help-gnu-emacs
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: let*: Wrong type argument: stringp, nil


From: Hongyi Zhao
Subject: Re: let*: Wrong type argument: stringp, nil
Date: Wed, 29 Sep 2021 09:43:13 +0800

On Tue, Sep 28, 2021 at 4:02 PM Yuri Khan <yuri.v.khan@gmail.com> wrote:
>
> On Tue, 28 Sept 2021 at 10:08, Hongyi Zhao <hongyi.zhao@gmail.com> wrote:
>
> > Now I'm trying another test code snippet based on the idea posted here [1]:
> >
> >     (while (not (file-exists-p ".python-version"))
> >           (cd "..")
> >     ))
> >
> > But when I test the above code in scratch buffer, it seems to be stuck
> > in an endless loop and running there all the time. Any hints for this
> > problem?
>
> You’re not handling the case here that you reached the root directory
> without finding a .python-version file.
>
> You will really get better results if you use locate-dominating-file.
> If you’re trying to learn, learn by reading that function. As a bonus,
> it does not mess with the buffer’s default directory.

I work out the following code snippets using locate-dominating-file,
and it works as expected:

(defun try/pyvenv-workon ()
  (when (locate-dominating-file (buffer-file-name) ".python-version")
      
;https://emacs.stackexchange.com/questions/9474/let-statement-throws-error-on-assigning-a-form-to-a-variable
      (let ((file (concat (locate-dominating-file (buffer-file-name)
".python-version") ".python-version")))
           (pyvenv-workon (with-temp-buffer
                           (insert-file-contents file)
                             (nth 0 (split-string (buffer-string))))))))


BTW, should I use `let' or `let*' here?

HZ



reply via email to

[Prev in Thread] Current Thread [Next in Thread]