Minor clean up, better distinguish between sline and sindex.

Fix off-by-one bug in '$.
Document M and ESC-m commands.

command.c

@@ -1789,7 +1789,7 @@ commands()
  /*
  * Clear a mark.
  */
- start_mca(A_SETMARK, "clear mark: ", (void*)NULL, 0);
+ start_mca(A_CLRMARK, "clear mark: ", (void*)NULL, 0);
  c = getcc();
  if (is_erase_char(c) || is_newline_char(c))
  break;
@@ -1801,7 +1801,7 @@ commands()
  /*
  * Jump to a marked position.
  */
- start_mca(A_SETMARK, "goto mark: ", (void*)NULL, 0);
+ start_mca(A_GOMARK, "goto mark: ", (void*)NULL, 0);
  c = getcc();
  if (is_erase_char(c) || is_newline_char(c))
  break;

jump.c

@@ -44,7 +44,7 @@ jump_forw()
  end_pos = ch_tell();
  pos = back_line(end_pos);
  if (pos == NULL_POSITION)
- jump_loc((POSITION)0, sc_height-1);
+ jump_loc(ch_zero(), sc_height-1);
  else
  {
  jump_loc(pos, sc_height-1);
@@ -119,7 +119,7 @@ repaint()
  pos_clear();
  if (scrpos.pos == NULL_POSITION)
  /* Screen hasn't been drawn yet. */
- jump_loc(0, 0);
+ jump_loc(ch_zero(), 1);
  else
  jump_loc(scrpos.pos, scrpos.ln);
 }
@@ -194,21 +194,22 @@ jump_loc(pos, sline)
  int sline;
 {
  int nline;
+ int sindex;
  POSITION tpos;
  POSITION bpos;
 
  /*
  * Normalize sline.
  */
- sline = adjsline(sline);
+ sindex = sindex_from_sline(sline);
 
  if ((nline = onscreen(pos)) >= 0)
  {
  /*
  * The line is currently displayed. 
  * Just scroll there.
  */
- nline -= sline;
+ nline -= sindex;
  if (nline > 0)
  forw(nline, position(BOTTOM_PLUS_ONE), 1, 0, 0);
  else if (nline < 0)
@@ -244,7 +245,7 @@ jump_loc(pos, sline)
  * call forw() and put the desired line at the 
  * sline-th line on the screen.
  */
- for (nline = 0; nline < sline; nline++)
+ for (nline = 0; nline < sindex; nline++)
  {
  if (bpos != NULL_POSITION && pos <= bpos)
  {
@@ -253,7 +254,7 @@ jump_loc(pos, sline)
  * close enough to the current screen
  * that we can just scroll there after all.
  */
- forw(sc_height-sline+nline-1, bpos, 1, 0, 0);
+ forw(sc_height-sindex+nline-1, bpos, 1, 0, 0);
 #if HILITE_SEARCH
  if (show_attn)
  repaint_hilite(1);
@@ -275,16 +276,16 @@ jump_loc(pos, sline)
  lastmark();
  squished = 0;
  screen_trashed = 0;
- forw(sc_height-1, pos, 1, 0, sline-nline);
+ forw(sc_height-1, pos, 1, 0, sindex-nline);
  } else
  {
  /*
  * The desired line is before the current screen.
  * Move forward in the file far enough so that we
  * can call back() and put the desired line at the 
- * sline-th line on the screen.
+ * sindex-th line on the screen.
  */
- for (nline = sline; nline < sc_height - 1; nline++)
+ for (nline = sindex; nline < sc_height - 1; nline++)
  {
  pos = forw_line(pos);
  if (pos == NULL_POSITION)

less.hlp.VER

@@ -69,10 +69,12 @@
  Each "find open bracket" command goes backward to the open bracket 
  matching the (_N-th) close bracket in the bottom line.
 
