Validations: Constraints, checks, error messages
• Processes: Workflows, stages, transitions
• Integrations: API calls, data mappings
• Events: Triggers, handlers, subscriptions

Toward Turing Completeness

Our objective is to make FoL Turing complete—capable of expressing any computation. Current capabilities include:

• ✅ Variables and assignments
• ✅ Conditional logic (if/then/else)
• ✅ Loops and iterations
• ✅ Functions and composition
• ✅ Recursion (via flows)
• ✅ State management

Examples

Formula

{
  "name": "CalculateOrderTotal",
  "type": "Formula",
  "inputs": [
    { "name": "Subtotal", "type": "Decimal" },
    { "name": "TaxRate", "type": "Decimal" },
    { "name": "DiscountAmount", "type": "Decimal" }
  ],
  "output": { "type": "Decimal" },
  "expression": "Subtract(Add(Subtotal, Multiply(Subtotal, TaxRate)), DiscountAmount)"
}

Decision Table

{
  "name": "DiscountRates",
  "type": "DecisionTable",
  "hitPolicy": "First",
  "conditions": [
    { "name": "Quantity", "type": "Integer" },
    { "name": "CustomerTier", "type": "String" }
  ],
  "actions": [
    { "name": "DiscountPercent", "type": "Decimal" }
  ],
  "rules": [
    { "conditions": [">= 100", "Gold"], "actions": ["0.20"] },
    { "conditions": [">= 100", "Silver"], "actions": ["0.15"] },
    { "conditions": [">= 50", "Gold"], "actions": ["0.10"] },
    { "conditions": ["*", "*"], "actions": ["0.00"] }
  ]
}

Validation

{
  "name": "ValidateEmail",
  "type": "Validation",
  "condition": "MatchPattern(Email, '^[a-z]+@[a-z]+\\.[a-z]+$')",
  "errorMessage": "Invalid email format",
  "severity": "Error"
}

Logic Flow

{
  "name": "ProcessOrder",
  "type": "LogicFlow",
  "steps": [
    {
      "name": "ValidateOrder",
      "type": "RunValidationSet",
      "validationSet": "OrderValidations"
    },
    {
      "name": "CalculateTotal",
      "type": "RunLogicBlock",
      "logicBlock": "CalculateOrderTotal",
      "outputVariable": "Total"
    },
    {
      "name": "CheckApproval",
      "type": "Condition",
      "condition": "IsGreaterThan(Total, 10000)",
      "trueSteps": ["RequireApproval"],
      "falseSteps": ["AutoApprove"]
    }
  ]
}

Requirements-as-Code in Action

┌─────────────────────────────────────────────────────────────────────┐
│                    FLOWON ARTIFACTS = REQUIREMENTS                  │
├─────────────────────────────────────────────────────────────────────┤
│                                                                     │
│   TRADITIONAL                          FLOWON                       │
│   ───────────                          ──────                       │
│                                                                     │
│   "The system shall calculate         ┌─────────────────────────┐   │
│    the order total as the sum         │ Formula: OrderTotal     │   │
│    of line item amounts plus          │                         │   │
│    shipping minus any discount"       │ Sum(LineItems.Amount)   │   │
│                                       │ + ShippingCost          │   │
│   ↓                                   │ - DiscountAmount        │   │
│                                       │                         │   │
│   Developer interprets...             │ ← THIS IS THE           │   │
│   Developer writes C#...              │   REQUIREMENT AND THE   │   │
│   Tester writes tests...              │   IMPLEMENTATION        │   │
│   Documentation outdated...           └─────────────────────────┘   │
│                                                                     │
└─────────────────────────────────────────────────────────────────────┘