zipspacemacsfile

[](https://github.com/magnars/dash.el/actions/workflows/test.yml) [](https://elpa.gnu.org/packages/dash.html) [](https://elpa.gnu.org/devel/dash.html) [](https://stable.melpa.org/#/dash) [](https://melpa.org/#/dash) # <img align="right" src="rainbow-dash.png"> dash.el A modern list API for Emacs. No [`'cl`](https://gnu.org/software/emacs/manual/html_node/cl/) required. See the end of the file for license conditions. ## Contents * [Change log](#change-log) * [Upcoming breaking change!](#upcoming-breaking-change) * [Installation](#installation) * [Functions](#functions) * [Contribute](#contribute) * [Contributors](#contributors) * [License](#license) ## Change log See the [`NEWS.md`](NEWS.md) file. ### Upcoming breaking change! - For backward compatibility reasons, `-zip` when called with two lists returns a list of cons cells, rather than a list of proper lists. This is a clunky API, and may be changed in a future release to always return a list of proper lists, as `-zip-lists` currently does. **N.B.:** Do not rely on the current behavior of `-zip` for two lists. Instead, use `-zip-pair` for a list of cons cells, and `-zip-lists` for a list of proper lists. ## Installation Dash is available on [GNU ELPA](https://elpa.gnu.org/), [GNU-devel ELPA](https://elpa.gnu.org/devel/), and [MELPA](https://melpa.org/), and can be installed with the standard command `package-install`: M-x package-install RET dash RET See [`(info "(emacs) Package Installation")`](https://gnu.org/software/emacs/manual/html_node/emacs/Package-Installation.html). Alternatively, you can just dump `dash.el` in your `load-path` somewhere. See [`(info "(emacs) Lisp Libraries")`](https://gnu.org/software/emacs/manual/html_node/emacs/Lisp-Libraries.html). ### Using in a package Add something like this to the library's headers: ;; Package-Requires: ((dash "2.19.1")) See [`(info "(elisp) Library Headers")`](https://gnu.org/software/emacs/manual/html_node/elisp/Library-Headers.html). ### Fontification of special variables Font lock of special Dash variables (`it`, `acc`, etc.) in Emacs Lisp buffers can optionally be enabled with the autoloaded minor mode `dash-fontify-mode`. In older Emacs versions which do not dynamically detect macros, the minor mode also fontifies Dash macro calls. To automatically enable the minor mode in all Emacs Lisp buffers, just call its autoloaded global counterpart `global-dash-fontify-mode`, either interactively or from your `user-init-file`: ```el (global-dash-fontify-mode) ``` ### Info symbol lookup While editing Elisp files, you can use `C-h S` (`info-lookup-symbol`) to look up Elisp symbols in the relevant Info manuals (see [`(emacs) Info Lookup`](https://gnu.org/software/emacs/manual/html_node/emacs/Info-Lookup.html)). To enable the same for Dash symbols, use the command `dash-register-info-lookup`. It can be called directly when needed, or automatically from your `user-init-file`. For example: ```el (with-eval-after-load 'info-look (dash-register-info-lookup)) ``` ## Functions All functions and constructs in the library use a dash (`-`) prefix. The library also provides anaphoric macro versions of functions where that makes sense. The names of these macros are prefixed with two dashes (`--`) instead of one. While `-map` applies a function to each element of a list, its anaphoric counterpart `--map` evaluates a form with the local variable `it` temporarily bound to the current list element instead. For example: ```el (-map (lambda (n) (* n n)) '(1 2 3 4)) ; Normal version. (--map (* it it) '(1 2 3 4)) ; Anaphoric version. ``` The normal version can of course also be written as follows: ```el (defun my-square (n) "Return N multiplied by itself." (* n n)) (-map #'my-square '(1 2 3 4)) ``` This demonstrates the utility of both