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etc/LEDIT

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+Date: 17 Apr 85 15:45:42 EST (Wed)
+From: Martin David Connor <mdc@MIT-HTVAX.ARPA>
+
+    Date: Sat, 13 Apr 85 16:28:15 est
+    From: Richard M. Stallman <rms@mit-prep>
+
+    Can you help this person?  Also, can you give me the rest of ledit
+    to distribute, plus some info on how to use it?
+
+I have put the files "ledit.l" and "leditcfns.c" on prep:~mdc.
+Much to my disgust ledit.l relied on some bogus little package of
+functions on HT, so I had to massage it a bit.
+
+To get it to work, one must:
+
+   - Compile leditcfns.c with something like:
+
+     cc leditcfns.c
+
+   - Edit ledit.l, changing the line beginning "(cfasl" to 
+     have the right pathname for the cfns file you compiled in
+     the last step.
+
+   - Compile ledit.l with:
+
+     liszt ledit.l
+
+Then put the following lines in your .lisprc file:
+
+    ;load in functions for emacs interface
+    (load "//src//mdc//ledit//ledit")   ; Location of Ledit library
+    (set-proc-str "%gnumacs")		; Name of editor
+
+Then you can use ^E <RETURN> to get from LISP back to gnumacs.
+
+Here is the part of my .emacs file that pertains to ledit.
+
+    ;;; Set up ledit mode
+    (setq ledit-go-to-lisp-string "%lisp")
+    (setq lisp-mode-hook 'ledit-from-lisp-mode)
+
+    Date: Sat, 13 Apr 85 11:26:32 cst
+    From: neves@wisc-ai.arpa (David Neves)
+
+    This is a documentation question.
+    I cannot figure out how to use Ledit.  I suspect I need some
+    function on the Franz Lisp end of things to go to Emacs and read in
+    the temporary file.  Is this true?  Is the Lisp job started within
+    Emacs or outside of emacs?  I'm just plain confused.  Perhaps a couple
+    of words from someone in the know would help.
+
+    A related question.  I have been using a shell buffer when interacting
+    with Lisp (ie. put a definition in the kill buffer and then yank it
+    into the shell buffer to redefine it).  This is nice but tends to fill
+    up the shell buffer with lots of code (I'd rather keep calls to functions
+    in the shell and not the functions themselves).
+    My question:  Is using the shell buffer "better" than ledit?  Am I using
+    it in the best way (i.e. copying definitions from an edit buffer to the
+    shell buffer)?    -Thanks, David Neves
+
+I have found that ledit works well for doing programming development
+when you are changing lots of little pieces of a file and don't wish
+to recompile the whole file.  Of course M-X Compile is very nice for
+calling up a liszt on a buffer and watching it in the another window.
+Of course the interface of something like NIL is even better because
+you can compile your function directly into your lisp.  But since NIL
+doesn't run under Unix, this is probably the next best thing.
+
+I have tried the 2 window method (shell in lower window, lisp code in
+upper), and have found it a little awkward.  It does have certain
+advantages, but most of the time, I get be fine using M-C-D to save a
+defun for lisp, and C-X Z to jump back to LISP.  C-E RETURN from lisp 
+is also mnemonic for getting back to gnumacs.
+
+I hope this helps somewhat.
+
+

