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Revised dohistexpand()
- X-seq: zsh-workers 297
- From: P.Stephenson@xxxxxxxxxxxxx
- To: zsh-workers@xxxxxxxxxxxxxxx (Zsh hackers list)
- Subject: Revised dohistexpand()
- Date: Wed, 09 Aug 95 14:44:36 +0100
Here's another step on the way to rationalising the history code.
It's for hzoli10.2, simply because that's the latest generally
available version: there have been so many patches that I don't dare
to patch the official version at the moment. I'll revise this when
2.6-beta11 comes out.
One of the bits I like least about the history code (and that's a bold
statement) is the zle history expansion. The problem is that it
relies on calling the lexer, and via that the history code, and those
together build up a new editing line directly. This is one more
reason why the history code is hard to maintain, and is also very
wasteful: neither the resulting tokens nor the resulting history line
are used.
This revised version eliminates the lexer and uses hgetc() to get
history expansion directly. As most of the work is now done specially
in doexpandhist(), it was possible to rewrite it so that only history
expansions in the current word are expanded, which is now in keeping
with other forms of expansion and completion. This alone should make
it all worthwhile. For example,
% cmd !!:1 z<TAB>
will now do completion on the second argument, as you would expect;
formerly it would expand the previous history reference first.
There are a couple of drawbacks: single quotes don't hide this form of
expansion (though again that's just like glob expansion: try typing
'*' and then tab), and complex substitutions like !:s/a b/c d/ will
sometimes be mishandled (though usually you get what you deserve,
particularly if you've just finished typing the whole expression). I
don't think either of these is at all significant. I have also made
sure that magic-space still works.
There is still some small collusion with the history code: when
expanding, the history line is not modified and the pair \! is left as
it is instead of being turned into !. These are algorithmically
simple and self-contained, however. It may also be possible to
simplify the qbang logic in hist.c (it's now not needed at all when
expanding), but I don't know enough about that (yet).
*** Src/globals.h.he Mon Jul 24 18:08:29 1995
--- Src/globals.h Tue Aug 8 23:10:45 1995
***************
*** 124,133 ****
EXTERN int expanding;
- /* these are used to modify the cursor position during expansion */
-
- EXTERN int excs, exlast;
-
/* if != 0, this is the first line of the command */
EXTERN int isfirstln;
--- 124,129 ----
*** Src/hist.c.he Wed Jul 19 18:00:26 1995
--- Src/hist.c Wed Aug 9 12:31:40 1995
***************
*** 66,98 ****
}
}
- /* This function adds a character to the zle input line. It is used when *
- * zsh expands history (see doexpandhist() in zle_tricky.c). It also *
- * calculates the new cursor position after the expansion. It is called *
- * from hgetc() and from gettok() in lex.c for characters in comments. */
-
/**/
- void
- addtoline(int c)
- {
- if (qbang && c == bangchar && stophist < 2) {
- exlast--;
- spaceinline(1);
- line[cs++] = '\\';
- }
- if (excs > cs) {
- excs += 1 + inbufct - exlast;
- if (excs < cs)
- /* this case could be handled better but it is *
- * so rare that it does not worth it */
- excs = cs;
- }
- exlast = inbufct;
- spaceinline(1);
- line[cs++] = itok(c) ? ztokens[c - Pound] : c;
- }
-
- /**/
int
hgetc(void)
{
--- 66,72 ----
***************
*** 101,106 ****
--- 75,88 ----
qbang = 0;
if (!stophist && !alstackind) {
/* If necessary, expand history characters. */
+ if (expanding == 2) {
+ /* If only expanding history, leave \! pairs alone.
+ * We marked a \! pair and returned the \, but the ! should
+ * still be treated as quoted.
