typdd-dev

typdd-dev

Develop the typdd Typst library — a BDD visualization package built on fletcher.

Architecture

Pipeline: parse → build → reduce → layout → render

File	Role	Key functions
lib.typ	Public API, adaptive spacing	bdd(), bdd-from-json()
src/parse.typ	Tokenizer + recursive descent parser	tokenize(), parse(), collect-vars()
src/bdd.typ	Shannon expansion, unique table, reduction	build-bdd(), build(), reduce(), substitute()
src/layout.typ	Sugiyama-inspired layered layout	assign-positions()
src/render.typ	Fletcher diagram generation	render-bdd() (uses node(), edge())
src/styles.typ	Visual presets + shared layout constants	get-style(), merge-style(), _shared-layout
src/order.typ	Variable ordering heuristics	dfs-order(), weight-order(), force-order()
src/abstract.typ	Subtree collapsing, stats	collapse-subtrees(), bdd-stats()
src/import.typ	JSON interchange import	import-json()

MCP server (typdd-mcp/): TypeScript mirror of parser/BDD engine with tools/prompts.

Recipes

Task	Files to touch
New operator	src/parse.typ (tokenizer + grammar) → src/bdd.typ (evaluate + substitute) → tests/parse/test.typ + tests/bdd/test.typ
New style	src/styles.typ (spread _shared-layout, colors/strokes only) → get-style() match → examples/styles.typ
Layout fix	src/layout.typ (barycenter, overlap resolution, centering)
Render change	src/render.typ (fletcher node()/edge(), stroke/fill/bend)
New API param	lib.typ (add to bdd() sig + _render-pipeline())
JSON import	src/import.typ → tests/integration/test.typ

Data Structures

AST nodes (from parser):

(kind: "var", name: "x1")
(kind: "const", value: true/false)
(kind: "not", child: ast)
(kind: "binop", op: "&"|"|"|"^"|"=>"|"~&"|"~|"|"~^", left: ast, right: ast)
(kind: "ite", cond: ast, then-branch: ast, else-branch: ast)

BDD structure: (nodes: array, root: int, order: array) where each node is (id: int, kind: "terminal", value: bool) or (id: int, kind: "variable", var: str, low: int, high: int).

Unique table key: "var:low-id:high-id" — ensures canonical BDD nodes.

Test

make test       # 4 Typst (tytanic) + MCP (bun test)
make typst      # Typst tests only: tt run
make mcp        # MCP tests only: cd typdd-mcp && bun test
make examples   # Rebuild PNGs

Tests are compile-time asserts — if any #assert.eq(...) fails, compilation exits non-zero. BDD correctness is verified via truth-table oracle (enumerate all 2^n assignments).

Rules

• Styles: colors/strokes only, never layout dims (those live in _shared-layout)
• Typst conventions: kebab-case, /// doc comments, absolute imports (/src/...)
• AST keys: then-branch/else-branch (not then/else)
• State threading: parser and builder return (result: ..., pos: ...) / (node-id: ..., nodes: ..., next-id: ..., unique-table: ...)
• No forward declarations: parser uses single _parse(tokens, pos, level) with level parameter to select grammar rule
• Grammar precedence (low→high): => → |/~| → ^/~^ → &/~& → !