|
|
|
|
|
|
by neilv
1164 days ago
|
|
|
Two alternatives to also know about, if you're new to Emacs Lisp. * Lisp Interaction mode (like in your `scratch` buffer). Press `C-j` to eval the expression to left of the point, and insert the result in your buffer. Then you can leave the result there, edit it into a new code, undo to hide it, etc. * Emacs Lisp mode (like when you're editing any `.el` file) can also do a lot of things that people normally do in a REPL. Say, you're working on some code in the file, and it's running, and you want to change one of the functions. Just edit the function in the file, and hit `M-C-x` to evaluate the `defun` that the point is in, and see the value in the echo area. Or evaluate a region, or the entire file. (At one point, I also had a pretty-printer hooked up, so that it could do better transient display of values.) You can also selectively instrument functions for Edebug from here. This seems simple today, but it used to blow away the development languages and tools most people were using. |
|
|
* Eshell (launched with M-x eshell) is a shell in Emacs which uses a language that has elements from elisp. In particular, expressions in parentheses are evaluated as elisp forms [1]. Eshell is a shell (like e.g. bash), so it also has syntax to conveniently evaluate external commands, though it lacks some common shell functionality such as job control [2] and some types of redirection [3].
* Org Babel elisp source blocks [4,5]: In Org mode, use "#+begin_src elisp" and "#+end_src" to delimit lines with elisp and evaluate using C-c C-c, which will, by default, insert the result of the evaluation below the source block. This can be useful, if you want to keep a more organized record of the evaluated commands and their results in comparison to a REPL.
[1] https://www.gnu.org/software/emacs/manual/html_mono/eshell.h...
[2] https://www.gnu.org/software/emacs/manual/html_mono/eshell.h...
[3] https://www.gnu.org/software/emacs/manual/html_mono/eshell.h...
[4] https://orgmode.org/manual/Working-with-Source-Code.html
[5] https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-...