- m_<_l_e_t_t_e_r_> Mark the current position with <letter>.
+ m_<_l_e_t_t_e_r_> Mark the current top line with <letter>.
+ M_<_l_e_t_t_e_r_> Mark the current bottom line with <letter>.
  '_<_l_e_t_t_e_r_> Go to a previously marked position.
  '' Go to the previous position.
  ^X^X Same as '.
+ ESC-M_<_l_e_t_t_e_r_> Clear a mark.
  ---------------------------------------------------
  A mark is any upper-case or lower-case letter.
  Certain marks are predefined:

less.nro.VER

@@ -181,9 +181,6 @@ the status column shows the marked line.
 .IP M
 Acts like m, except the last displayed line is marked
 rather than the first displayed line.
-.IP "ESC-m"
-Followed by any lowercase or uppercase letter,
-removes the mark identified by that letter.
 .IP "'"
 (Single quote.)
 Followed by any lowercase or uppercase letter, returns to the position which
@@ -196,6 +193,9 @@ Marks are preserved when a new file is examined,
 so the ' command can be used to switch between input files.
 .IP "^X^X"
 Same as single quote.
+.IP "ESC-m"
+Followed by any lowercase or uppercase letter,
+clears the mark identified by that letter.
 .IP /pattern
 Search forward in the file for the N-th line containing the pattern.
 N defaults to 1.

mark.c

@@ -80,7 +80,7 @@ getmark(c)
  }
  m = &sm;
  m->m_scrpos.pos = ch_tell();
- m->m_scrpos.ln = sc_height-1;
+ m->m_scrpos.ln = sc_height;
  m->m_ifile = curr_ifile;
  break;
  case '.':

position.c

@@ -29,21 +29,22 @@ extern int sc_width, sc_height;
  * the line after the bottom line on the screen
  */
  public POSITION
-position(where)
- int where;
+position(sindex)
+ int sindex;
 {
- switch (where)
+ switch (sindex)
  {
  case BOTTOM:
- where = sc_height - 2;
+ sindex = sc_height - 2;
  break;
  case BOTTOM_PLUS_ONE:
- where = sc_height - 1;
+ sindex = sc_height - 1;
  break;
  case MIDDLE:
- where = (sc_height - 1) / 2;
+ sindex = (sc_height - 1) / 2;
+ break;
  }
- return (table[where]);
+ return (table[sindex]);
 }
 
 /*
@@ -213,7 +214,7 @@ get_scrpos(scrpos, where)
  * relative to the bottom of the screen.
  */
  public int
-adjsline(sline)
+sindex_from_sline(sline)
  int sline;
 {
  /*
@@ -223,12 +224,12 @@ adjsline(sline)
  if (sline < 0)
  sline += sc_height;
  /*
- * Can't be less than 1 or greater than sc_height-1.
+ * Can't be less than 1 or greater than sc_height.
  */
  if (sline <= 0)
  sline = 1;
- if (sline >= sc_height)
- sline = sc_height - 1;
+ if (sline > sc_height)
+ sline = sc_height;
  /*
  * Return zero-based line number, not one-based.
  */

prompt.c

@@ -457,7 +457,7 @@ wherechar(p, wp)
  case 'm': *wp = MIDDLE; break;
  case 'b': *wp = BOTTOM; break;
  case 'B': *wp = BOTTOM_PLUS_ONE; break;
- case 'j': *wp = adjsline(jump_sline); break;
+ case 'j': *wp = sindex_from_sline(jump_sline); break;
  default: *wp = TOP; p--; break;
  }
  }

screen.c

@@ -1914,14 +1914,14 @@ check_winch()
  * Goto a specific line on the screen.
  */
  public void
-goto_line(slinenum)
- int slinenum;
+goto_line(sindex)
+ int sindex;
 {
 #if !MSDOS_COMPILER
- tputs(tgoto(sc_move, 0, slinenum), 1, putchr);
+ tputs(tgoto(sc_move, 0, sindex), 1, putchr);
 #else
  flush();
- _settextposition(slinenum+1, 1);
+ _settextposition(sindex+1, 1);
 #endif
 }
 

search.c

@@ -251,7 +251,7 @@ prev_pattern(info)
 repaint_hilite(on)
  int on;
 {
- int slinenum;
+ int sindex;
  POSITION pos;
  int save_hide_hilite;
 
