nu_plugin_functional

Functional-like commands for nushell.

WIP: This plugin is still work in process

Tested with nushell==0.113.1

Build and install

This plugin requires:

• nushell >= 0.113.1
• rust preferred lastest stable version.

To build:

# Release build
cargo build -r

# Debug build
cargo build

To install, follow the official instruction for third-party plugins.

Commands

other

Use another value if input is null.

$ null | fp other 100
100

$ 1 | fp other 100
1

$ let foo = 100; null | fp other {|| $foo + 2}
102

first-where

Get the first element in list/table/range that meets a given condition.

Return null if no element meets the condition.

$ [1, 2, 4] | fp first-where $it > 5
<output nothing>

$ [1, 2, 4, 8] | fp first-where {|x| $x > 5}
8

is

Check if input type is a specified type.

$ 1 | fp is int
true

$ [1, 2] | fp is list
true

$ [1, 2] | fp is list<string>
false

then

Do something if input is not null.

$ 100 | fp then {$in + 2}
102

$ let foo = 2; 1 | fp then {|x| $x + $foo}
3

$ null | fp then 100
<output nothing>

$ [1, 2, 4, 8] | fp first-where $it > 5 | fp then {$in * 2}
16

pure

Convert a value to null if it is the default value of its type.

For the following types:

• int: 0
• float: 0.0, Nan, Inf, -Inf
• string: (empty string) '', ""
• boolean: false
• duration 0day, 0hr, 0min, 0sec
• fize-size: 0b, 0kb, 0mb, 0gb, 0tb, 0pb, 0eb
• list: []
• record: {}
• table: [{}]
• nothing: null

values will be converted to null.

These yypes are not supported:

• date
• range
• binary
• closure
• block
• any
• glob
• error

$ 0 | fp pure | describe
nothing

$ false | fp pure | describe
nothing

$ [] | fp pure | describe
nothing

handle

A combination of then and other: do something when input is good and do some other thing if input is bad.

"bad" means the input is null.

$ 100 | fp handle {$in + 200} {200}
300

$ null | fp handle {$in + 200} {200}
200

$ [1,2,3] | fp pure | fp handle {|x| $x | each {$in + 10} } {[200,300,400]}
[11,12,13]

$ [] | fp pure | fp handle {|x| $x | each {$in + 10} } {[200,300,400]}
[200,300,400]