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From: "Pascal J. Bourguignon" <pjb@informatimago.com>
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Subject: Re: Easier way to edit a splitted long string
Date: Fri, 04 Oct 2013 23:55:33 +0200
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Lele Gaifax <lele@metapensiero.it> writes:

> Hi all,
>
> I'm looking for an easier way to edit a "template", that is a long
> string representing a "prototype" text used to generate an HTML page,
> contained in JavaScript source.
>
> As an brief example, consider the following piece of code:
>
> {
>     xtype: 'container',
>     itemId: 'header',
>     tpl: [
>         '<div class="header">',
>         '    <div class="top">',
>         '        <div class="profession">{profession}</div>',
>         '        <span class="fullname">{fullname}</span>',
>         '        <span class="location">{city} &mdash; {country}</span>',
>         '        <span class="state">{state_label}</span>',
>         '    </div>',
>         '</div>'
>     ],
>     layout: {
>         type: 'hbox'
>     }
> },
>
> As you can see, the template is just a JS array of strings, one for each
> line: before use, all the strings are "joined" (that is, concatenated)
> together into a single big one.
>
> As you may imagine, editing the template as is is very boring! 
>
> Today, chatting with a friend about it, I had a flashback about some
> Emacs mode I used very long ago which I'm not able to find: it allowed
> to edit long C comments in a recursive edit, "stripping" away the "box"
> decoration (or just the start-comment and end-comment markers) as well
> as the text indentation on enter, and restoring the same kind of
> decoration on exit.
>
> Applied to my case, that would mean entering into a recursive edit
> buffer with the following content:
>
> <div class="header">
>     <div class="top">
>         <div class="profession">{profession}</div>
>         <span class="fullname">{fullname}</span>
>         <span class="location">{city} &mdash; {country}</span>
>         <span class="state">{state_label}</span>
>     </div>
> </div>
>
> It does not seem so difficult to achieve (even for an elisp newbie as I
> am) and I could give it a try, but I wonder if something similar already
> exists.

Yes, something similar already exists.

It's a little more complex than what you need, but I guess it'll be a
good example.


In some CASE tool, there's this 'J' scripting language that let you
evaluate code that's stored in strings, but that doesn't have functions
and function calls. (Yeah, silly isn't it!  Why couldn't they just use
lisp as any sane application would do, from emacs to autocad).  Anyways,
imagine having to edit "subroutines" in strings like this (where ~ is
the escape character):


// FUNCTION: computeCxxClassName
// Given the pathName of a class, computes the fully qualified C++
// name, ignoring the packages that have the C++NoNameSpace tag.
// EXAMPLE: classPathName=other.OwnerClass.pathName;eval(computeCxxClassName);otherClassName=cxxClassName;
String computeCxxClassName=" this{ Package currentPackage=rootPackage; string sep=~"~"; string s=classPathName; string[] items=s.segment(~":~"); int i; cxxClassName=~"~"; for(i=1; i<items.size()-1; i=i+1){ this{ Package subPackage; string item; boolean found=false; getItemSet(items,i,item); StdErr.write(item,NL); subPackage=currentPackage.getPackageByName(item); subPackage.TagTaggedValue.<while(not(found)){ getTagType().<while(not(found)){ found=Name==~"C++NoNameSpace~"; } } if(not(found)){ cxxClassName=cxxClassName+sep+subPackage.Name; sep=~"::~"; } currentPackage=subPackage; } } this{ string item; getItemSet(items,items.size()-1,item); cxxClassName=cxxClassName+sep+item; } } ";
// PARAMETERS:
String           classPathName;                              // input    
String           cxxClassName;                               // output   
// END FUNCTION


Ah, right, here I already added some comments, to add some information
to the bare string variable definition.  This let me implement a parser
with access to all the information needed to generate the following
code, which is much more readable, and foremost, much more editable!


