compiler: implement Oracle contract wrapper

pkg/interop/native/oracle/oracle.go

@@ -0,0 +1,16 @@
+package oracle
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/interop"
+	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
+)
+
+// Hash represents Oracle contract hash.
+const Hash = "\xee\x80\x4c\x14\x29\x68\xd4\x78\x8b\x8a\xff\x51\xda\xde\xdf\xcb\x42\xe7\xc0\x8d"
+
+// Request represents `request` method of Oracle native contract.
+func Request(url string, filter []byte, cb string, userData interface{}, gasForResponse int) {
+	contract.Call(interop.Hash160(Hash), "request",
+		contract.WriteStates|contract.AllowNotify,
+		url, filter, cb, userData, gasForResponse)
+}