* clear out some warnings by gcc 9.3.1.

[alpine.git] / pico / basic.c

#if     !defined(lint) && !defined(DOS)
static char rcsid[] = "$Id: basic.c 831 2007-11-27 01:04:19Z hubert@u.washington.edu $";
#endif

/*
 * ========================================================================
 * Copyright 2006-2007 University of Washington
 * Copyright 2013-2020 Eduardo Chappa
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * ========================================================================
 *
 * Program:     Cursor manipulation functions
 */

/*
 * The routines in this file move the cursor around on the screen. They
 * compute a new value for the cursor, then adjust ".". The display code
 * always updates the cursor location, so only moves between lines, or
 * functions that adjust the top line in the window and invalidate the
 * framing, are hard.
 */
#include        "headers.h"

#include "osdep/terminal.h"


/*
 * Move the cursor to the
 * beginning of the current line.
 * Trivial.
 */
int
gotobol(int f, int n)
{
    curwp->w_doto  = 0;
    return (TRUE);
}

/*
 * Move the cursor backwards by "n" characters. If "n" is less than zero call
 * "forwchar" to actually do the move. Otherwise compute the new cursor
 * location. Error if you try and move out of the buffer. Set the flag if the
 * line pointer for dot changes.
 */
int
backchar(int f, int n)
{
    register LINE   *lp;

    if (n < 0)
      return (forwchar(f, -n));

    while (n--) {
        if (curwp->w_doto == 0) {
            if ((lp=lback(curwp->w_dotp)) == curbp->b_linep){
                if(Pmaster && Pmaster->headents)
                    /*
                     * go up into editing the mail header if on 
                     * the top line and the user hits the left arrow!!!
                     *
                     * if the editor returns anything except -1, the 
                     * user requested something special, so let 
                     * pico know...
                     */
                  return(HeaderEditor(2, 1));
                else
                  return (FALSE);
            }

            curwp->w_dotp  = lp;
            curwp->w_doto  = llength(lp);
            curwp->w_flag |= WFMOVE;
        } else
          curwp->w_doto--;
    }

    return (TRUE);
}

/*
 * Move the cursor backwards by "n" characters. If "n" is less than zero call
 * "forwchar" to actually do the move. Otherwise compute the new cursor
 * location. Error if you try and move out of the buffer. Set the flag if the
 * line pointer for dot changes.
 *
 * This routine does _not_ do the header editor checks. It is used by
 * backword() in pico\word.c which gets stuck in a loop trying to go
 * back if you've jumped into a header.
 */
int
backchar_no_header_editor(int f, int n)
{
    register LINE   *lp;

    if (n < 0)
      return (forwchar(f, -n));

    while (n--) {
        if (curwp->w_doto == 0) {
            if ((lp=lback(curwp->w_dotp)) == curbp->b_linep){
                  return (FALSE);
            }

            curwp->w_dotp  = lp;
            curwp->w_doto  = llength(lp);
            curwp->w_flag |= WFMOVE;
        } else
          curwp->w_doto--;
    }

    return (TRUE);
}

/*
 * Move the cursor to the end of the current line. Trivial. No errors.
 */
int
gotoeol(int f, int n)
{
    curwp->w_doto  = llength(curwp->w_dotp);
    return (TRUE);
}


/*
 * Move the cursor forwwards by "n" characters. If "n" is less than zero call
 * "backchar" to actually do the move. Otherwise compute the new cursor
 * location, and move ".". Error if you try and move off the end of the
 * buffer. Set the flag if the line pointer for dot changes.
 */
int
forwchar(int f, int n)
{
    if (n < 0)
      return (backchar(f, -n));

    while (n--) {
        if (curwp->w_doto == llength(curwp->w_dotp)) {
            if (curwp->w_dotp == curbp->b_linep)
              return (FALSE);

            curwp->w_dotp  = lforw(curwp->w_dotp);
            curwp->w_doto  = 0;
            curwp->w_flag |= WFMOVE;
        }
        else
          curwp->w_doto++;
    }
    
    return (TRUE);
}


/*
 * move to a particular line.
 * argument (n) must be a positive integer for
 * this to actually do anything
 */
int
gotoline(int f, int n)
{
    if (n < 1)          /* if a bogus argument...then leave */
      return(FALSE);

    /* first, we go to the start of the buffer */
    curwp->w_dotp  = lforw(curbp->b_linep);
    curwp->w_doto  = 0;
    return(forwline(f, n-1));
}