function computeCxxClassName(input    String           classPathName,
                             output   String           cxxClassName)
// Given the pathName of a class, computes the fully qualified C++
// name, ignoring the packages that have the C++NoNameSpace tag.
// EXAMPLE: classPathName=other.OwnerClass.pathName;eval(computeCxxClassName);otherClassName=cxxClassName;
{
 this{
      Package currentPackage=rootPackage;
      string sep="";
      string s=classPathName;
      string[] items=s.segment(":");
      int i;
      cxxClassName="";
      for(i=1;
          i<items.size()-1;
          i=i+1){
                 this{
                      Package subPackage;
                      string item;
                      boolean found=false;
                      getItemSet(items,i,item);
                      StdErr.write(item,NL);
                      subPackage=currentPackage.getPackageByName(item);
                      subPackage.TagTaggedValue.<while(not(found)){
                                                                   getTagType().<while(not(found)){
                                                                                                   found=Name=="C++NoNameSpace";
                                                                                                   }
                                                                   }
                      if(not(found)){
                                     cxxClassName=cxxClassName+sep+subPackage.Name;
                                     sep="::";
                                     }
                      currentPackage=subPackage;
                      }
                 }
      this{
           string item;
           getItemSet(items,items.size()-1,item);
           cxxClassName=cxxClassName+sep+item;
           }
      }
}


and of course, there's the inverse command, to transform this language
back into the string definitions.  Here is the code of explode-j-region
and implode-j-region.  Of course, doing something similar to your
strings, (and adding a narrow-to-region / widden with possibly a change
of mode to let you concentrate on editing the html templates), will be
trivial compared to this example which involves parsers; I'll leave it
up to you, as a good learning exercise.



;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; J macros utilities
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(defun implode-j-string (source)
  "Return a string containing a J string containing the J source code,
properly escaped.."
  (with-temp-buffer
    (insert source)
    (goto-char (point-min))             ; remove // comments
    (while (and (< (point) (point-max))
                (re-search-forward "^\\([^\"/]\\|\"\\([^\"~]\\|~.\\)*\"\\|/[^/]\\)*\\(//.*\\)$" (point-max) t))
      (with-marker (current (match-end 3))
        (delete-region (match-beginning 3) current)
        (goto-char current)) 
      (beginning-of-line 1))
    (goto-char (point-min))             ; remove spaces before
    (while (and (< (point) (point-max)) (re-search-forward "^ +" (point-max) t))
      (delete-region (match-beginning 0) (match-end 0)))
    (goto-char (point-min))          ; escape double-quotes and tildes
    (while (and (< (point) (point-max)) (re-search-forward "[\"~]" (point-max) t))
      (goto-char (match-beginning 0))
      (insert "~")
      (forward-char 1))
    (goto-char (point-min))             ; remove newlines
    (while (and (< (point) (point-max)) (search-forward "\n" (point-max) t))
      (delete-region (match-beginning 0) (match-end 0))
      (insert " "))
    (buffer-substring (point-min) (point-max))))


(defun explode-j-string (jstr)
  "Returns a string containing properly formated J code extracted from the JSTR."
  (with-temp-buffer
    (loop
       with state = 'out
       for ch across jstr
       do (case state
            ((init)
             (case ch
               ((?\") (setf state 'out))
               (otherwise
                (error "Unexected character %c at start fo j string" ch))))
            ((out)
             (case ch
               ((?\{) (insert "{\n"))
               ((?\;) (insert ";\n"))
               ((?\}) (insert "}\n"))
               (otherwise (insert ch))))
            ((escaped)
             (insert ch)
             (setf state 'out)))
       finally (progn (java-mode)
                      (indent-region (point-min) (point-max))
                      (return (buffer-substring (point-min) (point-max)))))))


(defun make-j-string (start end)
  (interactive "r")
  (let ((source (buffer-substring-no-properties start end)))
    (with-marker (end end)
      ;; 1- comment out the original source.
      (comment-region start end)
      (goto-char end)
      (insert "\nString xxx=" (implode-j-string source) ";\n"))))


(defstruct jfun start end name comments string parameters)
(defstruct jpar type name initial-value mode comment)


