On Tue, Sep 17, 2019 at 8:46 AM John Kitchin <jkitchin@andrew.cmu.edu> wrote:
I don't totally understand what you are trying to do here.

I think the explanation was a little unclear!
 
If this were Python, it sounds like you want some kind of class that stores a variable and reuses it several different functions? Something kind of similar to that in elisp is a closure, which is like what you described. For example, here, we define a variable a, and then define two functions that use it persistently.


I think you can wrap this in a macro to make new functions, e.g. 

#+BEGIN_SRC emacs-lisp
(defmacro f-maker (a)
  `(lexical-let ((a ,a))
     (defun f1 (x)
       (* a x))

     (defun f2 (x)
       (+ a x))))

(f-maker 3)

(list (f1 2) (f2 2))
#+END_SRC

#+RESULTS:
| 6 | 5 |

This is basically what I want, except it turned out to be easier to just wrap the body forms in a let *within*the function.  THis is what I came up with:

#+BEGIN_SRC emacs-lisp

(defmacro dh-factory (name body &optional docstring)
"A helper macro that sets up the environment to simplify defining multiple functions with the same environment variables. NAME will bcome the functin name, BODY is a list containing the lisp forms specific to the function, and DOCSTRING is an optional ... docstring.  NAME wil lbe wrapped in a `let` statement setting all the remelvant variables."
  `(lexical-let (())
     (defun ,name ,()
       ,docstring
       (interactive)
       (let* ((gh (org-entry-get (point) "GITHUB"))
             (base (org-entry-get (point) "ORG_LMS_ASSIGNMENT_DIRECTORY"))
             (findFiles `( ,(concat "Reflection/" gh ".md") ,(concat "students/" gh ".json")))
             (browseFiles `( "index.html" ))
             (testOutput "TestResults/testresults.html")
             (testCommand "MARKING=instructor npm test"))
         ,@body))))

(dh-factory dh-find-files
            ((dolist (f findFiles)
               (message "%s" (concat base "/" f))
               (if (file-exists-p (concat base "/" f))
                   (find-file-other-window (concat base "/" f) )
                 (message "File %s does not exist, not opening." f)))  )
            "Open gradable files in Emacs windows")

(dh-factory dh-view
            ((loop for f in browseFiles
                    do
                    (browse-url-of-file (concat base "/" f ))))
            "open viewable files in browser")

;; this one should really pass a variable to allow different branches! oh well.  
(dh-factory dh-status
            ((magit-status base)
             (let ((currentBranch (shell-command-to-string
                                   (format "cd %s && git rev-parse --abbrev-ref HEAD" base) ))
                   (currentCommit (shell-command-to-string
                                   (format "cd %s && git rev-parse HEAD" base))))
               (magit-stash-worktree
                    (format "Stashed random files from %s after commit %s." currentBranch currentCommit)))
             (magit-checkout (concat gh "-master")))
            "Open a magit-status buffer and check out this student's branch in the repo")


(dh-factory dh-tests
            ((let ((output))
            (with-temp-buffer
               (message (concat "cd " base " ; npm test"))
               (setq output (shell-command-to-string (concat "cd " base " ; npm test"))))
            (message "WELL, sorta made it through: %s" output)
             (browse-url-of-file (concat base testOutput))))
            "Run tests directly from macs and view output")


#+END_SRC

I quite like it, though it's a bit unwieldy not to have the the source code available for edebug etc. It feels a little like having a namespace; I'm not afraid of  polluting the global namespace, but I can use these symbol names throughout the code I'm processing via the factory. 

I'm not sure it's *all* that much more efficient though...

There is also a class system you can probably use like this called eieio, Here is one approach to doing this.

#+BEGIN_SRC emacs-lisp
(require 'eieio)

(defclass Grade ()
  ((:a :initarg :a)))

(cl-defmethod gf1 ((g Grade) x)
  (* (oref g :a) x))

(cl-defmethod gf2 ((g Grade) x)
  (+ (oref g :a) x))

(let ((G (Grade :a 3)))
  (list (gf1 G 2) (gf2 G 2)))
#+END_SRC

#+RESULTS:
| 6 | 5 |

I would love to learn to use eieio but it feels like a bit of a jump.  

Finally, maybe the simplest thing to do is pass this information in as an argument, e.g. a plist or alist, or get them from a function that you only change in one place? 

That might have been more sensible but this was pretty fun!

Thanks everyone for the help! 



On Tue, Sep 17, 2019 at 7:31 AM Matt Price <moptop99@gmail.com> wrote:
I have a number of convenience functions define to help me with grading assignments. As I go through the semester, i update all of these functions modestly so that they'rehelpful for grading the current assignment. 

I big chunk of these simple functions is taken up just declaring variables with (let (())) forms.  Each function uses some ofhte same variables, e.g:

(defun dh-find-files ()
  (interactive)
  (let* ((base (org-entry-get (point) "ORG_LMS_ASSIGNMENT_DIRECTORY"))
         (gh (org-entry-get (point) "GITHUB"))
        (f2o `( ,(concat "Reflection/" gh ".md") ,(concat "students/" gh ".json")))) ;;;; "01/index.html" "02/index.html" "03/style.css" "04/style.css"
    (message "%s" f2o)
    ;; make more flexible for resubmits
    (shell-command (concat "cd " base " && git checkout " gh "-master"))
    (dolist (x f2o)
      (if (file-exists-p (concat base "/" x))
          (find-file-other-window (concat base "/" x) )
        (message "File %s does not exist, not opening." x)))))

(defun dh-tests ()
  (interactive)
  (let* ((base (org-entry-get (point) "ORG_LMS_ASSIGNMENT_DIRECTORY" ))
         (gh (org-entry-get (point) "GITHUB")))
    (with-temp-buffer (shell-command (concat "cd " base " && npm test") t)) ;; the "t" lets us suppress buffer
    (browse-url-of-file (concat base "/TestResults/testresults.html"))
    ;; (dh-mocha-run)
   
    ))

----------

This semester I changed some elements of my workflow and I had to update all the (org-entry-get) calls to new values.  It makes me think the code is less maintainable than it could be.  I would like to do something like this:

(lexical-let ((base `(org-entry-get (point) "ORG_LMS_ASSIGNMENT_DIRECTORY")
                   (gh `(org-entry-get (point) "GITHUB")) )
    (defun dh-find-files ()
(with-temp-buffer (shell-command (concat "cd " base " && npm test") t)) ;; the "t" lets us suppress buffer
    (browse-url-of-file (concat base "/TestResults/testresults.html")))))


Obviously it doesn't work this way. But is there any way to set macros like this to be expanded later inside a function definition? I feel certain there must be...

Thanks,

Matt