Editing ParEdit

'''ParEdit''' (##paredit.el##) is a minor mode for performing structured editing of S-expression data. The typical example of this would be Lisp or Scheme source code. %%ParEdit%% helps __**keep parentheses balanced**__ and adds many keys for moving S-expressions and moving around in S-expressions. Its behavior can be jarring for those who may want transient periods of unbalanced parentheses, such as when typing parentheses directly or commenting out code line by line. Skeleton like matching paren insertion is a small part of ParEdit's functionality; its true genius won't be obvious until you code in some list oriented language. '''The latest stable version is available at <tt>[mumble.net/~campbell/emacs/paredit.el paredit.el]</tt>.''' See also the [mumble.net/~campbell/emacs/paredit.html Reference Table], the [mumble.net/~campbell/emacs/paredit.release Release Notes] and the PareditCheatsheet. There is also a [pub.gajendra.net/src/paredit-refcard.pdf Paredit reference card] modeled on the cheat sheet. The latest ''development'' version is available at <tt>[mumble.net/~campbell/emacs/paredit-beta.el paredit-beta.el]</tt> ([mumble.net/~campbell/emacs/paredit-beta.html Reference Table]). A spinoff of %%ParEdit%% (by the same author) is also now available in the current CVS version of EdWin, MIT Scheme's Emacs clone. Type ##M-x paredit-mode RET## to enable it, or add the following code to your ##.edwin## file to enable it automatically in the Scheme mode: (add-event-receiver! (ref-variable scheme-mode-hook) (lambda (buffer) (enable-buffer-minor-mode! buffer (ref-mode-object paredit)))) (You can substitute other modes for ##scheme-mode## also.) == Activate it automatically == To use %%ParEdit%% with Emacs' Lisp modes, add the following to <tt>[InitFile .emacs]</tt>: (autoload 'paredit-mode "paredit" "Minor mode for pseudo-structurally editing Lisp code." t) (add-hook 'emacs-lisp-mode-hook (lambda () (paredit-mode +1))) (add-hook 'lisp-mode-hook (lambda () (paredit-mode +1))) (add-hook 'lisp-interaction-mode-hook (lambda () (paredit-mode +1))) (add-hook 'scheme-mode-hook (lambda () (paredit-mode +1))) == ParEdit and ElDoc == To use %%ParEdit%% with ElDoc, you should make !ElDoc aware of %%ParEdit%%'s most used commands: (require 'eldoc) ; if not already loaded (eldoc-add-command 'paredit-backward-delete 'paredit-close-round) Whenever the listed commands are used, !ElDoc will automatically refresh the minibuffer. [new:PhilHudson:2013-01-18 12:07 UTC] No such function as ##paredit-close-round## exists in paredit.el (emacs 24.3) [new] After you load paredit, `paredit-close-round' is defined. -- AaronHawley [new:PhilHudson:2013-01-18 16:13 UTC] My bad (or debian's): I had the ancient debian package ##paredit-el## installed. Ignore. -- PhilHudson. == ParEdit and SLIME REPL == (add-hook 'slime-repl-mode-hook (lambda () (paredit-mode +1))) SLIME's REPL has the very annoying habit of grabbing DEL which interferes with paredit's normal operation. To alleviate this problem use the following code: ;; Stop SLIME's REPL from grabbing DEL, ;; which is annoying when backspacing over a '(' (defun override-slime-repl-bindings-with-paredit () (define-key slime-repl-mode-map (read-kbd-macro paredit-backward-delete-key) nil)) (add-hook 'slime-repl-mode-hook 'override-slime-repl-bindings-with-paredit) == ParEdit and "Electric RETURN" == ParEdit works particularly well with an "electric" ##RETURN## function. If ##RETURN## is pressed when the cursor is before a closing paren, the following code will add an extra newline. The extra newlines are re-gathered by ##paredit-close-round##, which ParEdit binds to "##)##" by default. The code is loosely based on code on the AutoPairs page: (defvar electrify-return-match "[\]}\)\"]" "If this regexp matches the text after the cursor, do an \"electric\" return.") (defun electrify-return-if-match (arg) "If the text after the cursor matches `electrify-return-match' then open and indent an empty line between the cursor and the text. Move the cursor to the new line." (interactive "P") (let ((case-fold-search nil)) (if (looking-at electrify-return-match) (save-excursion (newline-and-indent))) (newline arg) (indent-according-to-mode))) ;; Using local-set-key in a mode-hook is a better idea. (global-set-key (kbd "RET") 'electrify-return-if-match) == ParEdit, ElDoc, Show-Paren and "Electric RETURN" == Here's a '''[img8.imageshack.us/img8/9479/openparen.gif short video demonstration]''' of %%ParEdit%% working with %%ElDoc%% and %%Show-Paren%% minor modes along with the electric ##RETURN## function defined above. Off-topic question: what font are you using? It looks like Monaco, but it has a different "a". Thanks. Adding this code to your <tt>[InitFile .emacs]</tt> will set the modes as in the video: (add-hook 'emacs-lisp-mode-hook (lambda () (paredit-mode t) (turn-on-eldoc-mode) (eldoc-add-command 'paredit-backward-delete 'paredit-close-round) (local-set-key (kbd "RET") 'electrify-return-if-match) (eldoc-add-command 'electrify-return-if-match) (show-paren-mode t))) == ParEdit, and extreme barfarge and slurpage == There are times when I'm in a list like '''(a b| c d e f g)''', and I know that want to barf out everything following point from the current form. Since ##C-}## doesn't take a prefix argument, there's really no quick way to do this with the standard paredit.el mode. To solve this problem I've written some extreme barfage and slurpage commands, so that ##C-M-}## will do what I described and yield '''(a b) c d e f g'''. Evaluate the following after paredit is loaded: (defun paredit-barf-all-the-way-backward () (interactive) (paredit-split-sexp) (paredit-backward-down) (paredit-splice-sexp)) (defun paredit-barf-all-the-way-forward () (interactive) (paredit-split-sexp) (paredit-forward-down) (paredit-splice-sexp) (if (eolp) (delete-horizontal-space))) (defun paredit-slurp-all-the-way-backward () (interactive) (catch 'done (while (not (bobp)) (save-excursion (paredit-backward-up) (if (eq (char-before) ?