ng-clp

Ng-clp (no-grammar definition command-line parser) is one of Rust's command-line parsers. A normal command-line parser generates a parser from the definition of command-line options that accepts a command line according to its grammar. In contrast, ng-clp uses a universal parser to discover what it assumes to be options or arguments from the given command-line arguments.

How it works?

You can run a sample program with cargo run as follows:

$ cargo run -- foo -bar bal --bra boo
Argument: foo
Option: -b ar
Argument: bal
Option: --bra boo

Format of flags and options accepted by ng-clp

The arguments, flags, and options accepted by ng-clp can be described as follows (option names, arguments, etc. are capitalized here to be easier to distinguish).

"But isn't that ambiguous?" If you are wondering, you are correct.

When the command line is:

-a bc

ng-clp allows treating with the command line in the following two interpretations.

• A flag -a appears (with no argument; the following bc is a normal command-line argument that has nothing to do with the flag -a).
• An option -a appears with argument bc.

How do I use ng-clp?

(1) Add a dependency to ng-clp and anyhow in Cargo.toml:

[dependencies]
ng-clp = "0.3"
anyhow = "1.0"

(2) Copy the boilerplate code boilerplate/main.rs in your main.rs and modify it.

License

MIT/Apache-2.0

Links

• ng-clp's page in Crates.io
• ng-clp's repository in GitHub

ng-clp is based on the same idea as the original product gzclp, but their APIs are completely different from each other.