/*
 * Goto the beginning of the buffer. Massive adjustment of dot. This is
 * considered to be hard motion; it really isn't if the original value of dot
 * is the same as the new value of dot. Normally bound to "M-<".
 */
int
gotobob(int f, int n)
{
    curwp->w_dotp  = lforw(curbp->b_linep);
    curwp->w_doto  = 0;
    curwp->w_flag |= WFHARD;
    return (TRUE);
}


/*
 * Move to the end of the buffer. Dot is always put at the end of the file
 * (ZJ). The standard screen code does most of the hard parts of update.
 * Bound to "M->".
 */
int
gotoeob(int f, int n)
{
    curwp->w_dotp  = curbp->b_linep;
    curwp->w_doto  = 0;
    curwp->w_flag |= WFHARD;
    return (TRUE);
}


/*
 * Move forward by full lines. If the number of lines to move is less than
 * zero, call the backward line function to actually do it. The last command
 * controls how the goal column is set. Bound to "C-N". No errors are
 * possible.
 */
int
forwline(int f, int n)
{
    register LINE   *dlp;

    if (n < 0)
      return (backline(f, -n));

    if ((lastflag&CFCPCN) == 0)             /* Reset goal if last   */
      curgoal = getccol(FALSE);       /* not C-P or C-N       */

    thisflag |= CFCPCN;
    dlp = curwp->w_dotp;
    while (n-- && dlp!=curbp->b_linep)
      dlp = lforw(dlp);

    curwp->w_dotp  = dlp;
    curwp->w_doto  = getgoal(dlp);
    curwp->w_flag |= WFMOVE;
    return (TRUE);
}


/*
 * This function is like "forwline", but goes backwards. The scheme is exactly
 * the same. Check for arguments that are less than zero and call your
 * alternate. Figure out the new line and call "movedot" to perform the
 * motion. No errors are possible. Bound to "C-P".
 */
int
backline(int f, int n)
{
    register LINE   *dlp;

    if (n < 0)
      return (forwline(f, -n));

    if(Pmaster && Pmaster->headents){
        /*
         * go up into editing the mail header if on the top line
         * and the user hits the up arrow!!!
         */
        if (lback(curwp->w_dotp) == curbp->b_linep)
          /*
           * if the editor returns anything except -1 then the user
           * has requested something special, so let pico know...
           */
          return(HeaderEditor(1, 1));
    }

    if ((lastflag&CFCPCN) == 0)             /* Reset goal if the    */
      curgoal = getccol(FALSE);       /* last isn't C-P, C-N  */

    thisflag |= CFCPCN;
    dlp = curwp->w_dotp;
    while (n-- && lback(dlp)!=curbp->b_linep)
      dlp = lback(dlp);

    curwp->w_dotp  = dlp;
    curwp->w_doto  = getgoal(dlp);
    curwp->w_flag |= WFMOVE;
    return (TRUE);
}


/*
 * go back to the beginning of the current paragraph
 * here we look for a <NL><NL> or <NL><TAB> or <NL><SPACE>
 * combination to delimit the beginning of a paragraph  
 */
int
gotobop(int f, int n)
{
    int quoted, qlen;
    UCS qstr[NLINE], qstr2[NLINE];

    if (n < 0)  /* the other way...*/
      return(gotoeop(f, -n));

    while (n-- > 0) {   /* for each one asked for */

        while(lisblank(curwp->w_dotp)
              && lback(curwp->w_dotp) != curbp->b_linep){
            curwp->w_dotp = lback(curwp->w_dotp);
            curwp->w_doto = 0;
        }
        
        /* scan line by line until we come to a line ending with
         * a <NL><NL> or <NL><TAB> or <NL><SPACE>
         *
         * PLUS: if there's a quote string, a quoted-to-non-quoted
         *       line transition.
         */
        quoted = quote_match(glo_quote_str, curwp->w_dotp, qstr, NLINE);
        qlen   = quoted ? ucs4_strlen(qstr) : 0;
        while(lback(curwp->w_dotp) != curbp->b_linep
              && llength(lback(curwp->w_dotp)) > qlen
              && quoted == quote_match(glo_quote_str,
                                           lback(curwp->w_dotp),
                                           qstr2, NLINE)
              && !ucs4_strcmp(qstr, qstr2)
              && lgetc(curwp->w_dotp, qlen).c != TAB
              && lgetc(curwp->w_dotp, qlen).c != ' ')
          curwp->w_dotp = lback(curwp->w_dotp);

