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vi: remember cursor column during vertical motion

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When the 'j'/'k' commands or up/down arrow keys are used to move
the cursor vertically 'vi' remembers the original cursor column
and positions the cursor there if possible.  Also, if the '$'
command has been used to position the cursor at the end of a line
vertical movements keep the cursor at the end of the line.

Make BusyBox 'vi' do the same.

function                                             old     new   delta
refresh                                              674     694     +20
do_cmd                                              4853    4861      +8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 28/0)               Total: 28 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2021-03-28 13:20:01 +01:00 committed by Denys Vlasenko
parent 18871c3f2b
commit 50a2db7dff
1 changed files with 18 additions and 3 deletions
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21
editors/vi.c
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@ -263,6 +263,8 @@ enum {
S_OVER_WS = 3, // used in skip_thing() for moving "dot"
S_END_PUNCT = 4, // used in skip_thing() for moving "dot"
S_END_ALNUM = 5, // used in skip_thing() for moving "dot"
C_END = -1, // cursor is at end of line due to '$' command
};
@ -354,6 +356,8 @@ struct globals {
sigjmp_buf restart; // int_handler() jumps to location remembered here
#endif
struct termios term_orig; // remember what the cooked mode was
int cindex; // saved character index for up/down motion
smallint keep_index; // retain saved character index
#if ENABLE_FEATURE_VI_COLON
char *initial_cmds[3]; // currently 2 entries, NULL terminated
#endif
@ -462,6 +466,8 @@ struct globals {
#define context_end (G.context_end )
#define restart (G.restart )
#define term_orig (G.term_orig )
#define cindex (G.cindex )
#define keep_index (G.keep_index )
#define initial_cmds (G.initial_cmds )
#define readbuffer (G.readbuffer )
#define scr_out_buf (G.scr_out_buf )
@ -992,6 +998,9 @@ static void refresh(int full_screen)
place_cursor(crow, ccol);
if (!keep_index)
cindex = ccol + offset;
old_offset = offset;
#undef old_offset
}
@ -3096,6 +3105,7 @@ static void do_cmd(int c)
// cnt = yf = 0; // quiet the compiler
// p = q = save_dot = buf; // quiet the compiler
memset(buf, '\0', sizeof(buf));
keep_index = FALSE;
show_status_line();
@ -3220,9 +3230,10 @@ static void do_cmd(int c)
case KEYCODE_DOWN: // cursor key Down
do {
dot_next(); // go to next B-o-l
// try stay in same col
dot = move_to_col(dot, ccol + offset);
} while (--cmdcnt > 0);
// try to stay in saved column
dot = cindex == C_END ? end_line(dot) : move_to_col(dot, cindex);
keep_index = TRUE;
break;
case 12: // ctrl-L force redraw whole screen
case 18: // ctrl-R force redraw
@ -3348,6 +3359,8 @@ static void do_cmd(int c)
break;
dot_next();
}
cindex = C_END;
keep_index = TRUE;
break;
case '%': // %- find matching char of pair () [] {}
for (q = dot; q < end && *q != '\n'; q++) {
@ -3827,8 +3840,10 @@ static void do_cmd(int c)
case KEYCODE_UP: // cursor key Up
do {
dot_prev();
dot = move_to_col(dot, ccol + offset); // try stay in same col
} while (--cmdcnt > 0);
// try to stay in saved column
dot = cindex == C_END ? end_line(dot) : move_to_col(dot, cindex);
keep_index = TRUE;
break;
case 'r': // r- replace the current char with user input
c1 = get_one_char(); // get the replacement char