etc/ledit.l

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+;;; -*- Mode: lisp -*-
+
+; load in the c functions
+
+(removeaddress '_signal)
+(removeaddress '_switch_to_proc)
+(removeaddress '_set_proc_str)
+
+(cfasl "/src/mdc/ledit/leditcfns.o" '_switch_to_proc 'emacs)
+
+(getaddress '_set_proc_str 'set_proc_str)
+
+(declare (special *ledit-infile*               ; emacs->lisp tempfile
+		  *ledit-outfile*              ; lisp->emacs tempfile
+		  *ledit-ppfile*               ; pp->emacs tempfile
+                  *ledit-lisztfile*            ; compiler input
+                  *ledit-objfile*              ; compiler output
+		  *ledit-initialized*)         ; flag
+	 )
+
+(setq *ledit-initialized* nil)
+
+;;; INIT-LEDIT
+
+(defun init-ledit ()
+  (let ((user (getenv '|USER|)))		;USER must be uppercase
+       (setq
+	 *ledit-outfile* (concat "/tmp/" user ".l2") ; lisp -> emacs
+	 *ledit-infile*  (concat "/tmp/" user ".l1") ; emacs -> lisp
+	 *ledit-ppfile*  (concat "/tmp/" user ".l3") ; pp output to emacs.
+	 *ledit-lisztfile*  (concat "/tmp/" user ".l4")
+	 *ledit-objfile*  (concat "/tmp/" user ".o")
+	 *ledit-initialized* t)))
+
+;;; LEDIT
+; if 1 arg, arg is taken as a tag name to pass to emacs.
+; if 2 args, second arg is a keyword.  If 2nd arg is pp,
+; pp is applied to first arg, and result is sent to emacs
+; to put in a buffer called LEDIT (which is first erased.)
+
+(defun ledit fexpr (args)
+    (apply #'ledit* args))
+
+;;; LEDIT*
+
+(defun ledit* n
+    (if (not *ledit-initialized*) (init-ledit))
+    (ledit-output (listify n))
+    (syscall 10. *ledit-infile*)        ; syscall 10 is "delete"
+    (syscall 10. *ledit-lisztfile*)
+    (emacs)
+    (ledit-input)
+    (syscall 10. *ledit-outfile*)
+    (syscall 10. *ledit-ppfile*)
+    t)
+
+;;; LEDIT-OUTPUT
+;;; Egad, what a mess!  Doesn't work for XEMACS yet.
+;;; Here's an example from Mocklisp:
+;;; -> (defun bar (nothing) (bar nothing))
+;;; bar
+;;; -> (ledit bar)
+;;; should produce...
+;;; (progn) (progn tag (setq tag "bar") (&goto-tag))
+;;; and
+;;; -> (ledit bar pp)
+;;; should stuff this to emacs...
+;;; (progn) (switch-to-buffer "LEDIT") (erase-buffer)
+;;; (insert-file "/tmp/walter.l3") (lisp-mode)
+;;; and this...
+;;; (def bar
+;;;   (lambda (x)
+;;;    (bar nothing)))
+;;; into *LEDIT*
+
+(defun ledit-output (args)
+  (if args
+      (let ((ofile (outfile *ledit-outfile*)))
+	   (format ofile "(progn)")             ; this is necessary.
+
+	   (cond ((null (cdr args)) ; no keyword -> arg is a tag.
+		  (format ofile "(progn tag (setq tag \"~A\"~
+			         (&goto-tag))"
+			         (car args)))
+		 ((eq (cadr args) 'pp)       ; pp-> pp first arg to emacs
+		      (apply 'pp `((|F| ,*ledit-ppfile*) ,(car args)))
+		      (format ofile "(switch-to-buffer \"LEDIT\")~
+				     (erase-buffer)")
+		      (format ofile "(insert-file \"~A\")"
+			             *ledit-ppfile*)
+		      (format ofile "(lisp-mode)"))
+	   
+		 (t (format t "~&~A -- unknown option~%" (cdr args))))
+	   (close ofile))))
+
+;;; LISZT*
+;;; Need this guy to do compile-input.
+;;; Liszt returns 0 if all was well.
+;;; Note that in ordinary use the user will have to get used to looking
+;;; at "%Warning: ... Compiler declared *foo* special" messages, since
+;;; you don't usually want to hunt around in your file, zap in the the
+;;; declarations, then go back to what you were doing.
+;;; Fortunately this doesn't cause the compiler to bomb.
+;;; Some sleepless night I will think of a way to get around this.
+
+(defun liszt* (&rest args)
+   (apply #'liszt args))
+
+;;; LEDIT-INPUT
+;;; Although there are two cases here, in practice
+;;; it is never the case that there is both input to be
+;;; interpreted and input to be compiled.
+
+(defun ledit-input ()
+  (if (probef *ledit-lisztfile*)
+      (cond ((getd #'liszt)
+	     (format t ";Compiling LEDIT:")
+	     (and (zerop (liszt* *ledit-lisztfile* '-o *ledit-objfile*))
+		  (load *ledit-objfile*)))
+	    (t (format t ";Can't compile LEDIT: No liszt.~%;Reading instead:")
+	       (let ((ifile (infile *ledit-lisztfile*)))
+		 (ledit-load ifile)
+		 (close ifile)))))
+
+  (if (probef *ledit-infile*)
+      (let ((ifile (infile *ledit-infile*)))
+	(format t ";Reading from LEDIT:~%")
+	(ledit-load ifile)
+	(close ifile))))
+
+;;; LEDIT-LOAD
+;;; A generally useful form of load
+
+(defun ledit-load (ifile)
+  (let ((eof-form (list 'eof-form)))
+    (do ((form (read ifile eof-form) (read ifile eof-form)))
+      ((eq form eof-form))
+      (format t ";  ~A~%" (eval form)))))
+
+(setsyntax #/ 'macro 'ledit)                  ; make ^E = (ledit)<return>
+
+;; more robust version of the c function set_proc_str. Does argument checking.
+;; set_proc_str sets the string that is stuffed to the tty after franz pauses
+;; and the csh wakes up. It is usually "%emacs" or "%vemacs" or "%?emacs"
+(defun set-proc-str (arg)
+  (if (stringp arg)
+    (set_proc_str arg)
+    (if (symbolp arg)
+      (set_proc_str (get-pname arg))
+      (error arg " is illegal argument to set-proc-str"))))