nushell/crates/nu-std/README.md
Stefan Holderbach c5aa15c7f6
Add top-level crate documentation/READMEs (#12907)
# Description
Add `README.md` files to each crate in our workspace (-plugins) and also
include it in the `lib.rs` documentation for <docs.rs> (if there is no
existing `lib.rs` crate documentation)

In all new README I added the defensive comment that the crates are not
considered stable for public consumption. If necessary we can adjust
this if we deem a crate useful for plugin authors.
2024-07-14 10:10:41 +02:00

2.2 KiB

Welcome to the standard library of `nushell`!

The standard library is a pure-nushell collection of custom commands which provide interactive utilities and building blocks for users writing casual scripts or complex applications.

To see what's here:

> use std
> scope commands | select name usage | where name =~ "std "
#┬───────────name────────────┬──────────────────────usage──────────────────────
0│std assert                 │Universal assert command
1│std assert equal           │Assert $left == $right
2│std assert error           │Assert that executing the code generates an error
3│std assert greater         │Assert $left > $right
4│std assert greater or equal│Assert $left >= $right
             ...                                     ...
─┴───────────────────────────┴─────────────────────────────────────────────────

🧰 Using the standard library in the REPL or in scripts

All commands in the standard library must be "imported" into the running environment (the interactive read-execute-print-loop (REPL) or a .nu script) using the use command.

You can choose to import the whole module, but then must refer to individual commands with a std prefix, e.g:

use std

std log debug "Running now"
std assert (1 == 2)

Or you can enumerate the specific commands you want to import and invoke them without the std prefix.

use std ["log debug" assert]

log debug "Running again"
assert (2 == 1)

This is probably the form of import you'll want to add to your env.nu for interactive use.

✏️ contribute to the standard library

You're invited to contribute to the standard library! See CONTRIBUTING.md for details