From: Artur Malabarba Date: Tue, 1 Dec 2015 12:13:25 +0000 (+0000) Subject: packages/let-alist: Define it as a :core package X-Git-Url: https://code.delx.au/gnu-emacs-elpa/commitdiff_plain/2d45570ea587b8f880d3633849ff5db5a6673cae packages/let-alist: Define it as a :core package --- diff --git a/externals-list b/externals-list index 23fe8ecf1..d024f974e 100644 --- a/externals-list +++ b/externals-list @@ -56,6 +56,7 @@ ("gnorb" :subtree "https://github.com/girzel/gnorb") ("ioccur" :subtree "https://github.com/thierryvolpiatto/ioccur.git") ("js2-mode" :subtree "https://github.com/mooz/js2-mode.git") + ("let-alist" :core "lisp/emacs-lisp/let-alist.el") ("math-symbol-lists" :subtree "https://github.com/vspinu/math-symbol-lists.git") ("nameless" :subtree "https://github.com/Malabarba/Nameless") ("names" :subtree "http://github.com/Malabarba/names") diff --git a/packages/let-alist/let-alist.el b/packages/let-alist/let-alist.el deleted file mode 100644 index ca7a904a0..000000000 --- a/packages/let-alist/let-alist.el +++ /dev/null @@ -1,142 +0,0 @@ -;;; let-alist.el --- Easily let-bind values of an assoc-list by their names -*- lexical-binding: t; -*- - -;; Copyright (C) 2014-2015 Free Software Foundation, Inc. - -;; Author: Artur Malabarba -;; Maintainer: Artur Malabarba -;; Version: 1.0.4 -;; Keywords: extensions lisp -;; Prefix: let-alist -;; Separator: - - -;; This file is part of GNU Emacs. - -;; GNU Emacs is free software: you can redistribute it and/or modify -;; it under the terms of the GNU General Public License as published by -;; the Free Software Foundation, either version 3 of the License, or -;; (at your option) any later version. - -;; GNU Emacs is distributed in the hope that it will be useful, -;; but WITHOUT ANY WARRANTY; without even the implied warranty of -;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -;; GNU General Public License for more details. - -;; You should have received a copy of the GNU General Public License -;; along with GNU Emacs. If not, see . - -;;; Commentary: - -;; This package offers a single macro, `let-alist'. This macro takes a -;; first argument (whose value must be an alist) and a body. -;; -;; The macro expands to a let form containing body, where each dotted -;; symbol inside body is let-bound to their cdrs in the alist. Dotted -;; symbol is any symbol starting with a `.'. Only those present in -;; the body are let-bound and this search is done at compile time. -;; -;; For instance, the following code -;; -;; (let-alist alist -;; (if (and .title .body) -;; .body -;; .site -;; .site.contents)) -;; -;; essentially expands to -;; -;; (let ((.title (cdr (assq 'title alist))) -;; (.body (cdr (assq 'body alist))) -;; (.site (cdr (assq 'site alist))) -;; (.site.contents (cdr (assq 'contents (cdr (assq 'site alist)))))) -;; (if (and .title .body) -;; .body -;; .site -;; .site.contents)) -;; -;; If you nest `let-alist' invocations, the inner one can't access -;; the variables of the outer one. You can, however, access alists -;; inside the original alist by using dots inside the symbol, as -;; displayed in the example above by the `.site.contents'. -;; -;;; Code: - - -(defun let-alist--deep-dot-search (data) - "Return alist of symbols inside DATA that start with a `.'. -Perform a deep search and return an alist where each car is the -symbol, and each cdr is the same symbol without the `.'." - (cond - ((symbolp data) - (let ((name (symbol-name data))) - (when (string-match "\\`\\." name) - ;; Return the cons cell inside a list, so it can be appended - ;; with other results in the clause below. - (list (cons data (intern (replace-match "" nil nil name))))))) - ((not (consp data)) nil) - (t (append (let-alist--deep-dot-search (car data)) - (let-alist--deep-dot-search (cdr data)))))) - -(defun let-alist--access-sexp (symbol variable) - "Return a sexp used to access SYMBOL inside VARIABLE." - (let* ((clean (let-alist--remove-dot symbol)) - (name (symbol-name clean))) - (if (string-match "\\`\\." name) - clean - (let-alist--list-to-sexp - (mapcar #'intern (nreverse (split-string name "\\."))) - variable)))) - -(defun let-alist--list-to-sexp (list var) - "Turn symbols LIST into recursive calls to `cdr' `assq' on VAR." - `(cdr (assq ',(car list) - ,(if (cdr list) (let-alist--list-to-sexp (cdr list) var) - var)))) - -(defun let-alist--remove-dot (symbol) - "Return SYMBOL, sans an initial dot." - (let ((name (symbol-name symbol))) - (if (string-match "\\`\\." name) - (intern (replace-match "" nil nil name)) - symbol))) - - -;;; The actual macro. -;;;###autoload -(defmacro let-alist (alist &rest body) - "Let-bind dotted symbols to their cdrs in ALIST and execute BODY. -Dotted symbol is any symbol starting with a `.'. Only those present -in BODY are let-bound and this search is done at compile time. - -For instance, the following code - - (let-alist alist - (if (and .title .body) - .body - .site - .site.contents)) - -essentially expands to - - (let ((.title (cdr (assq 'title alist))) - (.body (cdr (assq 'body alist))) - (.site (cdr (assq 'site alist))) - (.site.contents (cdr (assq 'contents (cdr (assq 'site alist)))))) - (if (and .title .body) - .body - .site - .site.contents)) - -If you nest `let-alist' invocations, the inner one can't access -the variables of the outer one. You can, however, access alists -inside the original alist by using dots inside the symbol, as -displayed in the example above." - (declare (indent 1) (debug t)) - (let ((var (make-symbol "alist"))) - `(let ((,var ,alist)) - (let ,(mapcar (lambda (x) `(,(car x) ,(let-alist--access-sexp (car x) var))) - (delete-dups (let-alist--deep-dot-search body))) - ,@body)))) - -(provide 'let-alist) - -;;; let-alist.el ends here