lisp

Is there a way to go back to last state of the runtime? In short, save the runtime and reload it. But the core image is too big (I'm making a small game :-), so I come up with an idea, save some important data, and start running at certain line (maybe also the stack info). For example: (defun save () _do-some-magic-to-save-the-state-and-then-exit_) (defvar data (list 'a 'b 'c)) ; important data (format t "Hello ") (save) (format t "World!~%") Next time, the software can start at the point where it stopped. $ software Hello $ software Hello $ software --load saved_state World! But I don't know

I was struggling with flattening a tree structure. I was doing it recursively by comparing each atomic symbol to the rest in the tree but, a friend of mine suggested the following code which I think looks cleaner. I just don't understand the line: ((atom tree)(list tree)) I understand what each of them do individually, I also know that the loop below takes a list or it causes an error, which I suspect has a lot to due with the reason we're turning the symbol into a list if atom returns true. But I still don't feel like I fully understand the code. (defun flatten (tree) (cond ((null tree) nil )

I was reading the book On Lisp by Paul Graham. In Chapter 4, Utility Functions, he gives examples of small functions that operate on lists, which would be helpful while writing a larger program. One of them is flatten . Given a nested list at any arbitrary level as argument, flatten will remove all the nested elements and put them on the top level. Below is my attempt at implementing flatten: (defun flatten (lst) (labels ((rflatten (lst1 acc) (dolist (el lst1) (if (listp el) (rflatten el acc) (push el acc))) acc)) (reverse (rflatten lst nil)))) But the above function does not flatten lists

I am attempting to write a function which compares two lists to see if they represent the same set. That is '(a b c d d) and '(d c b a d) represent the same set. The elements can be in any order. This is what I have, which works: (defun samesetp (list1 list2) (cond ((null list1) (null list2)) ((eq list2 (remove (car list1) list2 :count 1)) nil) (t (samesetP (cdr list1) (remove (car list1) list2 :count 1)))))) The reason I do not like this is that (remove (car list1) list2 :count 1)) is being computed twice - once to test if the remove operation truly removed anything, and once to recursively

I want to read multiple data files (10 in total) in Ansys Fluent. I wrote a journal file which uses scheme language (Do ((count 11.100 (+ count 0.100))) ((>= count 12.000)) (ti-menu-load-string (format #f "file read-data data-~a.dat" count))) The format of the file name is like data-11.200.dat , but the program reads it as data-11.2.dat . How I can force it to read the floating point numbers after the decimal point? Of course I can rename the data files, but that is not useful for I have to use the code many times. I have tried data-~03d.dat , but that didn't work! Try this: (do ((count 111/10