PATCH suggestion and completion testing

[Sven Wischnowsky <wischnow@xxxxxxxxxxxxxxxxxxxxxxx>]

The more I play with new completion functions the more I'm of the
opinion that maybe we should do the tests only with shell code. And
now that I found the scalar-reverse subscripting again, this doesn't
look too complicated any more (if we add a small new feature, see below):

Only the slightly more complicated ones:

  -string <num> <str>

    local index=$PREFIX[(in:<num>:)<str>]

    if (( index )); then
      IPREFIX="$IPREFIX$PREFIX[1,index]"
      PREFIX="$PREFIX[index+1,-1]"

    And, yes, this also works for negative <num>s (and for the most
    common case with <num> == -1 this can be simplified, of course).

  -class <num> <class>

   Almost the same as `-string', but with `PREFIX[(in:<num>:)[<class>]]'.

  -after <str>

    local index=${words[1,CURRENT][(I)<str>]}

    if (( index )); then
      words=("${(@)words[index+1,-1]}")

For `-between' this gets a bit more complicated (and the double
subscript may be irritating for some users). But we could make things
easier if we add a new subscript flag that gives the index for `r',
`R', `i', and `I' at which to start. This is easy to implement (see
the patch below) and might be useful anyway.

[Peter: I'd really like to have this (independent from the discussion
about the testing stuff), can we add it?.]

With this:

  -after <str>

    local index=$words[(Ib:CURRENT:)<str>]

    if (( index )); then
      words=("${(@)words[index+1,-1]}")

    And `-mafter' is the same, obviously.

  -between <s1> <s2>

    local i1 i2

    i1=$words[(Ib:CURRENT:)<s1>]
    i2=$words[(ib:i1:)<s2>]

    if (( i1 && i1 < CURRENT && i2 > CURRENT )); then
      words=("${(@)words[i1+1,i2-1]}")

    Again, `-mbetween' would be the same.

We could even put the assignments into the (( ... )), speeding up
things some more.

So. With this, would the tests be simple enough for our users? If we
document them in the manual?

With `compstate[restore]' we could even supply a function `comptest'...

Bye
 Sven

diff -u od/Zsh/params.yo Doc/Zsh/params.yo
--- od/Zsh/params.yo	Sun Feb 28 21:31:51 1999
+++ Doc/Zsh/params.yo	Sun Feb 28 21:39:42 1999
@@ -155,6 +155,11 @@
 the var(n)th or var(n)th last match (if var(expr) evaluates to
 var(n)).  This flag is ignored when the array is associative.
 )
+item(tt(b:)var(expr)tt(:))(
+if combined with `tt(r)', `tt(R)', `tt(i)' or `tt(I)', makes them begin
+at the var(n)th or var(n)th last element, word, or character (if var(expr)
+evaluates to var(n)).  This flag is ignored when the array is associative.
+)
 enditem()
 texinode(Positional Parameters)(Local Parameters)(Array Parameters)(Parameters)
 sect(Positional Parameters)
--- os/params.c	Sun Feb 28 20:45:05 1999
+++ Src/params.c	Sun Feb 28 22:12:40 1999
@@ -680,6 +680,7 @@
 getarg(char **str, int *inv, Value v, int a2, long *w)
 {
     int num = 1, word = 0, rev = 0, ind = 0, down = 0, l, i, ishash;
+    int beg = 0, hasbeg = 0;
     char *s = *str, *sep = NULL, *t, sav, *d, **ta, **p, *tt;
     long r = 0;
     Comp c;
@@ -731,6 +732,18 @@
 		*t = sav;
 		s = t;
 		break;
+	    case 'b':
+		hasbeg = 1;
+		t = get_strarg(++s);
+		if (!*t)
+		    goto flagerr;
+		sav = *t;
+		*t = '\0';
+		if ((beg = mathevalarg(s + 1, &d)) > 0)
+		    beg--;
+		*t = sav;
+		s = t;
+		break;
 	    case 'p':
 		escapes = 1;
 		break;
@@ -869,6 +883,8 @@
 	tokenize(s);
 