(defun string-prune-left (trim-bag skip-bag string)
  (loop for i from 0 below (length string)
     while (position (aref string i) trim-bag)
     finally (progn (when (and (< i (length string)) (position (aref string i) skip-bag))
                      (incf i))
                    (return (subseq string i)))))

(defun string-prune-right (trim-bag skip-bag string)
  (loop for i from (1- (length string))  downto 0
     while (position (aref string i) trim-bag)
     finally (progn (when (and (< 0 i) (position (aref string i) skip-bag))
                      (decf i))
                    (return (subseq string 0 (1+ i))))))



(defun* get-imploded-j-function-before-point (point)
  "Returns the jfun structure describing the J function found before the point."
  (macrolet ((abort (message &rest args)
               `(progn
                  (message ,message ,@args)
                  (return-from get-imploded-j-function-before-point nil)))
             (check (condition message &rest args)
               `(unless ,condition
                  (abort ,message ,@args))))
    (forward-line 1)
    (check (re-search-backward "^// FUNCTION: " (point-min) t)
           "No // FUNCTION: header.")
    (let ((fun (make-jfun :start (point))))
      (goto-char (match-end 0))
      (c-skip-ws-forward (line-end-position))
      (check (setf (jfun-name fun) (symbol-at-point))
             "Can't find a J function name after // FUNCTION: ")
      (forward-line 1) (beginning-of-line)
      (setf (jfun-comments fun)
            (loop while (looking-at "//")
               collect (string-trim " " (buffer-substring-no-properties
                                         (+ 2 (line-beginning-position))
                                         (line-end-position)))
               do (forward-line 1)))
      (check (looking-at "String ")
             "Can't find a String %s declaration for function %s"
             (jfun-name fun) (jfun-name fun))
      (forward-sexp 1) (c-skip-ws-forward)
      (check (eql (jfun-name fun) (symbol-at-point))
             "Different J function name in String %s declaration vs. // FUNCTION: %s"
             (symbol-at-point) (jfun-name fun))
      (forward-sexp 1) (c-skip-ws-forward)
      (check (looking-at "=") "Expected a = after String %s" (jfun-name fun))
      (forward-char 1) (c-skip-ws-forward)
      (setf (jfun-string fun)
            (loop
               with state = 'init
               with result = '()
               for ch = (prog1 (aref (buffer-substring-no-properties (point) (1+ (point))) 0)
                          (forward-char 1))
               do (ecase state
                    ((init)
                     (case ch
                       ((?\") (setf state 'string))
                       (otherwise
                        (abort "Invalid character %c, expected a string" ch))))
                    ((string)
                     (case ch
                       ((?\~) (setf state 'escape))
                       ((?\") (setf state 'done))
                       (otherwise (push ch result))))
                    ((escape)
                     (push ch result)
                     (setf state 'string)))
               until (eq state 'done)
               finally (return (coerce (nreverse result) 'string))))
      (c-skip-ws-forward)
      (check (looking-at ";")
             "Expected a ; after the string in // FUNCTION: %s" (jfun-name fun))
      (forward-line 1) (beginning-of-line)
      (when (looking-at "// PARAMETERS:")
        (forward-line 1) (beginning-of-line)
        (let ((pars '()))
          (while (let ((case-fold-search t))
                   (looking-at
                    (concat " *"
                            "\\([A-Za-z][A-Z0-9a-z]*\\(\\[\\]\\)?\\) +"
                            "\\([A-Za-z][A-Z0-9a-z]*\\) *"
                            "\\(= *\\(\\([^/]\\|/[^/]\\)*\\)\\)?; *"
                            "\\(// *"
                            "\\(input\\|output\\|inout\\|constant\\) +"
                            "\\(.*\\)?"
                            "\\)?$")))
            (push (make-jpar :type (match-string 1)
                             :name (match-string 3)
                             :initial-value (match-string 5)
                             :mode  (string-downcase (or (match-string 8) "inout"))
                             :comment (match-string 9)) pars)
            (forward-line 1)
            (beginning-of-line))
          (setf (jfun-parameters fun) (nreverse pars))))
      (check (looking-at "// END FUNCTION")
             "Expected // END FUNCTION at the end of the // FUNCTION: %s"
             (jfun-name fun))
      (forward-line 1) (beginning-of-line)
      (setf (jfun-end fun) (point))
      fun)))


