nushell/crates/nu-utils/standard_library/std.nu
Antoine Stevan 6af59cb0ea
FEATURE: add a path add to the standard library (#8303)
# Description
this PR adds the `path add` command to
`crates/nu-utils/standard_library/std.nu`
- this comes from frequent questions over on the discord server, about
how to add directories to the `PATH`
- this is greatly inspired from the [original
`path-add`](https://discord.com/channels/601130461678272522/615253963645911060/1081206660816699402)
from @melMass
- allows to prepend and append a variable number of directories to the
`PATH`
- i've added a description with an example
- i've added tests in `crates/nu-utils/standard_library/tests.nu` that
hopefully covers all the features

# User-Facing Changes
`path add` can now be used from `std.nu`

# Tests + Formatting
the tests pass with
```bash
nu crates/nu-utils/standard_library/tests.nu
```

# After Submitting
```bash
$nothing
```
2023-03-07 17:06:14 -06:00

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def _assert [
cond: bool
msg: string
] {
if not $cond {
error make {msg: $msg}
}
}
# ```nushell
# >_ assert ($a == 3)
# >_ assert ($a != 3)
# Error:
# × condition given to `assert` does not hold
# ╭─[entry #12:5:1]
# 5 │ if not $cond {
# 6 │ error make {msg: $msg}
# · ─────┬────
# · ╰── originates from here
# 7 │ }
# ╰────
# ```
export def assert [cond: bool] {
_assert $cond "condition given to `assert` does not hold"
}
# ```nushell
# >_ assert_eq $a "a string"
# Error:
# × left and right operand of `assert eq` should have the same type
# ╭─[entry #12:5:1]
# 5 │ if not $cond {
# 6 │ error make {msg: $msg}
# · ─────┬────
# · ╰── originates from here
# 7 │ }
# ╰────
#
# >_ assert_eq $a 3
# >_ assert_eq $a 1
# Error:
# × left is not equal to right
# ╭─[entry #12:5:1]
# 5 │ if not $cond {
# 6 │ error make {msg: $msg}
# · ─────┬────
# · ╰── originates from here
# 7 │ }
# ╰────
# ```
export def "assert eq" [left: any, right: any] {
_assert (($left | describe) == ($right | describe)) $"left and right operand of `assert eq` should have the same type"
_assert ($left == $right) "left is not equal to right"
}
# ```nushell
# >_ assert_ne $a "a string"
# Error:
# × left and right operand of `assert eq` should have the same type
# ╭─[entry #12:5:1]
# 5 │ if not $cond {
# 6 │ error make {msg: $msg}
# · ─────┬────
# · ╰── originates from here
# 7 │ }
# ╰────
#
# >_ assert_ne $a 1
# >_ assert_ne $a 3
# Error:
# × left is equal to right
# ╭─[entry #12:5:1]
# 5 │ if not $cond {
# 6 │ error make {msg: $msg}
# · ─────┬────
# · ╰── originates from here
# 7 │ }
# ╰────
# ```
export def "assert ne" [left: any, right: any] {
_assert (($left | describe) == ($right | describe)) $"left and right operand of `assert eq` should have the same type"
_assert ($left != $right) "left is equal to right"
}
# ```nushell
# >_ let branches = {
# ))) 1: { print "this is the 1st branch"}
# ))) 2: { print "this is the 2nd branch" }
# ))) 3: { print "this is the 3rd branch" }
# ))) 4: { print "this is the 4th branch" }
# ))) }
#
# >_ match 1 $branches
# ))) match 2 $branches
# ))) match 3 $branches
# ))) match 4 $branches
# ))) match 5 $branches
# this is the 1st branch
# this is the 2nd branch
# this is the 3rd branch
# this is the 4th branch
#
# >_ match 1 $branches { "this is the default branch" }
# ))) match 2 $branches { "this is the default branch" }
# ))) match 3 $branches { "this is the default branch" }
# ))) match 4 $branches { "this is the default branch" }
# ))) match 5 $branches { "this is the default branch" }
# this is the 1st branch
# this is the 2nd branch
# this is the 3rd branch
# this is the 4th branch
# this is the default branch
# ```
export def match [
input:string
matchers:record
default?: block
] {
if (($matchers | get -i $input) != null) {
$matchers | get $input | do $in
} else if ($default != null) {
do $default
}
}
# Add the given paths to the PATH.
#
# # Example
# - adding some dummy paths to an empty PATH
# ```nushell
# >_ with-env [PATH []] {
# std path add "foo"
# std path add "bar" "baz"
# std path add "fooo" --append
#
# assert eq $env.PATH ["bar" "baz" "foo" "fooo"]
#
# print (std path add "returned" --ret)
# }
# ╭───┬──────────╮
# │ 0 │ returned │
# │ 1 │ bar │
# │ 2 │ baz │
# │ 3 │ foo │
# │ 4 │ fooo │
# ╰───┴──────────╯
# ```
export def-env "path add" [
--ret (-r) # return $env.PATH, useful in pipelines to avoid scoping.
--append (-a) # append to $env.PATH instead of prepending to.
...paths # the paths to add to $env.PATH.
] {
let-env PATH = (
$env.PATH
| if $append { append $paths }
else { prepend $paths }
)
if $ret {
$env.PATH
}
}