 	if ((c = parsereg(s))) {
+	    int len;
+
 	    if (v->isarr) {
 		if (ishash) {
 		    scancomp = c;
@@ -887,28 +903,43 @@
 		    ta = getarrvalue(v);
 		if (!ta || !*ta)
 		    return 0;
-		if (down)
-		    for (r = -1, p = ta + arrlen(ta) - 1; p >= ta; r--, p--) {
-			if (domatch(*p, c, 0) && !--num)
-			    return r;
-		} else
-		    for (r = 1, p = ta; *p; r++, p++)
-			if (domatch(*p, c, 0) && !--num)
-			    return r;
+		len = arrlen(ta);
+		if (beg < 0)
+		    beg += len;
+		if (beg >= 0 && beg < len) {
+		    if (down) {
+			if (!hasbeg)
+			    beg = len - 1;
+			for (r = 1 + beg, p = ta + beg; p >= ta; r--, p--) {
+			    if (domatch(*p, c, 0) && !--num)
+				return r;
+			}
+		    } else
+			for (r = 1 + beg, p = ta + beg; *p; r++, p++)
+			    if (domatch(*p, c, 0) && !--num)
+				return r;
+		}
 	    } else if (word) {
 		ta = sepsplit(d = s = getstrvalue(v), sep, 1);
-		if (down) {
-		    for (p = ta + (r = arrlen(ta)) - 1; p >= ta; p--, r--)
-			if (domatch(*p, c, 0) && !--num)
-			    break;
-		    if (p < ta)
-			return 0;
-		} else {
-		    for (r = 1, p = ta; *p; r++, p++)
-			if (domatch(*p, c, 0) && !--num)
-			    break;
-		    if (!*p)
-			return 0;
+		len = arrlen(ta);
+		if (beg < 0)
+		    beg += len;
+		if (beg >= 0 && beg < len) {
+		    if (down) {
+			if (!hasbeg)
+			    beg = len - 1;
+			for (r = 1 + beg, p = ta + beg; p >= ta; p--, r--)
+			    if (domatch(*p, c, 0) && !--num)
+				break;
+			if (p < ta)
+			    return 0;
+		    } else {
+			for (r = 1 + beg, p = ta + beg; *p; r++, p++)
+			    if (domatch(*p, c, 0) && !--num)
+				break;
+			if (!*p)
+			    return 0;
+		    }
 		}
 		if (a2)
 		    r++;
@@ -924,35 +955,46 @@
 		d = getstrvalue(v);
 		if (!d || !*d)
 		    return 0;
-		if (a2) {
-		    if (down)
-			for (r = -2, t = d + strlen(d) - 1; t >= d; r--, t--) {
-			    sav = *t;
-			    *t = '\0';
-			    if (domatch(d, c, 0) && !--num) {
+		len = strlen(d);
+		if (beg < 0)
+		    beg += len;
+		if (beg >= 0 && beg < len) {
+		    if (a2) {
+			if (down) {
+			    if (!hasbeg)
+				beg = len - 1;
+			    for (r = beg, t = d + beg; t >= d; r--, t--) {
+				sav = *t;
+				*t = '\0';
+				if (domatch(d, c, 0) && !--num) {
+				    *t = sav;
+				    return r;
+				}
 				*t = sav;
-				return r;
 			    }
-			    *t = sav;
-		    } else
-			for (r = 0, t = d; *t; r++, t++) {
-			    sav = *t;
-			    *t = '\0';
-			    if (domatch(d, c, 0) && !--num) {
+			} else
+			    for (r = beg, t = d + beg; *t; r++, t++) {
+				sav = *t;
+				*t = '\0';
+				if (domatch(d, c, 0) && !--num) {
+				    *t = sav;
+				    return r;
+				}
 				*t = sav;
-				return r;
 			    }
-			    *t = sav;
-			}
-		} else {
-		    if (down)
-			for (r = -1, t = d + strlen(d) - 1; t >= d; r--, t--) {
-			    if (domatch(t, c, 0) && !--num)
-				return r;
-		    } else
-			for (r = 1, t = d; *t; r++, t++)
-			    if (domatch(t, c, 0) && !--num)
-				return r;
+		    } else {
+			if (down) {
+			    if (!hasbeg)
+				beg = len - 1;
+			    for (r = beg + 1, t = d + beg; t >= d; r--, t--) {
+				if (domatch(t, c, 0) && !--num)
+				    return r;
+			    }
+			} else
+			    for (r = beg + 1, t = d + beg; *t; r++, t++)
+				if (domatch(t, c, 0) && !--num)
+				    return r;
+		    }
 		}
 		return 0;
 	    }

--
Sven Wischnowsky                         wischnow@xxxxxxxxxxxxxxxxxxxxxxx