+ */
+ expanding = 1;
+ return c;
+ }
c = histsubchar(c);
if (c < 0) {
errflag = lexstop = 1;
***************
*** 126,136 ****
* history is disabled with NOBANGHIST or by someone else (e.g. *
* when the lexer scans single quoted text). */
qbang = c == bangchar && (stophist < 2);
! hwaddc(c);
- if (expanding && !lexstop)
- addtoline(c);
-
return c;
}
--- 108,116 ----
* history is disabled with NOBANGHIST or by someone else (e.g. *
* when the lexer scans single quoted text). */
qbang = c == bangchar && (stophist < 2);
! if (!expanding)
! hwaddc(c);
return c;
}
***************
*** 203,208 ****
--- 183,193 ----
if (g != bangchar)
safeinungetc(g);
else {
+ if (expanding == 1) {
+ expanding = 2; /* flag to return literal ! next */
+ inungetc(g);
+ return '\\';
+ }
qbang = 1;
return bangchar;
}
***************
*** 490,500 ****
return;
escape:
- if (expanding) {
- cs--;
- ll--;
- exlast++;
- }
if (hlastw) {
if (hlastw == hptr)
zerr("hungetc attempted at buffer start", NULL, 0);
--- 475,480 ----
*** Src/lex.c.he Tue Aug 1 10:12:24 1995
--- Src/lex.c Tue Aug 8 17:34:02 1995
***************
*** 374,380 ****
if (c == hashchar &&
(isset(INTERACTIVECOMMENTS) ||
! (!zleparse && !expanding && (!interact || unset(SHINSTDIN) || strin)))) {
/* History is handled here to prevent extra newlines
* being inserted into the history.
*
--- 374,380 ----
if (c == hashchar &&
(isset(INTERACTIVECOMMENTS) ||
! (!zleparse && (!interact || unset(SHINSTDIN) || strin)))) {
/* History is handled here to prevent extra newlines
* being inserted into the history.
*
***************
*** 394,406 ****
else {
while (nsp) {
hwaddc(' ');
- if (expanding)
- addtoline(' ');
--nsp;
}
hwaddc(c);
- if (expanding)
- addtoline(c);
}
}
if (errflag)
--- 394,402 ----
***************
*** 409,420 ****
hwadd();
hwbegin();
hwaddc('\n');
- if (expanding) {
- while (nsp--)
- addtoline(' ');
- if (!lexstop)
- addtoline('\n');
- }
peek = NEWLIN;
}
return peek;
--- 405,410 ----
*** Src/zle_tricky.c.he Mon Jul 24 18:14:04 1995
--- Src/zle_tricky.c Wed Aug 9 12:38:48 1995
***************
*** 3691,3758 ****
int
doexpandhist(void)
{
! unsigned char *ol;
! int oll = ll, ocs = cs, ne = noerrs, err;
! heapalloc();
! pushheap();
! ol = (unsigned char *)dupstring((char *)line);
! expanding = 1;
! excs = cs;
! ll = cs = 0;
! lexsave();
! inpush(UTOSCP(ol), 0); /* We push ol as it will remain unchanged */
! strinbeg();
! noaliases = 1;
noerrs = 1;
! exlast = inbufct;
! do {
! ctxtlex();
}
! while (tok != ENDINPUT && tok != LEXERR);
! stophist = 2;
! while (!lexstop)
! hgetc();
! /* We have to save errflags because it's reset in lexrestore. Since
! * noerrs was set to 1 errflag is true if there was a habort() which
! * means that the expanded string is unusable */
! err = errflag;
! noerrs = ne;
! noaliases = 0;
! strinend();
! inpop();
! zleparse = 0;
! lexrestore();
! expanding = 0;
! popheap();
! permalloc();
! if (!err) {
! cs = excs;
! if (strcmp((char *)line, (char *)ol)) {
! /* For vi mode -- reset the beginning-of-insertion pointer to the
! * beginning of the line. This seems a little silly, if we are,
! * for example, expanding "exec !!". */
! if (viinsbegin > findbol())
! viinsbegin = findbol();
! return 1;
}
}
! strcpy((char *)line, (char *)ol);
! ll = oll;
! cs = ocs;
! return 0;
}
/**/
void
magicspace(void)
{
c = ' ';
selfinsert();
- doexpandhist();
}
/**/
--- 3691,3815 ----
int
doexpandhist(void)
{
! int newsz = linesz, newchar, newcount;
! int ls = lexstop, sh = stophist, ifc = isfirstch, ne = noerrs;
! int hd = histdone, ret = 0, test, offs, foundbang;
! char *newline, *newptr, *startptr, *endptr, *spaceptr, sav;
! if (isset(NOBANGHIST))
! return 0;
!
