+ /* return the Nth item from a list */
+
+ case EITEM_LISTEXTRACT:
+ {
+ int i;
+ int field_number = 1;
+ uschar *save_lookup_value = lookup_value;
+ uschar *sub[2];
+ int save_expand_nmax =
+ save_expand_strings(save_expand_nstring, save_expand_nlength);
+
+ /* Read the field & list arguments */
+
+ for (i = 0; i < 2; i++)
+ {
+ while (isspace(*s)) s++;
+ if (*s != '{') /*}*/
+ goto EXPAND_FAILED_CURLY;
+
+ sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
+ if (!sub[i]) goto EXPAND_FAILED; /*{*/
+ if (*s++ != '}') goto EXPAND_FAILED_CURLY;
+
+ /* After removal of leading and trailing white space, the first
+ argument must be numeric and nonempty. */
+
+ if (i == 0)
+ {
+ int len;
+ int x = 0;
+ uschar *p = sub[0];
+
+ while (isspace(*p)) p++;
+ sub[0] = p;
+
+ len = Ustrlen(p);
+ while (len > 0 && isspace(p[len-1])) len--;
+ p[len] = 0;
+
+ if (!*p && !skipping)
+ {
+ expand_string_message = US"first argument of \"listextract\" must "
+ "not be empty";
+ goto EXPAND_FAILED;
+ }
+
+ if (*p == '-')
+ {
+ field_number = -1;
+ p++;
+ }
+ while (*p && isdigit(*p)) x = x * 10 + *p++ - '0';
+ if (*p)
+ {
+ expand_string_message = US"first argument of \"listextract\" must "
+ "be numeric";
+ goto EXPAND_FAILED;
+ }
+ field_number *= x;
+ }
+ }
+
+ /* Extract the numbered element into $value. If
+ skipping, just pretend the extraction failed. */
+
+ lookup_value = skipping? NULL : expand_getlistele(field_number, sub[1]);
+
+ /* If no string follows, $value gets substituted; otherwise there can
+ be yes/no strings, as for lookup or if. */
+
+ switch(process_yesno(
+ skipping, /* were previously skipping */
+ lookup_value != NULL, /* success/failure indicator */
+ save_lookup_value, /* value to reset for string2 */
+ &s, /* input pointer */
+ &yield, /* output pointer */
+ &size, /* output size */
+ &ptr, /* output current point */
+ US"extract", /* condition type */
+ &resetok))
+ {
+ case 1: goto EXPAND_FAILED; /* when all is well, the */
+ case 2: goto EXPAND_FAILED_CURLY; /* returned value is 0 */
+ }
+
+ /* All done - restore numerical variables. */
+
+ restore_expand_strings(save_expand_nmax, save_expand_nstring,
+ save_expand_nlength);
+
+ continue;
+ }