I want to be able to perform helm-swoop on an input error: on a compiler output buffer using C-x C-r, here is how I tried to achieve it.

(global-set-key (kbd "C-x C-r") (lambda () (interactive) (helm-swoop "error:")))

When I try to use it I get:

Keyword argument error: not one of (:$query :$source :$multiline)

I'm in a process of learning Emacs Lisp. Having this short cut would help speed up a workflow looking up compiler errors.


The (lambda () (interactive) ...) syntax is just fine. The problem you are encountering is with your invocation of helm-swoop. The arguments for that function must be keyed (preceded by their argument :keyword). C-h f shows that the signature is:

(helm-swoop &key $QUERY $SOURCE ($MULTILINE current-prefix-arg))

Try this:

(lambda (query)
  (interactive "sQuery: ")
  (helm-swoop :$query "error:"))

As @Tobias mentions, helm-swoop employs keyword arguments because it is defined by cl-defun. The cl-defun help page has a link to the cl info page "Argument Lists" which describes &key in more detail.

  • Thanks, you just made my day! Plain and simple answer. On the follow up: Is :$query a part of a language? I assume it is, but not sure. – A_P Sep 25 '18 at 12:46
  • 1
    Keywords are are self- quoting symbols that start with a ":" (so you don't need to use a "'" at the beginning). They are used for various things like denoting named/labeled arguments like that function. It occurred to me that you wanted to read user input. Try (lambda (query) (interactive "sQuery: ") ... ) – ebpa Sep 25 '18 at 12:56
  • 1
    Maybe mention that helm-swoop is defined by cl-defun. The help for cl-defun has a link to the cl info page for "keyword" arguments. – Tobias Sep 25 '18 at 14:31

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