Sheet

Sheet-lang is a typed dataflow language for node sheets. A sheet is a graph of nodes; each node holds a formula (Excel-style functions on typed values) or a small program, and the nodes' outputs feed other nodes' inputs. Sheet-lang checks types and units, runs the graph incrementally, and keeps going when part of the input is not known yet.

Status: experimental. The syntax, the IR and the stored workspace format may change without notice. All crates are publish = false for now.

input 売上: Table<地域: Text, 金額: Int>
let 東 = query {
  from 行 in 売上
  where 行.地域 = "東"
}
output n = ROWS(東)

fn factorial(n: Int) -> Int { if n <= 1 { 1 } else { n * factorial(n - 1) } }
factorial(10)

Features

• Excel-compatible built-ins (SUM, MAP, REDUCE, dates, text, lookup, statistics, finance) next to ordinary fn, let, var, while and for.
• Static types with units, decimals, vectors, tables and relations; query blocks over tables.
• Algebraic effects (effect, perform, handle … with) for errors, inputs and requests.
• Holes: a value that is not known yet (?x) is carried through, so a run reports what it could compute and what it still waits for.
• Rules and search: logic { … } with objectives, evaluated by derive or solve.
• Incremental, budgeted and cancellable evaluation.

Crates

Crate	Role
sheet-lang-parol	grammar (sheet.par), generated parser, syntax tree and syntax errors
sheet-lang-model	types, units, decimals, values, IR, stable ids, node graph and workspace
sheet-lang-compiler	incremental compiler on query-flow: name resolution, type checking, lowering, editor services
sheet-lang-runtime	IR interpreter, standard library, incremental and cancellable evaluation on whale
sheet-lang-test-suite	Eure case files that specify what the parser, checker, evaluator and editor services answer

Build and test

The toolchain is pinned in rust-toolchain.toml (a nightly; rustup installs it on first use).

cargo test --locked --workspace
cargo test -p sheet-lang-test-suite --test cases -- <filter>   # run matching cases
cargo clippy --workspace --all-targets --locked -- -D warnings

The behaviour of the language is specified by the case files under crates/sheet-lang-test-suite/cases/ (syntax, types, eval, editor). To add a behaviour, add a case there.

Parser generation

The parser is generated from crates/sheet-lang-parol/sheet.par by parol and committed under crates/sheet-lang-parol/src/generated/. parol runs only in tools/sheet-lang-parol-gen, a workspace of its own with its own lockfile.

bash scripts/generate-sheet-lang-parol.sh          # regenerate
bash scripts/generate-sheet-lang-parol.sh --check  # fail if the committed files are stale

Supply chain

• .cargo/config.toml refuses crate versions published less than 14 days ago (enforced by the nightly Cargo pinned in rust-toolchain.toml).
• .gitignore is an allowlist: everything is ignored unless allowed. Check it when you add a new kind of file.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this work, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.