        if(n){
            /* keep looking */
            if(lback(curwp->w_dotp) == curbp->b_linep)
              break;
            else
              curwp->w_dotp = lback(curwp->w_dotp);

            curwp->w_doto = 0;
        }
        else{
          /* leave cursor on first word in para */
            curwp->w_doto = 0;
            while(ucs4_isspace(lgetc(curwp->w_dotp, curwp->w_doto).c))
              if(++curwp->w_doto >= llength(curwp->w_dotp)){
                  curwp->w_doto = 0;
                  curwp->w_dotp = lforw(curwp->w_dotp);
                  if(curwp->w_dotp == curbp->b_linep)
                    break;
              }
        }
    }

    curwp->w_flag |= WFMOVE;    /* force screen update */
    return(TRUE);
}


/* 
 * go forword to the end of the current paragraph
 * here we look for a <NL><NL> or <NL><TAB> or <NL><SPACE>
 * combination to delimit the beginning of a paragraph
 */
int
gotoeop(int f, int n)
{
    int quoted, qlen;
    UCS qstr[NLINE], qstr2[NLINE];

    if (n < 0)  /* the other way...*/
      return(gotobop(f, -n));

    while (n-- > 0) {   /* for each one asked for */

        while(lisblank(curwp->w_dotp)){
            curwp->w_doto = 0;
            if((curwp->w_dotp = lforw(curwp->w_dotp)) == curbp->b_linep)
              break;
        }

        /* scan line by line until we come to a line ending with
         * a <NL><NL> or <NL><TAB> or <NL><SPACE>
         *
         * PLUS: if there's a quote string, a quoted-to-non-quoted
         *       line transition.
         */
        quoted = quote_match(glo_quote_str,
                        curwp->w_dotp, qstr, NLINE);
        qlen   = quoted ? ucs4_strlen(qstr) : 0;
        
        while(curwp->w_dotp != curbp->b_linep
              && llength(lforw(curwp->w_dotp)) > qlen
              && (quoted == quote_match(glo_quote_str,
                                           lforw(curwp->w_dotp),
                                           qstr2, NLINE)
                     && !ucs4_strcmp(qstr, qstr2))
              && lgetc(lforw(curwp->w_dotp), qlen).c != TAB
              && lgetc(lforw(curwp->w_dotp), qlen).c != ' ')
          curwp->w_dotp = lforw(curwp->w_dotp);

        curwp->w_doto = llength(curwp->w_dotp);

        /* still looking? */
        if(n){
            if(curwp->w_dotp == curbp->b_linep)
              break;
            else
              curwp->w_dotp = lforw(curwp->w_dotp);

            curwp->w_doto = 0;
        }
    }

    curwp->w_flag |= WFMOVE;    /* force screen update */
    return(curwp->w_dotp != curbp->b_linep);
}

/*
 * This routine, given a pointer to a LINE, and the current cursor goal
 * column, return the best choice for the offset. The offset is returned.
 * Used by "C-N" and "C-P".
 */
int
getgoal(LINE *dlp)
{
    UCS    c;
    register int    col;
    register int    newcol;
    register int    dbo;

    col = 0;
    dbo = 0;
    while (dbo != llength(dlp)) {
        c = lgetc(dlp, dbo).c;
        newcol = col;

        if (c == '\t'){
            newcol |= 0x07;
            ++newcol;
        }
        else if (ISCONTROL(c)){
            newcol += 2;
        }
        else{
            int w;

            w = wcellwidth(c);
            newcol += (w >= 0 ? w : 1);
        }

        if (newcol > curgoal)
          break;

        col = newcol;
        ++dbo;
    }

    return (dbo);
}


/*
 * Scroll the display forward (up) n lines.
 */
int
scrollforw(int n, int movedot)
{
    register LINE   *lp;
    LINE            *lp2;
    register int    nl;
    int             i;

    nl = n;
    lp = curwp->w_linep;
    while (n-- && lp!=curbp->b_linep)
      lp = lforw(lp);

    if (movedot) {                      /* Move dot to top of page. */
        curwp->w_dotp  = lp;
        curwp->w_doto  = 0;
    }

    curwp->w_flag |= WFHARD;
    if(lp == curbp->b_linep)
      return(TRUE);
    else
      curwp->w_linep = lp;

