index/value array slice operation

kvaslice operator that imlements %a[0,2,4] syntax which
result in list of index/value pairs. Implemented in
consistency with "key/value hash slice" operator.

1 files changed, 44 insertions, 0 deletions

diff --git a/pp.c b/pp.c
index 470ebd1681..2dd0fe8d9a 100644
--- a/pp.c
+++ b/pp.c
@@ -4350,6 +4350,50 @@ PP(pp_aslice)
     RETURN;
 }
 
+PP(pp_kvaslice)
+{
+    dVAR; dSP; dMARK;
+    AV *const av = MUTABLE_AV(POPs);
+    I32 lval = (PL_op->op_flags & OPf_MOD);
+    I32 items = SP - MARK;
+
+    if (PL_op->op_private & OPpMAYBE_LVSUB) {
+       const I32 flags = is_lvalue_sub();
+       if (flags) {
+           if (!(flags & OPpENTERSUB_INARGS))
+	       Perl_croak(aTHX_ "Can't modify index/value array slice in list assignment");
+	   lval = flags;
+       }
+    }
+
+    MEXTEND(SP,items);
+    while (items > 1) {
+	*(MARK+items*2-1) = *(MARK+items);
+	items--;
+    }
+    items = SP-MARK;
+    SP += items;
+
+    while (++MARK <= SP) {
+        SV **svp;
+
+	svp = av_fetch(av, SvIV(*MARK), lval);
+        if (lval) {
+            if (!svp || !*svp || *svp == &PL_sv_undef) {
+                DIE(aTHX_ PL_no_aelem, SvIV(*MARK));
+            }
+	    *MARK = sv_mortalcopy(*MARK);
+        }
+	*++MARK = svp ? *svp : &PL_sv_undef;
+    }
+    if (GIMME != G_ARRAY) {
+	MARK = SP - items*2;
+	*++MARK = items > 0 ? *SP : &PL_sv_undef;
+	SP = MARK;
+    }
+    RETURN;
+}
+
 /* Smart dereferencing for keys, values and each */
 PP(pp_rkeys)
 {