Implement a fill-with menu item

This new option fills the entire marked region with copies of the current cell.
  Implements #35.

src/common/cell.c

@@ -150,6 +150,7 @@ void freecellcontents(Cell *faded)
 void copycell(Cell *to, const Cell *fromcell)
 {
   assert(to != NULLCELL);
+  if (to == fromcell) return;
 
   freecellcontents(to);
   if (fromcell != NULLCELL) {

src/common/main.c

@@ -1201,6 +1201,19 @@ static int do_fill(Sheet *sheet)
 }
 /*}}}*/
 
+/* fill the entire marked region using the current cell */
+void fillwith(Sheet *she)
+{
+  do_mark(she, GET_MARK_ALL);
+  Cell *src = curcell(she);
+  Location dest;
+  bool scan_labels = (src != NULLCELL && getlabel(src) != (const char*)0);
+  /* the following is safe since we have handled copying a cell to itself */
+  for (ALL_LOCS_IN_REGION(she, dest)) copycelltosheet(src, she, dest);
+  if (scan_labels) cachelabels(she);
+  forceupdate(she);
+}
+
 /* do_sort        -- sort block */ /*{{{*/
 static int do_sort(Sheet *sheet)
 {
@@ -1515,6 +1528,7 @@ int do_sheetcmd(Sheet *cursheet, Key c, int moveonly)
     case BLOCK_MOVE: do_move(cursheet,0,0); redraw_sheet(cursheet); break;
     case BLOCK_COPY: do_move(cursheet,1,0); redraw_sheet(cursheet); break;
     case BLOCK_FILL: do_fill(cursheet); redraw_sheet(cursheet); break;
+    case FILL_BLOCK: fillwith(cursheet); redraw_sheet(cursheet); break;
     case BLOCK_SORT: do_sort(cursheet); redraw_sheet(cursheet); break;
     case BLOCK_MIRROR: do_mirror(cursheet); redraw_sheet(cursheet); break;
     case ADJUST_LEFT:

src/common/main.h

@@ -80,7 +80,8 @@ typedef enum {
   K_ABOUT = -54,
   K_HELP = -55,
   K_DUMPCELL = -56,
-  ADJUST_UNDERLINE = -57
+  ADJUST_UNDERLINE = -57,
+  FILL_BLOCK = -58
 } Key;
 
 extern int do_sheetcmd(Sheet *cursheet, Key c, int moveonly);
@@ -89,7 +90,8 @@ extern void moveto(Sheet *sheet, int x, int y, int z);
 extern void movetoloc(Sheet *sheet, const Location dest);
 extern void relmoveto(Sheet *sheet, int x, int y, int z);
 extern void do_mark(Sheet *cursheet, MarkState ms);
-  
+void fillwith(Sheet *she);
+
 #ifdef __cplusplus
 }
 #endif

src/common/sheet.c

@@ -46,18 +46,20 @@ int max_eval;
 /*}}}*/
 
 /* copycelltosheet      -- copy a cell into a sheet*/ /*{{{*/
-static void copycelltosheet(const Cell *fromcell,
-			    Sheet *sheet2, const Location to)
+void copycelltosheet(const Cell *fromcell, Sheet *sheet2, const Location to)
 {
   assert(sheet2 != (Sheet*)0);
+  Cell *tocell = safe_cell_at(sheet2, to);
+  if (fromcell == tocell) return;
 
   freecellofsheet(sheet2, to);
   if (fromcell != NULLCELL)
   /* copy first cell to second */ /*{{{*/
   {
     sheet2->changed = 1;
-    Cell *tocell = initcellofsheet(sheet2, to);
-    copycell(tocell, fromcell);
+    Cell *alsotocell = initcellofsheet(sheet2, to);
+    assert(tocell == NULLCELL || tocell == alsotocell);
+    copycell(alsotocell, fromcell);
   }
   /*}}}*/
 }

src/common/sheet.h

@@ -73,6 +73,7 @@ extern int max_eval;
 void initialize_sheet(Sheet *sheet);
 void resize(Sheet *sheet, int x, int y, int z);
 Cell *initcellofsheet(Sheet *sheet, const Location at);
+void copycelltosheet(const Cell *fromcell, Sheet *sheet2, const Location to);
 Cell *safe_cell_at(Sheet *sheet, const Location at);
 Cell *curcell(Sheet *sheet);
 void cachelabels(Sheet *sheet);

src/fteapot.fl

@@ -428,6 +428,11 @@ table->redraw();} open
 			user_data BLOCK_FILL
 			xywh {0 0 36 21} shortcut 0x90066
 		  }
+		  MenuItem {} {
+			label {FillWith}
+			user_data FILL_BLOCK
+			xywh {0 0 36 30}
+		  }
 		  MenuItem {} {
 			label {C&lear}
 			user_data BLOCK_CLEAR