Module node 

The content-addressed AST node model.

A node references its children by their content hash, so a node’s own hash covers the hashes of everything beneath it — the Merkle property the store relies on (docs/design.md Section 7). Two structurally identical subtrees therefore have the same hash and are stored once.

This is the v0.1 seed model. It now carries the Section 4 function contract (given/produces/requires/on_failure) so the checker can enforce it. A signature is part of a function’s identity, so Param/Produces are inlined into the Function node rather than being separate nodes. Record and variant definitions, generics, and operators are later slices.

Structs

MatchArm

One arm of a match: a variant case, names bound to its payload fields (in declaration order), and the body evaluated when that case matches.

NodeHash

A content hash: the lowercase hex SHA-256 of a node’s canonical bytes.

Param

One declared input: its name, type, and the minimum confidence a caller must supply (the given clause).

Produces

The produces clause: the output type and the confidence it carries.

Enums

BinOp

A binary operator. Arithmetic operands and result are Number; comparison operands share a type and the result is Bool; logical operands and result are Bool (short-circuit). Deliberately small (Principle 9): one canonical operator per operation.

Node

A stored AST node. Compound variants reference children by NodeHash.