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Questions tagged [elisp]

for questions about Emacs Lisp as a Lisp dialect, that is, questions *about the language* itself. DO NOT USE it for questions about customization or how to write an application. Emacs Lisp is the scripting and programming language that the Emacs editor is built on.

2
votes
1answer
33 views

what does grave accent ` and aposrophe ' do in elisp regular expression?

I use C-h v to check the doc about this variable org-agenda-file-regexp. It says it is a variable defined in ‘org.el’. Its value is "\\`[^.].*\\.org\\'" What is the meaning of grave accent ` and ...
0
votes
1answer
126 views

What is a cons cell? [closed]

How is implemented a cons cell? Note: the title is different than the question for readability. This question is better defined than my deleted question "What is a list?" because I made some progress ...
1
vote
1answer
39 views

How to match an expression under the cursor?

I'm trying to match an expression under the cursor. In this case it happens to be reStructuredText, however I don't think that's such an important detail. :role:`Some Content` While this works, it ...
1
vote
1answer
41 views

Updating code from lexical-let to lexical-binding: t

This code shows an elisp function (third example) using lexical-let, which is now passe as I understand. How would it be written today with lexical scope now being a quasi-built-in feature of elisp? ...
6
votes
1answer
125 views

Shortening trees list with (setcdr (nthcdr 2 trees) nil)

I am starting to learn elisp and working through this tutorial https://www.gnu.org/software/emacs/manual/html_node/eintr/kill_002dnew-function.html and I do not understand this basic example: (setq ...
3
votes
1answer
133 views

How remove lines which are not equal in two buffers?

Consider the following buffers buffer_1: 11111111 22222222 33333333 44444444 buffer_2: 55555555 66666666 22222222 44444444 I need to remove all lines which are not equal in buffer_1 and buffer_2. ...
1
vote
1answer
26 views

How to define a function that calls two commands where the first one requires an arguments

I use emms to play music in emacs and I have this function to add a music directory and shuffle it. (defun my-emms-command() "Run `emms-add-directory' and `emms-...
0
votes
1answer
87 views

How to execute elisp commands

Related Question Hi, I want to give an elisp command which extracts the words between two arbitrary symbols. I searched google for elisp and the first item was emacs lisp, which I guess it means a ...
2
votes
1answer
44 views

How to write a list literal with conditional items? [duplicate]

Given a list literal '(1 2 3) is it possible to conditionally include parts of the list? eg: '(1 2 3 (when thing-is-true '(10 11 12))) 4 5 6) Which would result in '(1 2 3 4 5 6) or '(1 2 3 ...
0
votes
1answer
34 views

how to generate dynamic json data with emacs (macros)?

I was in a meeting yesterday where I was presenting a program that referenced a certain json file with data like this: [ { id: 1, text: '...', ... }, { id: 2, text: '...', ... } ] In ...
0
votes
1answer
37 views

(interactive “r”) can't be used directly after Emacs startup

The proper way to deal with region is using (interactive "r"). But in my case, (interactive "r") always complaints 'The mark is not set now, so there is no region' after fresh Emacs startup. This ...
0
votes
1answer
64 views

How to prevent “the function ‘->’ is not known to be defined.” warning

How do I prevent flycheck from triggering a warning for the following code: (defun file-path-last-segment () "Get last segment of file path for use in snippets." (-> default-directory (...
35
votes
8answers
4k views

How can I start learning Emacs Lisp?

Background: I'm mostly a vi user and am converting to Emacs. Past the basics and now use it for writing code in C and some Python with plans to do an R conversion too. I wrote (Common) LISP for ...
0
votes
0answers
28 views

Is #'(lambda …) historical legacy? [duplicate]

(elisp) Anonymous Functions says The following forms are all equivalent: (lambda (x) (* x x)) (function (lambda (x) (* x x))) #'(lambda (x) (* x x)) Because (lambda ...) is the most concise, I ...
3
votes
1answer
85 views

About closure creation

After reading this article about readable closures, I check that: Since closures are byte-code function objects, they print readably. You can capture an environment in a closure, serialize it, ...
0
votes
0answers
42 views

Slime inspector for emacs lisp

I want to know, if there is some possibility of inspecting an object as slime inspector does. For example, using libyaml I get the following result, it worked well: ELISP> (yaml-read-from-string ...
3
votes
3answers
196 views

Automatically installing the available version of org

Based on this reply, my code has the following function that installs its dependencies: (defun literef-install-packages() "Install any missing packages. The code is taken from `https://...
2
votes
2answers
64 views

Evaluating symbol in function arguments affected by destructive operations?