    /*
     * if the header is open, close it ...
     */
    if(Pmaster && Pmaster->headents && ComposerTopLine != COMPOSER_TOP_LINE){
        n -= ComposerTopLine - COMPOSER_TOP_LINE;
        ToggleHeader(0);
    }

    /*
     * scroll down from the top the same number of lines we've moved 
     * forward
     */
    if(TERM_OPTIMIZE)
      scrollup(curwp, -1, nl-n-1);

    if(!movedot){
        /* Requested to not move the dot.  Look for the dot in the current
         * window.  loop through all lines, stop when at end of window
         * or endof buffer.  If the dot is found, it can stay where it
         * is, otherwise we do need to move it.
         */
        movedot = TRUE;
        for (   lp2 = lp, i = 0; 
                lp2 != curbp->b_linep && i < curwp->w_ntrows;  
                lp2 = lforw(lp2), ++i) {
            if (curwp->w_dotp == lp2) {
                 movedot = FALSE;
                 break;
            }
        }
        if (movedot) {
            /* Dot not found in window.  Move to first line of window. */
            curwp->w_dotp  = lp;
            curwp->w_doto  = 0;
        }
    }

    return (TRUE);
}


/*
 * Scroll forward by a specified number of lines, or by a full page if no
 * argument. Bound to "C-V". The "2" in the arithmetic on the window size is
 * the overlap; this value is the default overlap value in ITS EMACS. Because
 * this zaps the top line in the display window, we have to do a hard update.
 */
int
forwpage(int f, int n)
{

    if (f == FALSE) {
        n = curwp->w_ntrows - 2;        /* Default scroll.      */
        if (n <= 0)                     /* Forget the overlap   */
          n = 1;                  /* if tiny window.      */
    } else if (n < 0)
      return (backpage(f, -n));
#if     CVMVAS
    else                                    /* Convert from pages   */
      n *= curwp->w_ntrows;           /* to lines.            */
#endif
    return (scrollforw (n, TRUE));
}


/*
 * Scroll back (down) number of lines.  
 */
int
scrollback(int n, int movedot)
{
    register LINE   *lp, *tp;
    register int    nl;
    int             i;

    if(Pmaster && Pmaster->headents){
        /*
         * go up into editing the mail header if on the top line
         * and the user hits the up arrow!!!
         */
        if (lback(curwp->w_dotp) == curbp->b_linep){
            /*
             * if the editor returns anything except -1 then the user
             * has requested something special, so let pico know...
             */
            return(HeaderEditor(1, 1));
        }
    }

    /*
     * Count back the number of lines requested.
     */
    nl = n;
    lp = curwp->w_linep;
    while (n-- && lback(lp)!=curbp->b_linep)
      lp = lback(lp);

    curwp->w_linep = lp;
    curwp->w_flag |= WFHARD;

    /*
     * scroll down from the top the same number of lines we've moved 
     * forward
     *
     * This isn't too cool, but it has to be this way so we can 
     * gracefully scroll in the message header
     */
    if(Pmaster && Pmaster->headents){
        if((lback(lp)==curbp->b_linep) && (ComposerTopLine==COMPOSER_TOP_LINE))
          n -= entry_line(1000, TRUE); /* never more than 1000 headers */
        if(nl-n-1 < curwp->w_ntrows)
          if(TERM_OPTIMIZE)
            scrolldown(curwp, -1, nl-n-1);
    }
    else
      if(TERM_OPTIMIZE)
        scrolldown(curwp, -1, nl-n-1);

    if(Pmaster && Pmaster->headents){
        /*
         * if we're at the top of the page, and the header is closed, 
         * open it ...
         */
        if((lback(lp) == curbp->b_linep) 
           && (ComposerTopLine == COMPOSER_TOP_LINE)){
            ToggleHeader(1);
            movecursor(ComposerTopLine, 0);
        }
    }
    