(defun* get-exploded-j-function-before-point (point)
  "Returns the jfun structure describing the J function found before the point."
  (macrolet ((abort (message &rest args)
               `(progn
                  (message ,message ,@args)
                  (return-from get-exploded-j-function-before-point nil)))
             (check (condition message &rest args)
               `(unless ,condition
                  (abort ,message ,@args))))
    (forward-line 1)
    (check (re-search-backward "^function " (point-min) t)
           "No function header.")
    (let ((fun (make-jfun :start (point))))
      (goto-char (match-end 0))
      (c-skip-ws-forward (line-end-position))
      (check (setf (jfun-name fun) (symbol-at-point))
             "Can't find a J function name after function ")
      (forward-sexp 1)
      (check (looking-at "(")
             "Missing argument list in function %s" (jfun-name fun))
      (forward-char 1)
      (if (looking-at "[ \n]*)")
          (progn
            (goto-char (match-end 0))
            (forward-line 1)
            (beginning-of-line)
            (setf (jfun-parameters fun) '()))
          (let ((pars '())
                (done nil))
            (while (and (not done)
                        (let ((case-fold-search t))
                          (looking-at
                           (concat " *"
                                   "\\(input\\|output\\|inout\\|constant\\) +"
                                   "\\([A-Za-z][A-Z0-9a-z]*\\(\\[\\]\\)?\\) +"
                                   "\\([A-Za-z][A-Z0-9a-z]*\\) *"
                                   "\\(= *\\(\\([^/\n]\\|/[^/\n]\\)*\\)\\)?"
                                   "\\([,)]\\) *"
                                   "\\(//\\(.*\\)\\)?"))))
              (push (make-jpar :type (match-string 2)
                               :name (match-string 4)
                               :initial-value (match-string 6)
                               :mode (string-downcase (match-string 1))
                               :comment (match-string 10)) pars)
              (setf done (string= (match-string 6) ")"))
              (forward-line 1)
              (beginning-of-line))
            (setf (jfun-parameters fun) (nreverse pars))))
      (setf (jfun-comments fun)
            (loop while (looking-at "//")
               collect (string-trim " " (buffer-substring-no-properties
                                         (+ 2 (line-beginning-position))
                                         (line-end-position)))
               do (forward-line 1)))
      (c-skip-ws-forward)
      (let ((start (point)))
        (forward-sexp 1)
        (setf (jfun-string fun)
              (string-prune-right
               " " "}" (string-prune-left
                        " "  "{"
                        (implode-j-string (buffer-substring-no-properties start (point)))))))
      (setf (jfun-end fun) (point))
      fun)))


(defun insert-imploded-j-function (fun)
  "Insert a jfun with the imploded syntax:
 // FUNCTION: ... String ...=...; // PARAMETERS ... // END FUNCTION"
  (let ((start (point)))
    (insert (format "// FUNCTION: %s\n" (jfun-name fun)))
    (dolist (line (jfun-comments fun))
      (insert (format "// %s\n" line)))
    (insert (format "String %s=\"%s\";\n" (jfun-name fun) (jfun-string fun)))
    (insert "// PARAMETERS:\n")
    (dolist (par (jfun-parameters fun))
      (let ((decl  (format "%-16s %s" (jpar-type par) (jpar-name par))))
        (setf decl (if (jpar-initial-value par)
                       (format "%-38s=%s;" decl (jpar-initial-value par))
                       (format "%s;" decl)))
        (insert (format "%-60s // %-8s " decl (jpar-mode par))))
      (when (and (jpar-comment par) (string< "" (jpar-comment par)))
        (insert (jpar-comment par)))
      (insert "\n"))
    (insert "// END FUNCTION\n")))


