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CLI Reference

The Duckstruct compiler is shipped as the ds executable (built from this repository).

Common commands​

ds init [path]​

Creates a new project in the given directory (or the current directory):

  • duckstruct.toml
  • src/main.ds
  • .gitignore

ds compile <path>​

Compiles a .ds file or a project directory.

  • If <path> is inside a project (a directory containing duckstruct.toml), Duckstruct uses the manifest to choose the entrypoint and output location.
  • Compilation includes type checking; failures print human-readable diagnostics.

Default project output locations:

  • JavaScript: output/js/index.js (unless output is set in duckstruct.toml)
  • LLVM: output/llvm/index.ll (when configured)

Aliases: ds c, ds build

ds check​

This command is intended for editor integrations: it prints LSP-style JSON diagnostics and requires --json.

For day-to-day use, prefer ds compile to see human-readable errors.

ds ide ...​

IDE support commands used by the VS Code extension / language server.

ds (no subcommand)​

Running ds with no subcommand starts the REPL.

ds --eval "<source>"​

Typecheck and evaluate a small snippet, printing an inferred type string.

duckstruct.toml​

Common keys:

entrypoint = "src/main.ds"

# Optional: where build artifacts go (default: "output")
output = "dist"

[target]
# "js" (default) or "llvm"
backend = "js"

# LLVM-only: link an executable (optional)
link = true

# Used as the executable name when linking (optional)
name = "my-tool"