Category Archives: Emacs

Preventing Emacs from entering the debugger when a specific error occurs

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Emacs provides a built-in feature called debug-on-error, which can be activated with (setq debug-on-error t). The feature determines whether Emacs should enter the debugger when an error occurs. By default, Emacs enters the debugger for all errors, which can be helpful for diagnosing issues. However, there are cases where one may want to ignore specific errors that are not critical to their workflow.

Ignoring specific errors when (setq debug-on-error t) is activated

Open the Emacs configuration file, typically located at ~/.emacs or ~/.emacs.d/init.el. Then use the debug-ignored-errors variable to make Emacs ignore a specific error:

(add-to-list 'debug-ignored-errors 'specific-error-symbol)Code language: plaintext (plaintext)

Replace 'specific-error-symbol with the actual error that the specific function might raise.

Example

Suppose you encounter the search-failed error in Emacs (Evil package) when searching for a non-existent pattern:

Debugger entered--Lisp error: (search-failed "my-pattern")
  signal(search-failed ("my-pattern"))
  evil-ex-start-search(forward nil)
  evil-ex-search-forward(nil)
  funcall-interactively(evil-ex-search-forward nil)
  command-execute(evil-ex-search-forward)Code language: plaintext (plaintext)

To make Emacs ignore the search-failed error above, the following can be used:

(add-to-list 'debug-ignored-errors 'search-failed)Code language: plaintext (plaintext)

Emacs .dir-locals.el – Add project path to $PYTHONPATH (Python Development in Emacs)

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In order to ensure that the processes executed by Emacs and its packages, such as Flycheck or Flymake, can access the Python modules of a project, it is essential to correctly configure the $PYTHONPATH environment variable.

This article provides a solution by introducing a .dir-locals.el file that adds the directory path of .dir-locals.el to the $PYTHONPATH environment variable.

The .dir-locals.el file should be placed in the root directory of a Python project.

File name: .dir-locals.el

;; -*- mode: emacs-lisp; -*-
;; File: .dir-locals.el
;; Description:
;; This file adds the path where `.dir-locals.el` is located to the
;; `$PYTHONPATH` environment variable to ensure that processes executed by
;; Emacs and its packages, such as Flycheck or Flymake, can access the Python
;; modules of a project.
;;
;; Author: James Cherti
;; License: MIT
;; URL: https://www.jamescherti.com/emacs-dir-locals-add-path-to-pythonpath/

((python-mode . ((eval . (progn
                           (let ((project_path
                                  (car (dir-locals-find-file
                                        (buffer-file-name))))
                                 (python_path_env (getenv "PYTHONPATH")))
                             (setq-local process-environment
                                         (cons
                                          (concat "PYTHONPATH="
                                                  project_path
                                                  (if python_path_env
                                                      (concat ":" python_path_env)
                                                    ""))
                                          process-environment))))))))
Code language: Lisp (lisp)

Vim to Emacs: Converting code snippets from Ultisnips to YASnippet format

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(Information: There is also ultisnips-mode, an Emacs major mode for editing Ultisnips *.snippets files. This mode provides syntax highlighting to facilitate editing Ultisnips snippets.)

Ultyas is a command-line tool, written by James Cherti, designed to simplify the process of converting code snippets from Ultisnips (Vim) to YASnippet (Emacs) format. With Ultyas, you can effortlessly migrate your code snippets to the YASnippet format, saving you valuable time and effort.

Installation

Ultyas can be installed locally to ~/.local/bin/ultyas using pip:

pip install --user ultyasCode language: plaintext (plaintext)

Usage

You can convert Ultisnips snippets to the Yasnippet format by using the following command:

~/.local/bin/ultyas ~/.vim/UltiSnips/python.snippets -o ~/.emacs.d/snippets/python-mode/Code language: plaintext (plaintext)

Available command line options

Here are the available command line options for Ultyas:

usage: ultyas <file.snippets> -o <yasnippet-major-mode-dir>

A command-line tool for converting code snippets from Ultisnips to YASnippet format.

positional arguments:
  ultisnips_file        The Ultisnips .snippets file (e.g.
                        '~/.vim/UltiSnips/python.snippets')

options:
  -h, --help            show this help message and exit
  -o YASNIPPET_DIR, --yasnippet-dir YASNIPPET_DIR
                        The YASnippet snippets major mode directory (e.g.
                        '~/.emacs.d/snippets/python-mode/')
  -i {auto,fixed,nothing}, --yas-indent-line {auto,fixed,nothing}
                        Add one of the following comments to the YASnippet snippets that
                        will be generated: "# expand-env: ((yas-indent-line 'fixed))" or "#
                        expand-env: ((yas-indent-line 'auto))". For more information on
                        'yas-indent-line', visit:
                        https://joaotavora.github.io/yasnippet/snippet-reference.html#yas-
                        indent-line
  -t CONVERT_TABS_TO, --convert-tabs-to CONVERT_TABS_TO
                        Convert the tabs that are in the generated snippets to the string
                        passed to this option (Default: The indentation marker '$>')
  -v, --verbose         Verbose mode
  -q, --quiet           Quiet modeCode language: plaintext (plaintext)

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