Are there any #Lisp programmers out there who use a #ScreenReader? Given how messy Lisp can be to read without proper indentation (which I imagne wouldn't translate well on a screen reader) I can't see it is being an easy language to work in without being able to see it.

I've been thinking about a way to make an editor that lets you explore a Lisp program by walking through the forms in the program in a manner similar to the way one might navigate in a MUD. Is this a crazy idea, or one with some merit?

in reply to Jonathan Lamothe

Not to discourage new ways to solve old problems, I just want to point out that your lisp journey will be much easier if you use an editor designed for the task, which includes learning a set of editor operations that function at the "form"/s-exp level.

In emacs these operations include traversal functions like `forward-sexp`, and the very useful `indent-sexp` function. They're part of basic emacs behavior, you don't even need to do change emacs configuration to enable them, and they're useful on data other than lisp source code.

Once you can easily navigate up, down, and around forms, checking to see where a form starts and ends is easy without any sensitivity to how it's indented.

in reply to Jonathan Lamothe

Seemingly plain (lambda () ...) is a macro that expands to (function (lambda () ...)). #'(lambda () ...) uses a reader macro to expand to the same (function (lambda () ...)).

clhs.lisp.se/Body/m_lambda.htm

Function is a special operator that returns a function. It takes either a function name or a lambda expression. The second case is what is happening here.

clhs.lisp.se/Body/s_fn.htm#fun…

A lambda expression is a list of the symbol lambda, a lambda list, and a body.

clhs.lisp.se/Body/26_glo_l.htm…

elisp
God, my tab completion function is a hacky mess:
(defun lambdamoo-tab-complete ()
  "Complete user input using text from the buffer"
  (interactive)
  (when (memq (char-before) '(?  ?\r ?\n ?\t ?\v))
    (user-error "Point must follow non-whitespace character"))
  (let (replace-start
        (replace-end (point))
        replace-text found-pos found-text)
    (save-excursion
      (backward-word)
      (setq replace-start (point)
            replace-text (buffer-substring replace-start replace-end))
      (when (or (null lambdamoo--search-text)
                (not (string-prefix-p lambdamoo--search-text replace-text t)))
        (setq-local lambdamoo--search-text replace-text)
        (set-marker lambdamoo--found-point (point)))
      (goto-char lambdamoo--found-point)
      (unless
          (setq found-pos
                (re-search-backward
                 (concat "\\b" (regexp-quote lambdamoo--search-text))
                 (point-min) t))
        (setq-local lambdamoo--found-point (make-marker))
        (user-error "No match found"))
      (set-marker lambdamoo--found-point found-pos)
      (forward-word)
      (setq found-text (buffer-substring found-pos (point))))
    (delete-region replace-start replace-end)
    (insert found-text)))

#emacs #lisp #moo #mud #LambdaMOO

reshared this

elisp question

I'm certain I have reinvented a wheel here, but for the life of me I can't find it. Have I?

(defmacro jrl-extract-list (vars list &rest body)
  "Split a list into indiviual variables"
  (let ((list* (gensym)))
    (append
     `(let ,(cons (list list* list) vars))
     (seq-map (lambda (var)
                `(setq ,var (car ,list*)
                       ,list* (cdr ,list*)))
              vars)
     body)))

#emacs #lisp #elisp

Edit: Of course it was pcase.

elisp question

I just put a call to eval in my code and I feel dirty now.

The context went something like this:

(eval (cons 'concat (my-function arg1 arg2)))

I had initially hoped to use
(concat . (my-function arg1 arg2))

...but this resulted in a call to
(concat my-function arg1 arg2)

Which was not what I expected.

Is there a better way I could've written this?
#emacs #lisp #elisp

Edit: Got my answer. I wanted:

(apply 'concat (my-func arg1 arg2))

Edit 2:
It turns out the code I really wanted was:

(string-join arg2 arg1)

I love reinventing the wheel because I didn't know it was already there.

Edit 3:
Here's the actual code:

(defun lambdamoo-run-text-replacements (str)
  "Perform text replacements on the string"
  (dolist (vals lambdamoo-text-replacements)
    (let* ((from (car vals))
           (to (cdr vals))
           (split (split-string str from)))
      (setq str (string-join split to))))
  str)

Let's see if there's anything else I've reinvented here.

