Language Overview¶

MOL is a statically-scoped, dynamically-typed programming language built for cognitive computing and AI pipeline development.

Design Principles¶

1. Pipelines are first-class — The |> operator is a core language feature, not a library
2. Visibility by default — Auto-tracing means you never fly blind
3. Domain-aware types — AI concepts are language primitives, not dicts
4. Safety built-in — Guards and access control at the language level
5. Universal utility — Algorithms and data structures everyone needs
6. Write once, run anywhere — Transpile to Python or JavaScript

Architecture¶

graph LR
    A[".mol source"] --> B["LALR Parser<br/>(Lark)"]
    B --> C["AST<br/>(28 node types)"]
    C --> D["Interpreter"]
    C --> E["Python Transpiler"]
    C --> F["JS Transpiler"]
    D --> G["Output + Trace"]
    E --> H[".py file"]
    F --> I[".js file"]

File Extension¶

All MOL source files use the .mol extension.

Comments¶

-- This is a comment (double dash)
-- MOL uses Lua/Haskell-style comments

Program Structure¶

A MOL program is a sequence of statements executed top-to-bottom:

-- 1. Declarations
let name be "MOL"
let version be 0.2

-- 2. Functions
fn greet(who)
  return "Hello, " + who
end

-- 3. Logic
if version > 0.1 then
  show greet(name)
end

Keywords (30)¶

Operators¶

Type System¶

MOL is dynamically typed with 12 built-in types:

Optional type annotations:

let x: Number be 42        -- passes
let y: Text be 42          -- MOLTypeError!