    /*
     * Decide if we move the dot or not.  Calculation done AFTER deciding
     * if we display the header because that will change the number of
     * lines on the screen.
     */
    if (movedot) {
        /* Dot gets put at top of window. */
        curwp->w_dotp  = curwp->w_linep;
        curwp->w_doto  = 0;
    }
    else {
        /* Requested not to move dot, but we do need to keep in on
         * the screen.  Verify that it is still in the range of lines
         * visible in the window.  Loop from the first line to the
         * last line, until we reach the end of the buffer or the end
         * of the window.  If we find the dot, then we don't need
         * to move it. */
        movedot = TRUE;
        for (   tp = curwp->w_linep, i = 0; 
                tp != curbp->b_linep && i < curwp->w_ntrows;  
                tp = lforw(tp), ++i) {
            if (curwp->w_dotp == tp) {
                 movedot = FALSE;
                 break;
            }
        }
        if (movedot) {
            /* Dot not found in window.  Move to last line of window. */
            curwp->w_dotp  = lback (tp);
            curwp->w_doto  = 0;
        }
    }

    return (TRUE);
}




/*
 * This command is like "forwpage", but it goes backwards. The "2", like
 * above, is the overlap between the two windows. The value is from the ITS
 * EMACS manual. Bound to "M-V". We do a hard update for exactly the same
 * reason.
 */
int
backpage(int f, int n)
{

    if (f == FALSE) {
        n = curwp->w_ntrows - 2;        /* Default scroll.      */
        if (n <= 0)                     /* Don't blow up if the */
          n = 1;                  /* window is tiny.      */
    } else if (n < 0)
      return (forwpage(f, -n));
#if     CVMVAS
    else                                    /* Convert from pages   */
      n *= curwp->w_ntrows;           /* to lines.            */
#endif
    return (scrollback (n, TRUE));
}


int
scrollupline(int f, int n)
{
    return (scrollback (1, FALSE));
}


int
scrolldownline(int f, int n)
{
    return (scrollforw (1, FALSE));
}



/*
 * Scroll to a position.
 */
int
scrollto(int f, int n)
{
#ifdef _WINDOWS
    long        scrollLine;
    LINE        *lp;
    int         i;
    
    scrollLine = mswin_getscrollto ();
    
    /*
     * Starting at the first data line in the buffer, step forward
     * 'scrollLine' lines to find the new top line.  It is a circular
     * list of buffers, so watch for the first line to reappear.  if
     * it does, we have some sort of internal error, abort scroll
     * operation.  Also watch for NULL, just in case.
     */
    lp = lforw (curbp->b_linep);
    for (i = 0; i < scrollLine && lp != curbp->b_linep && lp != NULL; ++i)
        lp = lforw(lp);

    if (lp == curbp->b_linep || lp == NULL)
        return (FALSE);                                 /* Whoops! */
    

    /* Set the new top line for the window and flag a redraw. */
    curwp->w_linep = lp;
    curwp->w_dotp  = lp;
    curwp->w_doto  = 0;
    curwp->w_flag |= WFHARD;
    
    if(Pmaster && Pmaster->headents){
        /*
         * If we are at the top of the page and header not open, open it.
         * If we are not at the top of the page and the header is open,
         * close it.
         */
        if((lback(lp) == curbp->b_linep) 
           && (ComposerTopLine == COMPOSER_TOP_LINE)){
            ToggleHeader(1);
            movecursor(ComposerTopLine, 0);
        }
        else if((lback(lp) != curbp->b_linep) 
           && (ComposerTopLine != COMPOSER_TOP_LINE)){
           ToggleHeader (0);
        }
    }
#endif

    return (TRUE);
}



/*
 * Set the mark in the current window to the value of "." in the window. No
 * errors are possible. Bound to "M-.".  If told to set an already set mark
 * unset it.
 */
int
setmark(int f, int n)
{
    if(!curwp->w_markp){
        curwp->w_markp = curwp->w_dotp;
        curwp->w_marko = curwp->w_doto;
        if(n)
          emlwrite("Mark Set", NULL);
    }
    else{
        /* clear inverse chars between here and dot */
        markregion(0);
        curwp->w_markp = NULL;
        if(n)
          emlwrite("Mark UNset", NULL);
    }

#ifdef  _WINDOWS
    mswin_allowcopycut(curwp->w_markp ? kremove : NULL);
#endif
    return (TRUE);
}


