| name | typdd-dev |
| description | Use when modifying typdd library source code, adding operators or styles, fixing layout or rendering, writing tests, or debugging BDD construction. |
| argument-hint | <what to add, fix, or change> |
| allowed-tools | ["Read","Write","Edit","Bash","Glob","Grep"] |
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
make typst
make mcp
make examples
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):
=> → |/~| → ^/~^ → &/~& → !
