Add the `isa` operator

Adds a new infix operator named `isa`, with the semantics that

  $x isa SomeClass

is true if and only if `$x` is a blessed object reference that is either
`SomeClass` directly, or includes the class somewhere in its @ISA
hierarchy. It is false without warning or error for non-references or
non-blessed references.

This operator respects `->isa` method overloading, and is intended to
replace boilerplate code such as

  use Scalar::Util 'blessed';

  blessed($x) and $x->isa("SomeClass")

1 files changed, 2 insertions, 1 deletions

diff --git a/opnames.h b/opnames.h
index d87ba88f01..d63371afd1 100644
--- a/opnames.h
+++ b/opnames.h
@@ -411,10 +411,11 @@ typedef enum opcode {
 	OP_LVREFSLICE	 = 394,
 	OP_LVAVREF	 = 395,
 	OP_ANONCONST	 = 396,
+	OP_ISA		 = 397,
 	OP_max		
 } opcode;
 
-#define MAXO 397
+#define MAXO 398
 #define OP_FREED MAXO
 
 /* the OP_IS_* macros are optimized to a simple range check because