@@ -273,13 +273,13 @@ repaint_hilite(on)
  return;
  }
 
- for (slinenum = TOP; slinenum < TOP + sc_height-1; slinenum++)
+ for (sindex = TOP; sindex < TOP + sc_height-1; sindex++)
  {
- pos = position(slinenum);
+ pos = position(sindex);
  if (pos == NULL_POSITION)
  continue;
  (void) forw_line(pos);
- goto_line(slinenum);
+ goto_line(sindex);
  put_line();
  }
  lower_left();
@@ -292,7 +292,7 @@ repaint_hilite(on)
  public void
 clear_attn()
 {
- int slinenum;
+ int sindex;
  POSITION old_start_attnpos;
  POSITION old_end_attnpos;
  POSITION pos;
@@ -313,17 +313,17 @@ clear_attn()
  if (squished)
  repaint();
 
- for (slinenum = TOP; slinenum < TOP + sc_height-1; slinenum++)
+ for (sindex = TOP; sindex < TOP + sc_height-1; sindex++)
  {
- pos = position(slinenum);
+ pos = position(sindex);
  if (pos == NULL_POSITION)
  continue;
- epos = position(slinenum+1);
+ epos = position(sindex+1);
  if (pos <= old_end_attnpos &&
  (epos == NULL_POSITION || epos > old_start_attnpos))
  {
  (void) forw_line(pos);
- goto_line(slinenum);
+ goto_line(sindex);
  put_line();
  moved = 1;
  }
@@ -1059,7 +1059,7 @@ search_pos(search_type)
  int search_type;
 {
  POSITION pos;
- int linenum;
+ int sindex;
 
  if (empty_screen())
  {
@@ -1082,7 +1082,7 @@ search_pos(search_type)
  pos = ch_length();
  }
  }
- linenum = 0;
+ sindex = 0;
  } else 
  {
  int add_one = 0;
@@ -1093,30 +1093,30 @@ search_pos(search_type)
  * Search does not include current screen.
  */
  if (search_type & SRCH_FORW)
- linenum = sc_height-1; /* BOTTOM_PLUS_ONE */
+ sindex = sc_height-1; /* BOTTOM_PLUS_ONE */
  else
- linenum = 0; /* TOP */
+ sindex = 0; /* TOP */
  } else if (how_search == OPT_ONPLUS && !(search_type & SRCH_AFTER_TARGET))
  {
  /*
  * Search includes all of displayed screen.
  */
  if (search_type & SRCH_FORW)
- linenum = 0; /* TOP */
+ sindex = 0; /* TOP */
  else
- linenum = sc_height-1; /* BOTTOM_PLUS_ONE */
+ sindex = sc_height-1; /* BOTTOM_PLUS_ONE */
  } else 
  {
  /*
  * Search includes the part of current screen beyond the jump target.
  * It starts at the jump target (if searching backwards),
  * or at the jump target plus one (if forwards).
  */
- linenum = adjsline(jump_sline);
+ sindex = sindex_from_sline(jump_sline);
  if (search_type & SRCH_FORW) 
  add_one = 1;
  }
- pos = position(linenum);
+ pos = position(sindex);
  if (add_one)
  pos = forw_raw_line(pos, (char **)NULL, (int *)NULL);
  }
@@ -1128,17 +1128,17 @@ search_pos(search_type)
  {
  while (pos == NULL_POSITION)
  {
- if (++linenum >= sc_height)
+ if (++sindex >= sc_height)
  break;
- pos = position(linenum);
+ pos = position(sindex);
  }
  } else 
  {
  while (pos == NULL_POSITION)
  {
- if (--linenum < 0)
+ if (--sindex < 0)
  break;
- pos = position(linenum);
+ pos = position(sindex);
  }
  }
  return (pos);