/*
 * Swap the values of "." and "mark" in the current window. This is pretty
 * easy, because all of the hard work gets done by the standard routine
 * that moves the mark about. The only possible error is "no mark". Bound to
 * "C-X C-X".
 */
int
swapmark(int f, int n)
{
    register LINE   *odotp;
    register int    odoto;

    if (curwp->w_markp == NULL) {
        if(Pmaster == NULL)
          emlwrite("No mark in this window", NULL);
        return (FALSE);
    }

    odotp = curwp->w_dotp;
    odoto = curwp->w_doto;
    curwp->w_dotp  = curwp->w_markp;
    curwp->w_doto  = curwp->w_marko;
    curwp->w_markp = odotp;
    curwp->w_marko = odoto;
    curwp->w_flag |= WFMOVE;
    return (TRUE);
}


/*
 * Set the mark in the current window to the value of "." in the window. No
 * errors are possible. Bound to "M-.".  If told to set an already set mark
 * unset it.
 */
int
setimark(int f, int n)
{
    curwp->w_imarkp = curwp->w_dotp;
    curwp->w_imarko = curwp->w_doto;
    return(TRUE);
}


/*
 * Swap the values of "." and "mark" in the current window. This is pretty
 * easy, because all of the hard work gets done by the standard routine
 * that moves the mark about. The only possible error is "no mark". Bound to
 * "C-X C-X".
 */
int
swapimark(int f, int n)
{
    register LINE   *odotp;
    register int    odoto;

    if (curwp->w_imarkp == NULL) {
        if(Pmaster == NULL)
          emlwrite("Programmer botch! No mark in this window", NULL);
        return (FALSE);
    }

    odotp = curwp->w_dotp;
    odoto = curwp->w_doto;
    curwp->w_dotp  = curwp->w_imarkp;
    curwp->w_doto  = curwp->w_imarko;
    curwp->w_imarkp = odotp;
    curwp->w_imarko = odoto;
    curwp->w_flag |= WFMOVE;
    return (TRUE);
}


/*
 * If dot comes before mark, do nothing.
 * If mark comes before dot, swap them.
 */
void
swap_mark_and_dot_if_mark_comes_first(void)
{
    LINE *blp, *flp;

    if(!(curwp && curwp->w_dotp && curwp->w_markp))
      return;

    if(curwp->w_dotp == curwp->w_markp){        /* they are in the same line */
        if(curwp->w_doto > curwp->w_marko)
          swapmark(0,1);

        return;
    }

    /*
     * Search forward and backward from dot to see if mark
     * is less than or greater than dot.
     */
    flp = blp = curwp->w_dotp;
    while(flp != curbp->b_linep || lback(blp) != curbp->b_linep){
        if(flp != curbp->b_linep){
            flp = lforw(flp);
            if(flp == curwp->w_markp)           /* dot already less than mark */
              return;
        }

        if(lback(blp) != curbp->b_linep){
            blp = lback(blp);
            if(blp == curwp->w_markp){
                swapmark(0, 1);
                return;
            }
        }
    }
}


#ifdef MOUSE

/*
 * Handle a mouse down.
 */
int
mousepress(int f, int n)
{
    MOUSEPRESS  mp;
    LINE        *lp;
    int    i;


    mouse_get_last (NULL, &mp);


    lp = curwp->w_linep;
    i = mp.row - ((Pmaster && Pmaster->headents) ? ComposerTopLine : 2);
    if (i < 0) {
        if (Pmaster) {
            /* Clear existing region. */
            if (curwp->w_markp)
                setmark(0,1);   

            /* Move to top of document before editing header. */
            curwp->w_dotp = curwp->w_linep;
            curwp->w_doto = 0;
            curwp->w_flag |= WFMOVE;
            update ();                          /* And update. */

            return (HeaderEditor (1, 1));
        }
    }
    else {
        while(i-- && lp != curbp->b_linep)
          lp = lforw(lp);

        curgoal = mp.col;
        curwp->w_dotp = lp;
        curwp->w_doto = getgoal(lp);
        curwp->w_flag |= WFMOVE;

        if(mp.doubleclick)
            setmark(0, 1);
    }

    return(FALSE);
}


int
toggle_xterm_mouse(int f, int n)
{
#ifndef _WINDOWS
    int e;

    (e=mouseexist()) ? end_mouse() : (void) init_mouse();
    if(e != mouseexist()){
        mouseexist() ? emlwrite(_("Xterm mouse tracking on!"), NULL)
                     : emlwrite(_("Xterm mouse tracking off!"), NULL);
    }
    else if(!e)
      emlwrite(_("Xterm mouse tracking still off ($DISPLAY variable set?)"), NULL);
#endif
    return(TRUE);
}
#endif