Add conversion between set and vector using 'as' keyword

NEWS

@@ -43,6 +43,11 @@ New Functionality
   modules by prefixing their names with ``::``. Previously, these required an
   explicit ``GLOBAL::`` prefix to be used. Using ``GLOBAL::`` has been deprecated.
 
+- The ``as`` keyword now supports casting between ``set`` and ``vector`` values
+  with the same element type. Converting ``set`` values with multiple index
+  values is not supported. We plan to extend the use of the ``as`` keyword to
+  support more type conversions in the future.
+
 Changed Functionality
 ---------------------
 

src/Val.cc

@@ -4262,9 +4262,74 @@ ValPtr cast_value_to_type(Val* v, Type* t)
 		return static_cast<Broker::detail::DataVal*>(dv.get())->castTo(t);
 		}
 
+	// Allow casting between sets and vectors if the yield types are the same.
+	if ( v->GetType()->IsSet() && IsVector(t->Tag()) )
+		{
+		auto set_type = v->GetType<SetType>();
+		auto indices = set_type->GetIndices();
+
+		if ( indices->GetTypes().size() > 1 || ! indices->IsPure() )
+			return nullptr;
+
+		auto ret_type = IntrusivePtr<VectorType>{NewRef{}, t->AsVectorType()};
+		auto ret = make_intrusive<VectorVal>(ret_type);
+
+		auto lv = v->AsTableVal()->ToPureListVal();
+		auto n = lv->Length();
+
+		for ( int i = 0; i < n; ++i )
+			ret->Assign(i, lv->Idx(i));
+
+		return ret;
+		}
+	else if ( IsVector(v->GetType()->Tag()) && t->IsSet() )
+		{
+		auto ret_type = IntrusivePtr<TableType>{NewRef{}, t->AsSetType()};
+		auto ret = make_intrusive<TableVal>(ret_type);
+
+		auto vv = v->AsVectorVal();
+		size_t size = vv->Size();
+
+		for ( size_t i = 0; i < size; i++ )
+			{
+			auto ve = vv->ValAt(i);
+			ret->Assign(std::move(ve), nullptr);
+			}
+
+		return ret;
+		}
+
 	return nullptr;
 	}
 
+static bool can_cast_set_and_vector(const Type* t1, const Type* t2)
+	{
+	const TableType* st = nullptr;
+	const VectorType* vt = nullptr;
+
+	if ( t1->IsSet() && IsVector(t2->Tag()) )
+		{
+		st = t1->AsSetType();
+		vt = t2->AsVectorType();
+		}
+	else if ( IsVector(t1->Tag()) && t2->IsSet() )
+		{
+		st = t2->AsSetType();
+		vt = t1->AsVectorType();
+		}
+
+	if ( st && vt )
+		{
+		auto set_indices = st->GetIndices();
+		if ( set_indices->GetTypes().size() > 1 || ! set_indices->IsPure() )
+			return false;
+
+		return same_type(set_indices->GetPureType(), vt->Yield());
+		}
+
+	return false;
+	}
+
 bool can_cast_value_to_type(const Val* v, Type* t)
 	{
 	// Note: when changing this function, adapt all three of
@@ -4288,6 +4353,10 @@ bool can_cast_value_to_type(const Val* v, Type* t)
 		return static_cast<const Broker::detail::DataVal*>(dv.get())->canCastTo(t);
 		}
 
+	// Allow casting between sets and vectors if the yield types are the same.
+	if ( can_cast_set_and_vector(v->GetType().get(), t) )
+		return true;
+
 	return false;
 	}
 
@@ -4307,6 +4376,10 @@ bool can_cast_value_to_type(const Type* s, Type* t)
 		// will.
 		return true;
 
+	// Allow casting between sets and vectors if the yield types are the same.
+	if ( can_cast_set_and_vector(s, t) )
+		return true;
+
 	return false;
 	}
 

testing/btest/Baseline/language.vector-set-conversions-errors/.stderr

@@ -0,0 +1,4 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+error in <...>/vector-set-conversions-errors.zeek, line 8: cast not supported (v1 as set[addr])
+error in <...>/vector-set-conversions-errors.zeek, line 15: cast not supported (s2 as vector of addr)
+error in <...>/vector-set-conversions-errors.zeek, line 22: cast not supported (s3 as vector of port)

testing/btest/Baseline/language.vector-set-conversions-errors/out

@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.

testing/btest/Baseline/language.vector-set-conversions/.stderr

@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.

testing/btest/Baseline/language.vector-set-conversions/out

@@ -0,0 +1,25 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+vector to set
+[1, 1, 1, 2, 2, 3, 3, 4]
+{
+4,
+2,
+3,
+1
+}
+
+set to vector (count)
+{
+4,
+2,
+3,
+1
+}
+[4, 2, 3, 1]
+
+set to vector (port)
+{
+23/tcp,
+21/tcp
+}
+[23/tcp, 21/tcp]

testing/btest/language/vector-set-conversions-errors.zeek

@@ -0,0 +1,24 @@
+# @TEST-DOC: Test error cases while converting between sets and vectorswith the 'as' keyword
+# @TEST-EXEC-FAIL: zeek -b %INPUT > out
+# @TEST-EXEC: btest-diff out
+# @TEST-EXEC: TEST_DIFF_CANONIFIER="$SCRIPTS/diff-remove-abspath" btest-diff .stderr
+
+print("vector to set: type mismatch");
+local v1 = vector(1, 1, 1, 2, 2, 3, 3, 4);
+local s1 = v1 as set[addr];
+print(v1);
+print(s1);
+
+print("");
+print("set to vector: type mismatch");
+local s2 = set(1, 2, 3, 4);
+local v2 = s2 as vector of addr;
+print(s2);
+print(v2);
+
+print("");
+print("set to vector: multiple indices");
+local s3: set[port,string] = { [21/tcp, "ftp"], [23/tcp, "telnet"] };
+local v3 = s3 as vector of port;
+print(s3);
+print(v3);

testing/btest/language/vector-set-conversions.zeek

@@ -0,0 +1,24 @@
+# @TEST-DOC: Tests converting between sets and vectors with the 'as' keyword
+# @TEST-EXEC: zeek -b %INPUT > out
+# @TEST-EXEC: btest-diff out
+# @TEST-EXEC: btest-diff .stderr
+
+print("vector to set");
+local v1 = vector(1, 1, 1, 2, 2, 3, 3, 4);
+local s1 = v1 as set[count];
+print(v1);
+print(s1);
+
+print("");
+print("set to vector (count)");
+local s2 = set(1, 2, 3, 4);
+local v2 = s2 as vector of count;
+print(s2);
+print(v2);
+
+print("");
+print("set to vector (port)");
+local s3 = set(21/tcp, 23/tcp);
+local v3 = s3 as vector of port;
+print(s3);
+print(v3);