Typed results
Your CLI definition produces the Roc type your application consumes, including validated values and structured subcommands.
A Roc package for command-line applications
Weave a CLI from a type.
Define options, parameters, and nested subcommands with composable builders. Weaver handles parsing, validation, diagnostics, help, and version output.
Built for expressive CLIs
Useful diagnostics
Missing options, malformed values, duplicates, and unknown arguments produce focused errors with usage guidance.
Generated help
Descriptions, defaults, aliases, parameters, and versions stay synchronized with the parser that users actually run.
Examples
See each program run in a terminal, then explore the complete highlighted Roc source.
Basic
Options, flags, and positional values.
Run and read →Deploy
A realistic command with validation and repeatable labels.
Run and read →Subcommands
Nested commands with their own arguments.
Run and read →Default values
Typed defaults with explicit overrides.
Run and read →Single argument
A minimal required numeric option.
Run and read →Reference
- Latest API documentation — generated from the current main branch on every deployment.
- README guide — concepts, behavior, testing, and package usage.
- Latest release — download the current package bundle.