add support an test for nqp::invokable()

Author: cognominal

src/QAST/Operations.nqp

@@ -1549,6 +1549,7 @@ QAST::Operations.add_core_pirop_mapping('unshift_n', 'unshift', '0Pn', :inlinabl
 QAST::Operations.add_core_pirop_mapping('splice', 'splice', '0PPii', :inlinable(1));
 QAST::Operations.add_core_pirop_mapping('islist', 'nqp_islist', 'IP', :inlinable(1));
 QAST::Operations.add_core_pirop_mapping('ishash', 'nqp_ishash', 'IP', :inlinable(1));
+QAST::Operations.add_core_pirop_mapping('isinvokable', 'is_invokable', 'IP', :inlinable(1));
 
 # repr-level aggregate operations
 QAST::Operations.add_core_pirop_mapping('r_atpos', 'repr_at_pos_obj', 'PPi', :inlinable(1));

t/nqp/11-sub.t

@@ -2,7 +2,7 @@
 
 # check subs
 
-say('1..12');
+say('1..14');
 
 sub one ( ) {
     say("ok 1 # sub def and call");
@@ -75,3 +75,6 @@ say('ok ', Qstuff());
 
 sub term:sym<self>() { 12 }
 say('ok ', term:sym<self>());
+
+say( (!nqp::isinvokable(sub() {}) ?? 'ok 13' !! 'no 13' ) ~ '  nqp::isinvokable on sub');
+say( (!nqp::isinvokable(666) ?? 'ok 14' !! 'no 14' ) ~ '  nqp::isinvokable on non sub');