While evaluating a function call, the arguments is from left to right. For example, (let ((x '(1 2 3))) (list (nreverse x) x)) ;; => ((3 2 1) (1)) The first argument (nreverse x) evaluates to (...
0
votes
1answer
64 views

Access document title, author, date with elisp

The beginning of my document looks like this #+TITLE: this is the document title #+AUTHOR: R. Wiggum #+DATE: 2018-09-12 How can I access these properties with LISP?
1
vote
1answer
88 views

are braces `{` and `}` used at all in elisp?

What is the convention for using { and } characters in Emacs Lisp if they are used at all? Do macros make use of them?
3
votes
1answer
43 views

formatting of elisp file is different in emacs and other text editor

I'm having an issue with formatting in that when I'm in emacs, the formatting looks fine: but when the file is viewed with a different text editor, the spaces are different. this only occurs in the ...
1
vote
1answer
37 views

oddp vs cl-oddp in elisp script

I am trying to write a short script file with elisp for the first time which will serve me to install all the required packages that I use. Thus when I change from one computer to another, I can get ...
4
votes
4answers
253 views

Write `var0, var1, var2, …, var10` in a buffer

Most of the times there is no need to write manually many variables with the same name and a different index, like var0, var1, var2, var3, ..., var9 because one can use arrays, vectors or whatever ...
4
votes
2answers
92 views

Displaying buffer modification before end of function

I notice that Emacs waits for the end of a function to actually display the buffer modifications the function has produced. For instance, if a function looks like this: (defun foo () (interactive) ...
1
vote
1answer
57 views

\\{ in a doc string: what does it mean/do?

What does this backslash syntax mean? (defun elfeed-search-mode () "Major mode for listing elfeed feed entries. \\{elfeed-search-mode-map}" (interactive)
1
vote
1answer
187 views

how to call a c++ function from elisp

initially, i'am new to emacs. So I have little expierience with emacs. In past I used Visual Basic or VBA to work with the Output from some .dll. Now I'am working a little with emacs/elisp. My ...
1
vote
1answer
99 views

Return Value of apply-partially

I'm playing around with apply-partially and I'm confused about what gets returned when calling this function. The documentation states that apply-partially returns a function, but then I'd expect to ...
10
votes
3answers
138 views

Why does defvar scoping work differently without an initvalue?

Suppose I have a file named elisp-defvar-test.el containing: ;;; elisp-defvar-test.el --- -*- lexical-binding: t -*- (defvar my-dynamic-var) (defun f1 (x) "Should return X." (let ((my-dynamic-...
1
vote
1answer
253 views

What paradigm shift of my thinking must happen to understand the essence of Emacs/Emacs Lisp? [closed]

I've always had "AHA!"-moments when encountering new concepts or ideas in programming. That's when things start clicking for me. And I think I haven't yet had that moment with Emacs/Emacs Lisp yet. ...
1
vote
1answer
182 views

Kill initial buffers

I want to kill some buffers created by default, such as the GNU Emacs, but putting: (kill-buffer "*GNU Emacs*") On the .emacs doesn't work. I guess this code is called before the initial buffers are ...
1
vote
1answer
74 views

is there a function that can partially apply arguments on a function with order?

apply-partially cannot specify the order. Is there one from the default emacs installation that can specify order?
4
votes
2answers
85 views

How can I define new places for setf?

Q: how do I teach setf about new places it can set? In common lisp, one uses the macro defsetf to tell setf about new places it can set. In elisp, that macro exists in in the cl library, but, as far ...
2
votes
1answer
359 views

Call a function and insert text in minibuffer prompt

I'd like to define a key binding that calls a function and inserts some default input in the function's minibuffer prompt. For example, I'd like to call the command ivy-switch-buffer and automatically ...
4
votes
0answers
162 views

Is there an ELISP decompiler?