! endptr = startptr = (char *)line + cs;
!
! foundbang = 0;
! while (*endptr && *endptr != ' ') {
! if (*endptr == bangchar)
! foundbang = 1;
! endptr++;
! }
!
! spaceptr = NULL;
! if (!foundbang) {
! /* We still need to go back far enough to find a bang.
! * This is to handle stuff like !!:s/a b/c d/, though you
! * still have to be after the last space for it to work.
! * Spaceptr will point to the first character after the space
! * before the cursor. We require that something between
! * here and endptr has changed to accept the expansion.
! */
! while (startptr > (char *)line && *startptr != bangchar) {
! startptr--;
! if (*startptr == ' ' && !spaceptr)
! spaceptr = startptr;
! }
! if (*startptr != '^' && *startptr != bangchar)
! return 0;
! }
!
! if (startptr == endptr) {
! /* If no characters here, don't try expansion */
! return 0;
! }
!
! /* Either we found a bangchar, or a ^ at the beginning of the line. */
!
! /* Make sure we get complete word. */
! while (startptr > (char *)line && startptr[-1] != ' ')
! startptr--;
! sav = *endptr;
! *endptr = '\0';
!
! newptr = newline = malloc(newsz);
!
! inpush(startptr, 0);
! lexstop = 0;
! strin = 1;
! stophist = 0;
! isfirstch = (startptr == (char *)line);
noerrs = 1;
! expanding = 1;
! /* What about the alias stack? */
!
! for (newcount = 0;; newcount++) {
! if (newcount == newsz) {
! newline = (char *)realloc(newline, (newsz *= 4));
! newptr = newline + newcount;
! }
! newchar = hgetc();
! if (errflag || lexstop)
! break;
!
! *newptr++ = newchar;
}
! *newptr = '\0';
! *endptr = sav;
!
! if (!errflag) {
! /* We've now expanded from startptr to newptr; see if it's
! * changed. If we set spaceptr, we want to make sure the
! * text after that was changed, else the expansion wasn't in
! * the current word and we reject it.
! */
! if (spaceptr && (offs = newcount - (endptr - spaceptr)) > 0) {
! test = strcmp(spaceptr, newline + offs);
! } else
! test = strcmp(startptr, newline);
! if (test) {
! /* The right bit changed: set cursor to end of it, */
! cs = endptr - (char *)line;
! /* delete it, */
! backdel(endptr - startptr);
! /* and insert the new stuff. */
! spaceinline(newcount);
! memcpy(line+cs, newline, newcount);
! cs += newcount;
! ret = 1;
}
}
+ zfree(newline, newsz);
! expanding = 0;
! noerrs = ne;
! isfirstch = ifc;
! stophist = sh;
! strin = 0;
! lexstop = ls;
! histdone = hd;
! inpop();
! errflag = 0;
!
! return ret;
}
/**/
void
magicspace(void)
{
+ doexpandhist();
c = ' ';
selfinsert();
}
/**/
--
Peter Stephenson <P.Stephenson@xxxxxxxxxxxxx> Tel: +44 1792 205678 extn. 4461
WWW: http://python.swan.ac.uk/~pypeters/ Fax: +44 1792 295324
Department of Physics, University of Wales, Swansea,
Singleton Park, Swansea, SA2 8PP, U.K.
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