\() (throw 'done t))) (paredit-backward-slurp-sexp)))) (defun paredit-slurp-all-the-way-forward () (interactive) (catch 'done (while (not (eobp)) (save-excursion (paredit-forward-up) (if (eq (char-after) ?\)) (throw 'done t))) (paredit-forward-slurp-sexp)))) (nconc paredit-commands '("Extreme Barfage & Slurpage" (("C-M-)") paredit-slurp-all-the-way-forward ("(foo (bar |baz) quux zot)" "(foo (bar |baz quux zot))") ("(a b ((c| d)) e f)" "(a b ((c| d)) e f)")) (("C-M-}" "M-F") paredit-barf-all-the-way-forward ("(foo (bar |baz quux) zot)" "(foo (bar|) baz quux zot)")) (("C-M-(") paredit-slurp-all-the-way-backward ("(foo bar (baz| quux) zot)" "((foo bar baz| quux) zot)") ("(a b ((c| d)) e f)" "(a b ((c| d)) e f)")) (("C-M-{" "M-B") paredit-barf-all-the-way-backward ("(foo (bar baz |quux) zot)" "(foo bar baz (|quux) zot)")))) (paredit-define-keys) (paredit-annotate-mode-with-examples) (paredit-annotate-functions-with-examples) -- JohnWiegley == Discussion == I downloaded %%ParEdit%% a long time ago, but I did not succeed in using it daily. I have two questions here: 1. What is really ''useful'' with %%ParEdit%% that we can't get with standard skeletons? [new] :[new:LeWang:2010-12-27 02:46 UTC] On the surface it looks like both ParEdit and skeleton are inserting matching parenthesis. However, a skeleton insertion is the end of the story. Think of a ParEdit insertion is just an indicator to show *you* the context. You can move past ")" to use it or just completely pretend it's not there. The insertion is just a side-effect of ParEdit's true purpose -- *clarify context while coding*. -- LeWang : Check out the %%ParEdit%% reference table mentioned above, especially the parts "Depth-Changing Commands" and "Barfage & Slurpage". Skeletons are like templates, they're static. %%ParEdit%% can modify the structure of Lisp code. So basically, they have different purposes. -- PeterBarabas [new] 2. How do you delete a parenthesis? I often end up with unbalanced parentheses when coding something (without paredit), and activating %%ParEdit%% prevents me from deleting the leading parenthesis. [new] : It takes a bit of getting used to, but after that you'll never end up with unbalanced parentheses. Just use %%ParEdit%%'s commands, e.g., ##paredit-open-parenthesis##, ##paredit-wrap-sexp## instead of manually typing/editing parentheses. %%ParEdit%% really makes transforming Lisp code easy. -- PeterBarabas [new] : Expression validity isn't enforced with ##C-w##; I find that's the easiest way to make a quick fix that %%ParEdit%% won't like. [new] : ##C-u DEL## falls back to `backward-delete-char'. Similarly, you can insert single parentheses with ##C-q (## and ##C-q )##. -- YannHodique [new] : Works like a charm! -- XavierMaillard [new] 3. I'm working on a mode for a syntax where m#foo is a legal symbol but otherwise, # comments out the line (like in shell scripts). For some reason, putting (paredit-mode 1) in a run-hook for this mode, or in sh-mode-hook, makes it complain on a line like (foo m#bar) with ''condition-case: Unmatched bracket or quote''. But, if I turn on paredit-mode _after_ doing ##M-x sh-mode##, it works fine, and I can edit around parens just as if they said (foo bar). Anyone know why this happens? [new] 4. I'll bite. Can anyone tell me what's going on in the "Short video demonstration" video above? I turn on %%ParEdit%% and I don't get newlines after my parens and I don't get it showing me what comes next after typing "defun". If these are other major/minor modes then the caption should be replaced with "Here's a demonstration of %%ParEdit%% playing nice with secret-mode.el and fun-minor-mode-that-were-keeping-secret-from-dale.el. : -- DaleWiles [new] It is implicit by the context, the two features you are seeing are "eldoc" and "electric RET" which has a snippet of code just under the video link for you to try it :) -- GlauberPrado [new] 5. Older version of Paredit managed newlines differently to the current beta version. I would like to suggest newline insertion context-based. It should add a newline after, for example, of close the right parenthesis of a last of arguments in defun. Many examples can be thought. I am aware it could be instrusive and some paredit users reject this feature. Although it could be an optional feature. What do you think? [new:stepnem:2010-07-17 12:57 UTC] : I really see no need for this kind of complexity -- I imagine it would be hard to implement and impossible to satisfy the varying users' needs. Currently you have both `paredit-close-round' and `paredit-close-round-and-newline'. You can bind these to any keys you like (##)## and ##M-)## by default). I find manually choosing the right behaviour much more useful than some kind of "AI" in this regard. -- stepnem ---- CategoryCode CategoryEditing CategoryParentheses.

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