LispForum

My daughter found Land of Lisp on my shelf and wants to learn Common Lisp. I approve of course, but for a 10-year old child I think the examples in the book are a bit too abstract. I'd like to start simple interactive graphics (create stuff from the REPL - instant satisfaction), but I have no luck ...

Stiv wrote:Hi all,

Sorry but I can't get current month .
How can I do it?

Thanks,
bye

I'm thinking you're going to want at least two of these functions: Look them up if you don't know what they are.

I would like to have a large global data structure (possibly a hash table, but not necessarily). I would like to have many functions add things to the structure, and look for things in the structure, getting references to internal structures. I would like to be able to periodically "clean up m...

As I use stumpwm (a common-lisp window manager), I normally always have a lisp process running. So I was wandering if there is a way I can use that instance to evaluate "scripts"? What I want to do is to write small lisp scripts and instead of executing them in their own separate instaces...

There's a website for exactly this kind of thing... Here you go: http://openhatch.org/ Though, Lisp pickings look rather slim. :( I checked out the projects you listed, and most do not indicate what kinds of help they need or where they plan to go in the future. It might be better to work either on ...

I like the idea of closures, though it is a bit above my pay-grade at the moment, Duke. I had another solution that used 'let' and 'dolist', but I didn't want to use setf. It must have been something I read somewhere about minimizing their usage. Is that just for a style of programming using Common...

Yeah, you want MAPCAR. What you do not want is #'LIST.
You'll also need one or two REDUCEs (or APPLYs) to get the sums.

Surprisingly, Alexandria's READ-FILE-INTO-STRING was only slightly faster than my wonky read-line/append function, and left unwanted newlines in the output. I think if I filter out the whitespace, the two will be pretty much equivalent. @Tom Thanks for the tip. I'll have to try that approach tomorrow.

Here's a closure, just for fun: (defun make-averager () (let ((numbers nil)) (lambda (lst) (setf numbers (nconc numbers lst)) (/ (apply #'+ numbers) (length numbers))))) CL-USER> (defvar pants (make-averager)) PANTS CL-USER> (funcall pants (list 1 2)) 3/2 CL-USER> (funcall pants (list 1 2)) 3/2 CL-U...

There doesn't seem to be a function analogous to C++'s stream insertion operator I think you meant stream extraction operator? Anyway, there is READ , except obviously since CL is dynamically typed it is not an exact equivalent, since it has to determine the type of the object solely from the repre...