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Constantine Vetoshev edited this page Aug 4, 2023 · 9 revisions

Workflow

Simple

The default workflow for Julia is to edit the code and then use julia-snail-send-buffer-file, julia-snail-send-region, or julia-snail-send-top-level-form to update the Julia process running in the REPL.

You would generally start by using julia-snail-send-buffer-file on the root file of your project, and proceed to use REPL-driven development as you see fit.

Revise

Revise is a popular tool for automatically updating the state of a Julia session. If you use it, then you no longer need to use julia-snail-send-buffer-file, julia-snail-send-region, or julia-snail-send-top-level-form. Snail is compatible with Revise: xref and autocomplete will work as expected as you modify your code.

NB: Revise requires careful use of julia-snail-update-module-cache. See the main documentation in the README for details.

(Refer to the discussion which prompted this section.)

Alternative Unicode substitution

There’s a [potentially] better way to insert unicode characters [than the default provided by julia-mode], and it’s xah-math-input. Basically, you type a (Roman) letter like "a", then shift-spc, and it substitutes the Greek equivalent, here α. Much better than \alpha then Tab, especially when you get to \varepsilon. Here’s a function that makes it work in the REPL as well:

(defun julia-snail--xah-math-substitute ()
  (interactive)
  (save-excursion
    (backward-char 1)
    (let ((newchar (xah-math-input--abbr-to-symbol (thing-at-point 'char t))))
      (forward-char 1)
      (vterm-send-backspace)
      (vterm-send-string newchar))))

and you can add

(define-key julia-snail-repl-mode-map (kbd "S-SPC") 'julia-snail--xah-math-substitute)

in your julia-snail-mode-hook to make it work.

company-mode integration

Snail usually tries to stick to stock Emacs facilities. In a few cases, it checks if a particular extra package is installed, and enables a little extra functionality.

If it detects company-mode, Snail begins loads docstrings for completion candidates and puts them in a documentation buffer. This documentation buffer can either be displayed in a window, or shown next to the completion interface using company-quickhelp.

If you find this too slow or annoying, you can turn off this behavior:

(customize-set-variable 'julia-snail-company-doc-enable nil)

Selectively disabling Snail features

If something in Snail does not fit your workflow, most of its Emacs integrations can be selectively disabled. Modify the following as desired:

(add-hook 'julia-snail-mode-hook
  (lambda ()
    (remove-hook 'completion-at-point-functions #'julia-snail-company-capf t)
    (remove-hook 'completion-at-point-functions #'julia-snail-repl-completion-at-point t)
    (remove-function (local 'eldoc-documentation-function) #'julia-snail-eldoc)
    (remove-hook 'xref-backend-functions #'julia-snail-xref-backend t)))

Copying a region into the REPL

Note
 This section is slightly outdated. julia-snail-send-region now copies code directly into the REPL when invoked with two prefix arguments (C-u C-u).

A suggestion about using the REPL a little more like a notebook:

The following function copies a region of code into the REPL like julia-snail-send-line, as opposed to julia-snail-send-region which uses the Snail network connection to evaluate the code.

(defun julia-snail-copy-repl-region ()
  "Copy the region (requires transient-mark) to the Julia REPL and evaluate it.
This is not module-context aware."
  (interactive)
  (if (null (use-region-p))
      (user-error "No region selected")
    (let* ((block-start (region-beginning))
           (block-end (region-end))
           (text (s-trim (buffer-substring-no-properties block-start block-end))))
      (julia-snail--send-to-repl text)
      (julia-snail--flash-region (point-at-bol) (point-at-eol)))))

Enabling JuliaSyntax in Julia <1.10

JuliaSyntax.jl is the new Julia parser in 1.10. It seems to cause problems when manually loaded in 1.9 and earlier, so please read the discussion here for tips on enabling it.

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