print $var by clicking identifiers in the source window

[MaskRay]

If will be very convenient to execute print $identifier_under_cursor whenever an identifier (the icing on the cake is to recognize x->y or x.y member access operators) is clicked in the source window.

Enabling mouse clicks in ncurses can be achieved with the following snippet. There is also a standalone example at https://bbs.archlinux.org/viewtopic.php?id=199959 .

diff --git c/lib/util/sys_win.cpp i/lib/util/sys_win.cpp
index 0034d80..1c6a1da 100644
--- c/lib/util/sys_win.cpp
+++ i/lib/util/sys_win.cpp
@@ -53,13 +53,17 @@ bool swin_start()
 {
     bool success = swin_set_escdelay();
     if (success) {
-        success = swin_initscr() != NULL;
+        SWINDOW *win = swin_initscr();
+        success = win != NULL;
         if (success) {
             if (swin_has_colors()) {
                 swin_start_color();
                 swin_use_default_colors();
             }
 
+            swin_keypad(win, 1);
+            mousemask(ALL_MOUSE_EVENTS | REPORT_MOUSE_POSITION, NULL);
+
             swin_refresh();
         }

See what escape sequences are generated for mouse tracking:

echo -e "\e[?1000h\e[?1001h\e[?1002h"; cat
# See also https://stackoverflow.com/questions/5966903/how-to-get-mousemove-and-mouseclick-in-bash
# Mouse moving report can be used to display arbitrary selected expression

To obtain the cursor position is tricky, because cgdb employs io.cpp:io_getchar which uses read() on terminals instead of ncurses' getch(). The terminal escape sequences are kind of tricky to parse, especially there are at least 4 different terminal modes for mouse support: 1000 (legacy), 1005, 1006 (the best), 1015 (urxvt) http://invisible-island.net/xterm/ctlseqs/ctlseqs.html . ncurses has its ncurses/base/lib_mouse.c (which supports 1000, 1005, 1006 I think) to translate the escape sequence to a terminal position.

Another improvement is to have a cgdb command to communicate with an external script. The filename and the line number are given to the external script and it should send some gdb commands back which print relevant expressions. Say the cursor is at core->a = core->b + core->c;, i would like the external script to send p core->a; core->b; p core->c back. The external script does not need to be full-fledged parser and it certainly cannot be. But with some regex matching, it could be very useful to give context in many cases.

[XVilka]

Kind of related then too https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

[brasko]

This is a pretty neat idea, I must admit. I'm not sure I personally have the time to work on
this at the moment. However, if you are interested, I could work out some ideas that we
find in common and could aid you along in adding this support.

[MaskRay]

LGTM! I'll delve into the source code for some days to understand how it works first...