Functions, Bindings, And Annotations

Current implementation evidence: examples/pure-capability.0x0,

docs/language.html, and docs/documentation.html.

Function Shape

Functions use ƒ:

(ƒ add
  (∷ (→ I64 I64 I64))
  (cap pure)
  (doc "Return the sum of two integers without effects.")
  (a b)
  (+ a b))

The parameter list appears after annotations. The function body follows the

parameter list.

Type Annotations

∷ carries the current checked source contract:

(∷ (→ I64 I64 I64))

The current checker validates the implemented slice:

• arrow form uses →;
• annotation arity matches parameter count when the return type is concrete;
• typed 0x0 function calls use declared arity;
• simple I64, Text, Bool, and Unit mismatches are rejected when inferred.

This is not a complete type system. Complex unresolved cases remain permissive.

Documentation Annotations

doc annotations describe public functions:

(doc "Return the sum of two integers without effects.")

The compiler parses and skips doc annotations for output behavior. The API

documentation generator reads them for public docs.

Bindings

Use ≔ for local names:

(≔ ((sum (+ 20 22)))
  sum)

The compiler validates that local symbols resolve to parameters or earlier

bindings.

Practical Habit

Write public functions with type, capability, and doc annotations when the

function belongs to a library or framework. Keep local helpers documented when

their representation choices are not obvious.