Another level of “next/previous” in the compilation buffer?

Question

I use Emacs with Cucumber (cucumber.io). Cucumber outputs lines like this:

Scenario: Jeff returns a faulty microwave              # /somepath/file1.feature:12
    Given Jeff has bought a microwave for $100         # /somepath/steps/file2.rb:5
    And he has a receipt
    When he returns the microwave
    Then Jeff should be refunded $100
          Exception blah
          /path/someotherdir/sourcefile.rb:123:error xxx occured

Scenario: Some other scenario...                       # /somepath/file1.feature:23
    Given ...

Everything works splendidly with the compilation buffers. I have made some entries in compilation-error-regexp-alist that locate those comments as "info" (in addition to whatever compiler/runtime errors from the Ruby environment) and am able to jump through everything.

Now, my question:

I would find it very handy if I could not only step between the "next" (M-n) and "previous" (M-p) steps in a completely linear fashion, but if I could separately do a "next scenario" (C-M-n) and "previous scenario" (C-M-p) binding. Those would ignore everything and just jump between the lines starting with Scenario:.

Is such a thing possible?

Answer 1

The shortcut for the next error is C-x ` (backquote, command next-error) and there is no keyboard shortcut for "previous-error".

Going to the next scenario seems totally doable with some keyboard macros or some elisp.

I'd try with macros first:

• start registering one (F3 or C-x ()
• go to the compilation buffer,
• search for the text "Scenario: ", visit it if needed,
• stop defining the macro (F4 or the closing parenthesis).

You can save it.

An elisp function would be nice though. I'd go with the same process (does it look right ?). I'll use M-x ielm to try things out and I'll search elisp methods in manuals and with the built-in help: C-x h k + a keypress to see the function that is called by this keyboard action.

The result will look grossely like:

(defun cucumber-next-scenario ()
    (interactive) ;; to call it with M-x
    (windmove-next-window)
    (search-forward "Scenario: ")
    ;; press enter ?
)

and… that's it ?

edit: function by the OP:

(defun my-previous-scenario () 
  (interactive) 
  "Jump to the previous cucumber scenario in the compilation buffer" 
  (switch-to-buffer-other-window "*compilation*") 
  (search-backward "Szenario:") 
  (execute-kbd-macro (kbd "<return>")))