suggestion to add words of warning about cperl-mode to the wiki/documentation

[c-alpha]

cperl-mode is quite proactive about doing things automatically for you. It thus can, and often does, conflict with smartparens. I am thus proposing to add a few words of warning to the wiki and documentation about these possible interferences.

Thus, if when typing { in a Perl file, you get {}}, it's time to "tame cpel-mode". Here is the configuration I ended up using:

(use-package cperl-mode
  :init
  ;; cperl-mode is preferred to perl-mode
  ;; "Brevity is the soul of wit" <foo at acm.org>
  (defalias 'perl-mode 'cperl-mode)
  ;; un-bind the various parentheses as balancing is ensured by
  ;; smartparens, and these bindings would interfere
  :bind (:map cperl-mode-map
              ("{" . nil)
              ("[" . nil)
              ("(" . nil)
              ("}" . nil)
              ("]" . nil)
              (")" . nil))
  :custom
  (cperl-hairy t)
  (cperl-electric-parens nil "don't interfere with smartparens")
  (cperl-highlight-variables-indiscriminately t "highlight scalar variables, too"))

When you see similar "doubling-up issues" with other characters, check cperl-mode-map whether there are any further key bindings you might want to remove. Also see #323.

Hope this helps.

[c-alpha]

ping?

[Fuco1]

latex-mode does the same and there are mechanisms in smartparens to deal with this so that it "just works". I'll triage it and it will be fixed at some point.

[c-alpha]

Cool, many thanks for acting on this, @Fuco1 ! ❤️ 👍

[titanofold]

If helpful, here's the entirety of what I used to get satisfactory behavior.

(with-eval-after-load 'cperl-mode
  (setq cperl-invalid-face nil
    cperl-indent-parens-as-block t
    cperl-close-paren-offset (- cperl-indent-level)
        cperl-font-lock t
        cperl-electric-lbrace-space nil
        cperl-electric-parens nil
        cperl-electric-linefeed t
        cperl-electric-keywords t
        cperl-info-on-command-no-prompt t
        cperl-clobber-lisp-bindings t
        cperl-lazy-help-time 5)

  (define-key cperl-mode-map "{" nil)

  (with-eval-after-load 'smartparens
    (defun my-sp-cperl-indent (id action context)
      (cond ((eq context 'comment)
             (cperl-indent-for-comment))
            ((eq context 'code)
             (if (eq action 'wrap)
                 (cperl-indent-region
                  (sp-get sp-last-wrapped-region :beg)
                  (sp-get sp-last-wrapped-region :end))
               (cperl-indent-line)))))

    (sp-local-pair 'cperl-mode "{" nil :post-handlers '(:add my-sp-cperl-indent))))

Of particular interest is not enabling cperl-hairy and instead enable the specific features. Still, even without cperl-electric-parens, { gets bound so it needs to be unbound.

I'm not really certain what cperl-indent-for-comment does as nothing seems to change with comment indenting, but that is my preference.

At any rate, I get the correct number of braces/parens, and everything is indented nicely as I edit.

[Fuco1]

I added a page to the wiki with link back to this issue.