On Mon, Nov 23, 2015 at 01:31:11AM -0700, Anthony J. Bentley wrote:
> When I hit backspace after a backslash, usually I just want to delete
> the backslash. I don't think I've ever intended to input a literal ^?.
> If I ever did want to insert ^H, ^?, or ^U, I would just type ^V first.
>
> I've passed this diff around privately before and gotten a tepid
> response, but it was pointed out to me that it would fit better on tech@.
Original vi had this behaviour. AFAIK no modern vi (esp. all the vim
clones) behaves like this. I never depended on this feature and so think
we can follow the others and drop this magic.
> Index: vi/v_txt.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/vi/vi/v_txt.c,v
> retrieving revision 1.27
> diff -u -p -u -p -r1.27 v_txt.c
> --- vi/v_txt.c 12 Nov 2014 04:28:41 -0000 1.27
> +++ vi/v_txt.c 19 Nov 2014 01:17:45 -0000
> @@ -618,30 +617,21 @@ replay: if (LF_ISSET(TXT_REPLAY))
>
> /*
> * !!!
> - * If this character was quoted by a K_VLNEXT or a backslash, replace
> - * the placeholder (a carat or a backslash) with the new character.
> - * If it was quoted by a K_VLNEXT, we've already adjusted the cursor
> - * because it has to appear on top of the placeholder character. If
> - * it was quoted by a backslash, adjust the cursor now, the cursor
> - * doesn't appear on top of it. Historic practice in both cases.
> + * If this character was quoted by a K_VLNEXT, replace the placeholder
> + * (a carat) with the new character. We've already adjusted the cursor
> + * because it has to appear on top of the placeholder character.
> + * Historic practice.
> *
> * Skip tests for abbreviations; ":ab xa XA" followed by "ixa^V<space>"
> * doesn't perform an abbreviation. Special case, ^V^J (not ^V^M) is
> * the same as ^J, historically.
> */
> - if (quote == Q_BTHIS || quote == Q_VTHIS) {
> + if (quote == Q_VTHIS) {
> FL_CLR(ec_flags, EC_QUOTED);
> if (LF_ISSET(TXT_MAPINPUT))
> FL_SET(ec_flags, EC_MAPINPUT);
>
> - if (quote == Q_BTHIS &&
> - (evp->e_value == K_VERASE || evp->e_value == K_VKILL)) {
> - quote = Q_NOTSET;
> - --tp->cno;
> - ++tp->owrite;
> - goto insl_ch;
> - }
> - if (quote == Q_VTHIS && evp->e_value != K_NL) {
> + if (evp->e_value != K_NL) {
> quote = Q_NOTSET;
> goto insl_ch;
> }
> @@ -1201,31 +1191,6 @@ leftmargin: tp->lb[tp->cno - 1] = ' ';
> if (LF_ISSET(TXT_SHOWMATCH))
> showmatch = 1;
> goto ins_ch;
> - case K_BACKSLASH: /* Quote next erase/kill. */
> - /*
> - * !!!
> - * Historic vi tried to make abbreviations after a backslash
> - * escape work. If you did ":ab x y", and inserted "x\^H",
> - * (assuming the erase character was ^H) you got "x^H", and
> - * no abbreviation was done. If you inserted "x\z", however,
> - * it tried to back up and do the abbreviation, i.e. replace
> - * 'x' with 'y'. The problem was it got it wrong, and you
> - * ended up with "zy\".
> - *
> - * This is really hard to do (you have to remember the
> - * word/non-word state, for example), and doesn't make any
> - * sense to me. Both backslash and the characters it
> - * (usually) escapes will individually trigger the
> - * abbreviation, so I don't see why the combination of them
> - * wouldn't. I don't expect to get caught on this one,
> - * particularly since it never worked right, but I've been
> - * wrong before.
> - *
> - * Do the tests for abbreviations, so ":ab xa XA",
> - * "ixa\<K_VERASE>" performs the abbreviation.
> - */
> - quote = Q_BNEXT;
> - goto insq_ch;
> case K_VLNEXT: /* Quote next character. */
> evp->e_c = '^';
> quote = Q_VNEXT;
> @@ -1363,8 +1328,6 @@ ebuf_chk: if (tp->cno >= tp->len) {
>
> /* Step the quote state forward. */
> if (quote != Q_NOTSET) {
> - if (quote == Q_BNEXT)
> - quote = Q_BTHIS;
> if (quote == Q_VNEXT)
> quote = Q_VTHIS;
> }
> Index: vi/vi.h
> ===================================================================
> RCS file: /cvs/src/usr.bin/vi/vi/vi.h,v
> retrieving revision 1.7
> diff -u -p -u -p -r1.7 vi.h
> --- vi/vi.h 28 Nov 2013 22:12:40 -0000 1.7
> +++ vi/vi.h 19 Nov 2014 01:17:45 -0000
> @@ -218,7 +218,7 @@ typedef struct _smap {
> typedef enum { CNOTSET, FSEARCH, fSEARCH, TSEARCH, tSEARCH } cdir_t;
>
> typedef enum { AB_NOTSET, AB_NOTWORD, AB_INWORD } abb_t;
> -typedef enum { Q_NOTSET, Q_BNEXT, Q_BTHIS, Q_VNEXT, Q_VTHIS } quote_t;
> +typedef enum { Q_NOTSET, Q_VNEXT, Q_VTHIS } quote_t;
>
> /* Vi private, per-screen memory. */
> typedef struct _vi_private {
>
--
:wq Claudio
