Difference between revisions of "Emacs/Code folding"

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[[Category:Emacs|*]]
 
{{Haskell infobox}}
 
  
=== Folding ===
 
For folding parts of code you can use
 
*'''hide-show.el'''
 
*and '''hs-outline-level''' (based on py-outline-level created by Gb)
 
 
<code>
 
;; this gets called by outline to determine the level. Just use the length of the whitespace
 
  (defun hsk-outline-level ()
 
    (let (buffer-invisibility-spec)
 
      (save-excursion
 
        (skip-chars-forward "\t ")
 
        (current-column))))
 
 
;; this get called after haskell mode is enabled
 
    (add-hook
 
    'haskell-mode-hook
 
    (lambda ()
 
        ;; outline uses this regexp to find headers. I match lines with no indent and indented
 
        ;; some lines, such as "--" ... "class"
 
        (setq outline-regexp "^[^\t ].*\\|^.*[\t ]+\\(where\\|of\\|do\\|in\\|if\\|then\\|else\\|let\\|module\\|import\\|deriving\\|instance\\|class\\)[\t\n ]")
 
        ;; enable our level computation
 
          (setq outline-level 'hsk-outline-level)
 
        ;; do not use their \C-c@ prefix, too hard to type. Note this overides some python mode bindings
 
        ;;(setq outline-minor-mode-prefix "C-c")
 
        ;; turn on outline mode
 
          (outline-minor-mode t)
 
        ;; initially hide all but the headers
 
        ;;(hide-body)
 
        ))
 
</code>
 
 
*Also, you can use '''toggle-selective-display''' for global folding
 
 
<code>
 
;; folding for all rows, starting on the current column
 
    (defun toggle-selective-display (column)
 
      (interactive "P")
 
      (set-selective-display
 
      (or column
 
          (unless selective-display
 
            (1+ (current-column))))))
 
 
  (global-set-key (kbd "C-x $") 'toggle-selective-display)
 
 
    (defun toggle-hiding (column)
 
      (interactive "P")
 
      (if hs-minor-mode
 
          (if (condition-case nil
 
                  (hs-toggle-hiding)
 
                (error t))
 
              (hs-show-all))
 
        (toggle-selective-display column)))
 
 
  (global-set-key (kbd "C-@") 'toggle-hiding)
 
</code>
 
 
*and '''narrowing capabilities''' for folding the rest of code
 
<code>
 
    (put 'narrow-to-defun 'disabled nil)
 
    (put 'narrow-to-page 'disabled nil)
 
    (put 'narrow-to-region 'disabled nil)
 
</code>
 
 
*or '''folding-mode''', if you do not mind add markers such as '''{-{{{-}''' and '''{-}}}-}''' in code.
 

Revision as of 12:32, 11 April 2016