Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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
34 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
28 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
31 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
42 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
7answers
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
25 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 ...
2
votes
1answer
73 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
37 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
153 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
36 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
48 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
83 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
39 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
34 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
248 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
55 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
145 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 ...
0
votes
1answer
84 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
120 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
0answers
98 views

Learning (Emacs) Lisp coming from languages like C, PHP [closed]

Not knowing (Emacs) Lisp has become a hindrance for configuring Emacs to my liking. And I'm also fascinating by this so-different-from-others language, so I really want to dive down into it and need ...
1
vote
1answer
245 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
149 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
66 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
79 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
324 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
156 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
387 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 ...
3
votes
2answers
1k 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
192 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
222 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
46 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
57 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
115 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
30 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
49 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
101 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
135 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
50 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
338 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
344 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
39 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
88 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 '...
5
votes
2answers
214 views

Reflection on function argument signatures

Is there anything built into elisp for reflection on function argument signatures? I have used (length (cadr (symbol-function #'my/function))), but this notably fails on built-in C functions. I'm ...
4
votes
2answers
127 views

Calling a function with a shorter but unknown argument signature length

Is there a terse idiomatic way of calling a function in the manner of funcall (dereferencing function symbols) when that function may have a variably shorter function signature? Say for example: a ...
0
votes
1answer
77 views

converting xemacs lisp to run in emacs [closed]

I have used xemacs for years and have a lot of lisp code I have written. Now I want to switch to emacs and convert all the lisp code over to work in emacs. This is on an winXP machine. I'm sure I am ...
3
votes
2answers
250 views

An efficient set data structure in elisp

Does elisp provide a builtin efficient set data structure, similar to set in Python and std::set in C++?
3
votes
2answers
176 views

How to evaluate a symbol in a lambda function when defining it?

For example, (lambda () (message "%s" x))) But I would like x to be evaluated -- the lambda function should always use that value, instead of the current value of x. How should I do it? Preferably ...
1
vote
1answer
75 views

When is it not possible to quote nil? [duplicate]

I've never quoted nil before, as I can't see any sense in doing that, but I just played around with some code and it seems that in most cases it is possible to quote nil without any effect. However ...
12
votes
1answer
1k views

Meaning of period in (. 123)

I learnt . /path/to/file in bash is used to execute a file. Just out of curiosity, I eval something like the following in Emacs (. 123) ⇒ 123 (read "(. 123)") ⇒ 123 It looks like Emacs ...