jacquard

Jacquard Standalone Guide

Jacquard is a research language for model-written, human-reviewed programs. Its central promise is that effects, uncertainty, and program identity remain visible to the checker and tools:

• Function arrows carry effect rows, such as (Text) ->{Net, Console} Int.
• A runnable expression's inferred row is its authority manifest. The runtime installs world handlers only for explicit --allow grants.
• Probability is the ordinary Dist effect. Exact enumeration and likelihood weighting run the same model under different handlers.
• Definitions are content-addressed from canonical resolved structure after comments, formatting, spans, provenance, and ordinary local or term names are erased. This structural identity is not arbitrary program equivalence.
• Handlers are deep. multi operations bind reusable continuations; once operations bind affine Resume values with static and runtime reuse checks.

This file is self-contained for public use. A repository checkout is needed only to develop the OCaml implementation, not to install or write Jacquard.

Install

The release installer downloads a checksum-verified binary, the standard prelude, demos, and the C runtime used by native builds. It does not require OCaml, opam, or Dune.

curl -fsSL https://raw.githubusercontent.com/jbwinters/jacquard-lang/jacquard-core-0.2.0/scripts/install.sh | sh
export PATH="$HOME/.local/bin:$PATH"
jac --version
jac run "$HOME/.local/share/jacquard/demos/basics/m1-fact.jac"
sh "$HOME/.local/share/jacquard/demos/case-studies/release-risk/run.sh"

The jac run command prints 120; the final command runs the larger release risk narrative. The published targets are Linux x86-64, macOS Intel, and macOS Apple Silicon. Set JACQUARD_INSTALL_PREFIX to choose a different prefix and JACQUARD_INSTALL_VERSION to choose another release tag. The long command is jacquard; jac is its installed short alias.

Shipped *.sh demo launchers work without a source checkout. Use them for models that require an inference driver and for multi-file narratives; directly running an observe model under jac run correctly fails with E0904.