Running .mbtx Scripts

Running .mbtx Scripts#

The Moon build system lets you write script files in MoonBit without any module or package configuration files. Script files use the special .mbtx extension.

Run a .mbtx file#

Write a script script.mbtx:

///|
import {
  "moonbitlang/core/list" @ls
}

///|
async fn main {
  let xs = @ls.from_array(["1", "2", "3"])
  debug(xs)
}

Then run this script directly:

$ moon run script.mbtx

In .mbtx, you can declare imports at the top of the file using the same syntax as package configuration. There is one difference: import paths can optionally include a version @version after the module name:

///|
import {
  "moonbitlang/async@0.17.0/fs",
  "moonbitlang/async@0.17.0",
}

///|
async fn main {
  ...
}

All imported packages from the same module must use the same version.

If the import path is not explicitly versioned, it uses the latest version in the local registry index.

Run a .mbtx script from stdin#

Moon supports running a .mbtx script from stdin:

$ cat script.mbtx | moon run -

For short scripts, pass the .mbtx source directly with -c:

$ moon run -c "<script>"
$ moon run -c 'fn main { println("hello") }'

You can also use a heredoc, a feature provided by the shell:

$ moon run - <<EOF
fn main {
  println("hello")
}
EOF
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