I just wrote a bunch of #elisp code like this:
(catch :abort
  ;; do something
  (when condition
    (message "A bad thing happened")
    (throw :abort nil))
  ;; do something else
  )

When the functionality I really wanted was:
(progn
  ;; do something
  (when condition
    (user-error "A bad thing happened"))
  ;; do something else
  )

I knew the former felt sketchy, but I couldn't think of a better way to do it until just now.
#emacs #lisp
in reply to Jonathan Lamothe

As a Schemer (and formerly/sometimes still Objective-C), everything is pretty verbose, and my own functions even more so, so I can search by function name knowing the type and parameters. (vector-index vec searchfunc), (draw-rect-with-edge-color rect edge-width color), etc.

There's no excuse for hardcore Lisp functions like (wadsf w q) "wander down stack frames for word query" (fictional but not unlikely).
#lisp

#lisp
in reply to Jonathan Lamothe

No no, the obarray you see from elisp is the same one used by the reader. Elisp is an old-style Lisp here, and the obarray is a first-class thing: you can make a new one, rebind obarray, etc.

That's the sort of thing people don't do much anymore, but used to do. The documentation covers it reasonably well gnu.org/software/emacs/manual/…

in reply to James Endres Howell

@James Endres Howell
I'm a little self-conscious about it as non-trivial is relative, but...
(defmacro lambdamoo-chatter-interact
    (func-name to msg docstring fmtstr &rest vals)
  "Define a function for interacting with another player"
  (let ((proc (gensym))
        (str (gensym)))
    `(defun ,func-name (,proc ,str)
       ,docstring
       (let ((,to lambdamoo-chatter)
             (,msg (substring-no-properties (lambdamoo-command-text ,str))))
         (if ,to
             (funcall lambdamoo-send-line ,proc
                      (format ,fmtstr . ,vals))
           (message "No chatter specified"))))))

Just spent a good half hour pulling my hair out trying to figure out why one of the #elisp functions I had just written was always returning nil when I tested it. Turns out, my test was mistakenly passing its inputs to the wrong (but similarly named) function (pivot-table-get-columns instead of pivot-table-get-body).

#Haskell's type system would've caught this. πŸ™ƒ

#emacs #lisp

in reply to Jonathan Lamothe

C's type system would also have caught it, and it isn't worth a hill of beans.

By caught it what do we mean? This is not a case of some undetected error escaping your attention due to dynamic typing. You know you got a nil which is unexpected and wrong. It's in a test case which catches it.

The only thing a type system would change is that you would instead waste a half hour not understanding how your obviously correct function call can possibly have the wrong return type.

I am in urgent job search mode, so I'm gonna throw this out here and see if anything comes of it.

I am a #Canadian, fluent in both #English and #French. I have experience with several programming languages. My strongest proficiency is with #Haskell and #C. I also have a reasonable grasp of #HTML, #JavaScript, #SQL, #Python, #Lua, #Linux system administration, #bash scripting, #Perl, #AWK, some #Lisp (common, scheme, and emacs), and probably several others I've forgotten to mention.

I am not necessarily looking for something in tech. I just need something stable. I have done everything from software development, to customer support, to factory work, though my current circumstances make in-person work more difficult than remote work. I have been regarded as a hard worker in every job I have ever held.

#GetFediHired

I've been an #Emacs user for like 20 years because there was one thing I needed to do back then that was made easier by elisp, and I just got used to using it. In all that time, I hardly ever tinkered much with the config, save a few minor tweaks it was pretty much stock. I had no strong feelings about Emacs in general, it was just the text editor I'd grown comfortable with.

I've recently been diving into #Lisp and poking around with my Emacs config, and after all these years, I think I'm starting to get the appeal. I am still a proponent of "use the tool that works for you", but I'm personally firmly on team Emacs now.

Julio Jimenez reshared this.

So, I've been taking another run at learning #CommonLisp. The last time I tried, I simply could not wrap my brain around macros. I'm reading the same book again, but this time am a more experienced programmer, and it all just clicked in my head.

I might actually end up enjoying #Lisp after all. I don't know if it'll dethrone #Haskell, but I'm starting to get why people like it.

reshared this

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