https://github.com/troyp/fn.el

Concise anonymous functions for Emacs Lisp
https://github.com/troyp/fn.el

emacs emacs-lisp functional-programming lambda macros

Last synced: about 2 months ago
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Concise anonymous functions for Emacs Lisp

• Host: GitHub
• URL: https://github.com/troyp/fn.el
• Owner: troyp
• License: gpl-3.0
• Created: 2016-08-03T10:38:14.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2021-03-04T18:12:53.000Z (over 3 years ago)
• Last Synced: 2024-04-26T01:32:34.873Z (5 months ago)
• Topics: emacs, emacs-lisp, functional-programming, lambda, macros
• Language: Emacs Lisp
• Homepage:
• Size: 27.3 KB
• Stars: 27
• Watchers: 5
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
fn.el -- Concise anonymous functions for Emacs Lisp.

-----

__fn.el__ provides macros for writing concise and readable anonymous functions.

[![MELPA](https://melpa.org/packages/fn-badge.svg)](https://melpa.org/#/fn)

[![MELPA Stable](https://stable.melpa.org/packages/fn-badge.svg)](https://stable.melpa.org/#/fn)

------------------------------------------------------------

## Installation

* Install from [melpa](http://melpa.org/#/) using `M-x list-packages`.

* Or, place `fn.el` in any directory on your `load-path` and execute:

    (require 'fn)

------------------------------------------------------------

## API

* [fn](#fn-rest-body) `(&rest body)`

* [fn:](#fn-rest-body) `(&rest body)`

### fn `(&rest BODY)`

Return a function defined by BODY.

Intended for inline use where concision is desired.  If creating a function to

bind as a function value, use `lambda` or `-lambda`.

The definition BODY may use anaphoric parameters to refer to the arguments. For

a single-argument function, `<>` can be used. For a multiple-argument function,

use `<1>` to refer to the first argument, `<2>` to refer to the second, and so on

up to `<9>`. The parameter `` refers to a list containing the (n+1)st and

later arguments, where `` is the highest numerical parameter supplied.

If applied to a literal, creates a constant function, or equivalently, a thunk

(since it can be called with any number of arguments).

    (-map (fn (* <> <>)) (number-sequence 0 10))

    ;; (0 1 4 9 16 25 36 49 64 81 100)

    (-map (fn (/ (-sum <>)

                (length <>)))

          '((3.0 4.0 5.0 5.0 10.0)

            (1.5 2.5 2.0)

            (1 5)))

    ;; (5.4 2.0 3)

    ;; find average of each list

    (-filter (fn (zerop (mod <> 3)))

            (number-sequence 1 10))

    ;; (3 6 9)

    (funcall (fn 7))

    ;; 7

    (funcall (fn (-map #'list )) 1 2 3 4)

    ;; ((1) (2) (3) (4))

    

### fn: `(&rest BODY)`

Return a function defined by (BODY).

Intended for inline use where concision is desired.  If creating a function to

bind as a function value, use `lambda` or `-lambda`.

Identical to `fn` except that BODY is automatically parenthesized.

The definition BODY may use the anaphoric parameter `<>` for the sole argument,

or `<1>` ... `<9>` to refer to multiple positional arguments. The parameter

`` refers to a list containing the (n+1)st and later arguments, where `` is

the highest numerical parameter supplied.

    (-map (fn: * <> <>) (number-sequence 0 10))

    ;; (0 1 4 9 16 25 36 49 64 81 100)

    (-filter (fn: > <> 0)

            '(-5 2 0 0 3 -1 0 4))

    ;; (2 3 4)