emacs - How to move to the last point position before popping mark-ring? -

i come below scenario:

assumptions: have 5 marks in total: current mark @ position 5, , 4 marks on mark-ring @ positions: 4,3,2,1 respectively. point location somewhere far away, say, 100.

situation: found error @ 4, c-u c-spc<\kbd> jump position 4 , fixed it. forget save previous point position 100. how jump back?

i understand 1 practice save point position before jump. similar jumps happens , in times problem happens 1 or 2 times. once happens, nice if there remedy it, since seems special position too, (last point position before popping mark-ring).

without remedy, seems painful trip manually go position 4 100 manually, happens in low frequency.

the following code adds current position of point mark-ring when invoke c-u c-spc , lets cycle through previous items in mark ring using c-spc (instead of c-u c-spc):

(setq set-mark-command-repeat-pop t)  (defadvice set-mark-command (before record-current-position (arg) activate)   (when arg (push-mark))) 

explanation

the advice defined above tells emacs call push-mark function before executing body of set-mark-command command (but if set-mark-command called prefix arg).

push-mark adds current position of mark mark ring , sets mark current position of point.

by setting set-mark-command-repeat-pop non-nil value telling emacs keep popping mark when hitting c-spc right after hitting c-u c-spc.

visual example

based on example gave including visualization of full "round trip" below, where:

• x : head of mark ring
• ^ : location of mark
• | : location of point

_{i'm including example completeness. if don't care going on point, mark, , positions in mark ring behind scenes, can stop reading :)}

---

1. situation before hitting c-u c-spc:

   1 2 3 4 5 ... 100       x ^      | 

2. situation after hitting c-u c-spc.

   • after emacs has evaluated body of advice defined above:

     1 2 3 4 5 ... 100         x      ^                | 

     as can see, previous location of mark (5) has been pushed onto mark ring, , mark @ current location of point (100).

   • after emacs has evaluated body of advised command (set-mark-command):

     1 2 3 4 5 ... 100       x ^      | 

     the mark has been popped; since @ 100 before, point remains @ location. mark @ 5 again.

3. situation after hitting c-spc first time:

   1 2 3 4 5 ... 100     x ^ | 

4. locations of a, ^, , | on subsequent invocations of c-spc:

   1 2 3 4 5 ... 100   x ^ |  1 2 3 4 5 ... 100 x ^ |  1 2 3 4 5 ... 100 ^ |            x  1 2 3 4 5 ... 100 |       x      ^  1 2 3 4 5 ... 100       x ^      |