compiler/interop: improve conversion to bytes interops

Allow to convert to both `Buffer` and `ByteString`
and explicitly mention VM types. Rename `ToByteArray` to `ToBytes`
to avoid ambiguity.

pkg/compiler/analysis.go

@@ -18,7 +18,7 @@ var (
 	// Custom builtin utility functions.
 	customBuiltins = []string{
 		"FromAddress", "Equals", "Remove",
-		"ToBool", "ToByteArray", "ToInteger",
+		"ToBool", "ToBytes", "ToString", "ToInteger",
 	}
 )
 

pkg/compiler/convert_test.go

@@ -17,7 +17,7 @@ func getFunctionName(typ string) string {
 	case "bool":
 		return "Bool"
 	case "[]byte":
-		return "ByteArray"
+		return "Bytes"
 	case "int":
 		return "Integer"
 	}

pkg/interop/convert/convert.go

@@ -6,11 +6,16 @@ func ToInteger(v interface{}) int {
 	return v.(int)
 }
 
-// ToByteArray converts it's argument to a ByteArray.
+// ToBytes converts it's argument to a Buffer VM type.
-func ToByteArray(v interface{}) []byte {
+func ToBytes(v interface{}) []byte {
 	return v.([]byte)
 }
 
+// ToString converts it's argument to a ByteString VM type.
+func ToString(v interface{}) string {
+	return v.(string)
+}
+
 // ToBool converts it's argument to a Boolean.
 func ToBool(v interface{}) bool {
 	return v.(bool)