Gleam command line argument parsing with basic flag support.
To install from hex:
gleam add glint
You can import glint
as a dependency and use it as follows:
(found in test/mini_demo.gleam
, for a more complete example see test/demo.gleam
)
import gleam/io
import gleam/result
import gleam/string.{join, uppercase}
import gleam/function.{compose}
import gleam/erlang.{start_arguments}
import glint
import glint/flag
const caps = "caps"
fn hello(input: glint.CommandInput) -> Nil {
let assert Ok(caps) = flag.get_bool(from: input.flags, for: caps)
["Hello,", ..input.args]
|> case caps {
True -> compose(join(_, " "), uppercase)
False -> join(_, " ")
}
|> string.append("!")
|> io.println
}
pub fn main() {
let caps_flag =
flag.B
|> flag.default(False)
|> flag.new
|> flag.description("Capitalize the provided name")
glint.new()
|> glint.add(
at: [],
do: glint.command(hello)
|> glint.flag(caps, caps_flag)
|> glint.description("Prints Hello, <NAME>!"),
)
|> glint.with_pretty_help(glint.default_pretty_help())
|> glint.run(start_arguments())
}
Run it with either of:
gleam run Bob
,gleam run -- --caps=false Bob
, orgleam run Bob --caps=false
which will printHello, Bob!
gleam run -- --caps Bob
orgleam run -- --caps=true Bob
, orgleam run Bob --caps
which will printHELLO, BOB!
Run gleam run -- --help
to print the generated help message, which in this case will look like:
Prints Hello, <NAME>!
USAGE:
'gleam run <NAME>' or 'gleam run <NAME> --caps'
FLAGS:
--help Print help information
--caps=<CAPS> Capitalize the provided name
Note: Due to this issue commands with flags immediately after gleam run
must include the --
as shown above