Shape Language

[!WARNING] Shape is currently alpha and experimental. Syntax, runtime behavior, APIs, module formats, and tooling may change between releases.

Shape is a statically typed, expression-oriented language for data transformation and simulation, with built-in support for checkpoint/resume and distributed continuation.

What Makes Shape Different

• Resumable + distributed workflows: checkpoint execution with snapshot(), resume deterministically, and hand continuation across workers through the transport/state stack.
• Unified metaprogramming model: comptime and annotations are one system, so compile-time generation, validation, and runtime policy wrappers compose cleanly.
• Polyglot functions in-source: write typed inline Python (and other runtimes) directly in Shape modules with automatic marshaling at the boundary.
• Data-native language surface: vectors, typed objects, and tables are core language types, not bolt-on libraries.
• Static types without verbosity: strong inference, expression-oriented control flow, traits/generics, and explicit Option/Result error semantics.

What Shape Looks Like

from std::core::snapshot use { Snapshot }

fn classify(values: Vec<number>) -> string {
  let avg = values.mean()
  if avg > 20.0 { "high" } else { "normal" }
}

let readings = [18.0, 22.0, 27.0, 19.0]
print(classify(readings))

match snapshot() {
  Snapshot::Hash(id) => {
    print("saved snapshot: " + id)
    exit(0)
  }
  Snapshot::Resumed => {
    print("resumed")
  }
}

Language Capabilities

• Core language: functions, lambdas, traits, generics, enums, pattern matching, references/borrowing
• Type and error model: inference-first static typing, structural object typing, Option/Result, typed propagation (?, !!)
• Expression-first semantics: if, match, and blocks return values, enabling compact pipeline-style code
• Comptime + annotations: compile-time hooks, runtime hooks, generated APIs, policy wrappers, and contract validation
• Concurrency and control: async/await, scoped joins, await annotations for orchestration policies
• Resumability and distribution: snapshot/resume, continuation handoff, state serialization, transport/wire primitives
• Modules and packaging: modules, packages, lockfiles, content-addressed bytecode, signed distribution paths
• Interop: native extensions, C interop, polyglot functions, Python extension runtime

Polyglot Example

Shape supports inline foreign-language functions via extensions. Example (fn python ...) from the book syntax:

fn python std_dev(values: Vec<number>) -> number {
  import math
  mean = sum(values) / len(values)
  variance = sum((x - mean) ** 2 for x in values) / len(values)
  return math.sqrt(variance)
}

let sigma = std_dev([4.0, 7.0, 13.0, 2.0, 1.0])
print(sigma)

Try It Quickly

Build workspace:

cargo build --workspace

Run REPL:

cargo run -p shape-cli --bin shape

Run a script:

cargo run -p shape-cli --bin shape -- path/to/script.shape

Cross-compile CLI release artifacts (for example CI on amd64 producing arm64 binaries):

cargo install cross --locked
cross build --release -p shape-cli --bin shape --target x86_64-unknown-linux-gnu
cross build --release -p shape-cli --bin shape --target aarch64-unknown-linux-gnu

Learn Shape

The canonical reference is the Shape Book: https://book.shape-lang.dev

Monorepo Layout

• crates/: language, runtime, wire, tooling, and visualization crates
• bin/: user-facing binaries (shape-cli)
• tools/: developer tooling (shape-lsp, shape-test, xtask)
• extensions/: native/runtime extension crates
• docs/: design docs, audits, and architecture notes
• tree-sitter-shape/: parser grammar and editor integration assets

License

Dual-licensed under MIT OR Apache-2.0, unless a crate states otherwise.

lib.rs:

Core value types for Shape

This crate contains the foundational value types and core data structures used throughout the Shape language implementation. The canonical runtime representation is ValueWord — an 8-byte NaN-boxed value.

Dependency hierarchy:

• shape-value → shape-ast (no circular dependencies)
• shape-runtime → shape-value (for types)
• shape-vm → shape-value (for types)