Gleam command line argument parsing with basic flag support.
To install from hex:
gleam add glint
glint
is conceptually quite small, your general flow will be:
- create a new glint instance with
glint.new
- configure it with
glint.with_pretty_help
and other configuration functions - add commands with
glint.add
- create a new command with
glint.cmd
- assign that command any flags required
- assign the command a custom description
- create a new command with
- run your cli with
glnt.run
, run with a function to handle command output withglint.run_and_handle
Glint works amazingly with these other packages:
- argv, use this for cross-platform argument fetching
- gleescript, use this to generate erlang escripts for your applications
You can import glint
as a dependency and use it to build simple command-line applications like the following simplified version of the the hello world example
// stdlib imports
import gleam/io
import gleam/list
import gleam/result
import gleam/string.{uppercase}
// external dep imports
import snag
import argv
// glint imports
import glint
import glint/flag
/// the key for the caps flag
const caps = "caps"
/// a boolean flag with default False to control message capitalization.
///
fn caps_flag() -> flag.FlagBuilder(Bool) {
flag.bool()
|> flag.default(False)
|> flag.description("Capitalize the hello message")
}
/// the command function that will be executed
///
fn hello(input: glint.CommandInput) -> Nil {
let assert Ok(caps) = flag.get_bool(from: input.flags, for: caps)
let name =
case input.args {
[] -> "Joe"
[name,..] -> name
}
let msg = "Hello, " <> name <> "!"
case caps {
True -> uppercase(msg)
False -> msg
}
|> io.println
}
pub fn main() {
// create a new glint instance
glint.new()
// with an app name of "hello", this is used when printing help text
|> glint.with_name("hello")
// with pretty help enabled, using the built-in colours
|> glint.with_pretty_help(glint.default_pretty_help())
// with a root command that executes the `hello` function
|> glint.add(
// add the command to the root
at: [],
// create the command, add any flags
do: glint.command(hello)
// with flag `caps`
|> glint.flag(caps, caps_flag())
// with a short description
|> glint.description("Prints Hello, <NAME>!"),
)
|> glint.run(argv.load().arguments)
}