(defun insert-exploded-j-function (fun)
  "Insert a jfun with the exploded syntax: function ...(...){...}"
  (let ((start (point)))
    (insert (format "function %s(" (jfun-name fun)))
    (flet ((insert-par (par sep)
             (let ((base (format "%-8s %-16s %s%s%s"
                                 (jpar-mode par) (jpar-type par) (jpar-name par)
                                 (if (jpar-initial-value par)
                                     (format "=%s" (jpar-initial-value par))
                                     "")
                                 sep)))
               (insert (if (and (jpar-comment par) (string< "" (jpar-comment par)))
                           (format "%-50s // %s\n" base (jpar-comment par))
                           (format "%s\n" base))))))
      (let ((pars (jfun-parameters fun)))
        (if pars
            (progn
              (dolist (par (butlast pars))
                (insert-par par ","))
              (insert-par (car (last pars)) ")"))
            (insert ")\n"))))
    (dolist (line (jfun-comments fun))
      (insert (format "// %s\n" line)))
    (insert "{\n")
    (insert (explode-j-string (jfun-string fun)))
    (insert "}\n")
    (indent-region start (point))))



(defun implode-last-j-function (point)
  "Transform the  function ...(...) {...} J function preceding the point
into a // FUNCTION: ... // END FUNCTION section."
  (interactive "d")
  (let ((fun (get-exploded-j-function-before-point point)))
    (when fun
      (delete-region (jfun-start fun) (jfun-end fun))
      (insert-imploded-j-function fun)
      t)))


(defun explode-last-j-function (point)
  "Transform the // FUNCTION: ... // END FUNCTION section preceding the point
into a function ...(...) {...} J function."
  (interactive "d")
  (let ((fun (get-imploded-j-function-before-point point)))
    (when fun
      (delete-region (jfun-start fun) (jfun-end fun))
      (insert-exploded-j-function fun)
      t)))



(defun implode-j-region (start end)
  (interactive "r")
  (goto-char end)
  (while (and (< start (point))
              (implode-last-j-function (point)))))


(defun implode-j-buffer ()
  (interactive)
  (implode-j-region (point-min) (point-max)))



(defun explode-j-region (start end)
  (interactive "r")
  (goto-char end)
  (while (and (< start (point))
              (explode-last-j-function (point)))))


(defun explode-j-buffer ()
  (interactive)
  (explode-j-region (point-min) (point-max)))

(defun trace-j-expressions (start end)
  (interactive "r")
  (goto-char start)
  (with-marker (end end)
    (let* ((es)
           (ee)
           (expression (progn (forward-sexp 1)
                              (setf ee (point))
                              (backward-sexp 1)
                              (setf es (point))
                              (buffer-substring-no-properties es ee))))
      (while (< ee end)
        (delete-region es ee)
        (insert (format "StdErr.write(\"%s = \",%s,NL);" expression expression))
        (setf expression (progn (forward-sexp 1)
                                (setf ee (point))
                                (backward-sexp 1)
                                (setf es (point))
                                (buffer-substring-no-properties es ee)))))))



(defun jmp-compile-buffer ()
  (interactive)
  (let ((jmp-file-name (buffer-file-name)))
    (cond
      ((null jmp-file-name)
        (error "Buffer %S has no file name. Expected a .jmp file."
               (buffer-name)))
      ((not (string-match "^\\(.*\\)\\.jmp$" jmp-file-name))
       (error "Buffer %S isn't a .jmp file buffer." (buffer-name)))
      (t (let ((jml-file-name (format "%s.jmf" (match-string 1 jmp-file-name)))
               (jmp-source (buffer-string)))
           (find-file jml-file-name)
           (erase-buffer)
           (insert jmp-source)
           (implode-j-buffer)
           (save-buffer 0)
           (kill-buffer (current-buffer)))))))

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-- 
__Pascal Bourguignon__
http://www.informatimago.com/