versions. ### Maps Functions in this category take a transforming function, which is then applied sequentially to each or selected elements of the input list. The results are collected in order and returned as a new list. * [`-map`](#-map-fn-list) `(fn list)` * [`-map-when`](#-map-when-pred-rep-list) `(pred rep list)` * [`-map-first`](#-map-first-pred-rep-list) `(pred rep list)` * [`-map-last`](#-map-last-pred-rep-list) `(pred rep list)` * [`-map-indexed`](#-map-indexed-fn-list) `(fn list)` * [`-annotate`](#-annotate-fn-list) `(fn list)` * [`-splice`](#-splice-pred-fun-list) `(pred fun list)` * [`-splice-list`](#-splice-list-pred-new-list-list) `(pred new-list list)` * [`-mapcat`](#-mapcat-fn-list) `(fn list)` * [`-copy`](#-copy-list) `(list)` ### Sublist selection Functions returning a sublist of the original list. * [`-filter`](#-filter-pred-list) `(pred list)` * [`-remove`](#-remove-pred-list) `(pred list)` * [`-remove-first`](#-remove-first-pred-list) `(pred list)` * [`-remove-last`](#-remove-last-pred-list) `(pred list)` * [`-remove-item`](#-remove-item-item-list) `(item list)` * [`-non-nil`](#-non-nil-list) `(list)` * [`-slice`](#-slice-list-from-optional-to-step) `(list from &optional to step)` * [`-take`](#-take-n-list) `(n list)` * [`-take-last`](#-take-last-n-list) `(n list)` * [`-drop`](#-drop-n-list) `(n list)` * [`-drop-last`](#-drop-last-n-list) `(n list)` * [`-take-while`](#-take-while-pred-list) `(pred list)` * [`-drop-while`](#-drop-while-pred-list) `(pred list)` * [`-select-by-indices`](#-select-by-indices-indices-list) `(indices list)` * [`-select-columns`](#-select-columns-columns-table) `(columns table)` * [`-select-column`](#-select-column-column-table) `(column table)` ### List to list Functions returning a modified copy of the input list. * [`-keep`](#-keep-fn-list) `(fn list)` * [`-concat`](#-concat-rest-lists) `(&rest lists)` * [`-flatten`](#-flatten-l) `(l)` * [`-flatten-n`](#-flatten-n-num-list) `(num list)` * [`-replace`](#-replace-old-new-list) `(old new list)` * [`-replace-first`](#-replace-first-old-new-list) `(old new list)` * [`-replace-last`](#-replace-last-old-new-list) `(old new list)` * [`-insert-at`](#-insert-at-n-x-list) `(n x list)` * [`-replace-at`](#-replace-at-n-x-list) `(n x list)` * [`-update-at`](#-update-at-n-func-list) `(n func list)` * [`-remove-at`](#-remove-at-n-list) `(n list)` * [`-remove-at-indices`](#-remove-at-indices-indices-list) `(indices list)` ### Reductions Functions reducing lists to a single value (which may also be a list). * [`-reduce-from`](#-reduce-from-fn-init-list) `(fn init list)` * [`-reduce-r-from`](#-reduce-r-from-fn-init-list) `(fn init list)` * [`-reduce`](#-reduce-fn-list) `(fn list)` * [`-reduce-r`](#-reduce-r-fn-list) `(fn list)` * [`-reductions-from`](#-reductions-from-fn-init-list) `(fn init list)` * [`-reductions-r-from`](#-reductions-r-from-fn-init-list) `(fn init list)` * [`-reductions`](#-reductions-fn-list) `(fn list)` * [`-reductions-r`](#-reductions-r-fn-list) `(fn list)` * [`-count`](#-count-pred-list) `(pred list)` * [`-sum`](#-sum-list) `(list)` * [`-running-sum`](#-running-sum-list) `(list)` * [`-product`](#-product-list) `(list)` * [`-running-product`](#-running-product-list) `(list)` * [`-inits`](#-inits-list) `(list)` * [`-tails`](#-tails-list) `(list)` * [`-common-prefix`](#-common-prefix-rest-lists) `(&rest lists)` * [`-common-suffix`](#-common-suffix-rest-lists) `(&rest lists)` * [`-min`](#-min-list) `(list)` * [`-min-by`](#-min-by-comparator-list) `(comparator list)` * [`-max`](#-max-list) `(list)` * [`-max-by`](#-max-by-comparator-list) `(comparator list)` ### Unfolding Operations dual to reductions, building lists from a seed value rather than consuming a list to produce a single value. * [`-iterate`](#-iterate-fun-init-n) `(fun init n)` * [`-unfold