I'm thinking of writing one so that when I get those horrible tracebacks from bytecode files, I can better see where I was at. Is there one already? Are there any other tools for showing an error ...
4
votes
3answers
421 views

Is there an equivalent for defparameter on emacs-lisp?

I know we have defvar and setq. defvar has a special meaning on defining global variables because the assignment only happens once. So I was thinking about use setq to get the desired behavior of ...
6
votes
3answers
2k views

How to wrap a single string literal across multiple lines?

Is it possible to write a single line for an Elisp string: "hello world" As: "hello world" Without inserting a newline character? (wrapping a string literal). I read that adding a tilde at the ...
2
votes
1answer
216 views

How to use custom macro indentation in elisp?

This blog post shows that its possible to indent like this: (lispy-dotimes arg (when (= (point) (point-max)) (error "Reached end of buffer")) (forward-list)) Instead of this: (lispy-dotimes ...
2
votes
1answer
256 views

orgmode - babel language elisp vs. emacs-lisp

I am not sure what's the difference between elisp and emacs-lisp. In my environment, both work for elisp code but I did not found elisp from the load language list: #+BEGIN_SRC elisp :results output (...
1
vote
1answer
48 views

practical relevance of storing value and function into one symbol

With Emacs Lisp it is possible to store a value and a function within the same symbol. (setq foo 6) (defun foo () (message "blah %d" foo))) Then you can do: (symbol-function 'foo) which returns the ...
1
vote
1answer
61 views

How to print a quoted sexp using '… (reader syntax) instead of using (quote …)?

The result of (print 'foo) is (quote foo). Is there a similar function whose result is 'foo, which is what people generally write?
4
votes
1answer
118 views

Elisp backtrace print garbage messages

I'm using emacs 25.2 on osx 10.12 and following elisp intro to produce some error message intentionally. (This is a list) After I run C-x C-e on this line. A backtrace buffer appeared as supposed ...
1
vote
0answers
31 views

How to de-instrument elisp function? [duplicate]

To instrument an elisp function means to set up Emacs in such a way that whenever the function gets executed, debug mode is entered so the function can be executed stepwise. To instrument a function, ...
0
votes
0answers
50 views

Byte Compiling Functions Using `defalias` for `progn`

The following code: (defalias 'new-progn 'progn) (defun foo () (new-progn "foo")) (byte-compile 'foo) (foo) gives this error: Debugger entered--Lisp error: (invalid-function #<subr progn>) ...
5
votes
0answers
117 views

Structure-preserving copying of sequences

The form (cl-copy-tree TREE t) returns a deep-copy of a sequence TREE. The the Common Lisp Hyper Spec explains that copy-tree does not preserve circularities and sharing of substructures. I.e., even ...
1
vote
2answers
146 views

Wrapper objects / types for Emacs Lisp primitives?

I'm curious if there's any precedent for wrapper objects or types in Emacs Lisp. Javascript notably has built-in types that wrap built-in literal types and those objects can largely be used in the ...
1
vote
1answer
51 views

File mode name with -mode suffix or not?

I am not sure when I should name file x-mode.el and when x.el. Note that because of established practice mode writer should put (provide 'x) or (provide x-mode) to the end of file and end-users load ...
7
votes
2answers
359 views

The default value of buffer-local variable not set until first `setq`

Say I define a buffer-local variable foo, and its default value is "a": (defvar foo "a") (make-variable-buffer-local 'foo) (default-value 'foo) ;; => "a" Immediately after this I run the ...
1
vote
1answer
356 views

Passing a symbol as an argument to a function

I'm trying to understand why this doesn't work, and how to make it work: (defvar test/var-1 nil) (defvar test/var-2 nil) (defun make-setter (var-to-set) (lambda (val-to-set) (setq var-to-set ...
0
votes
0answers
41 views

alist error when value created using (concat string1 string2) [duplicate]

I'm really confused with what's happening here. In my config for backups I've the line (setq backup-directory-alist '(("" . "~/.emacs.d/backup/per-save"))) and I've a defined a variable in my init....
0
votes
2answers
97 views

Warning assigning variables

I'm rebuilding my emacs configuration, and trying to compile without warnings. I'm using also cask. I have this case: (require 'magit) ;; Enable a right limit of 70 chars for git logs (add-hook '...