Temporary override for Sys.time function since we do not handle POSIXct and...

Temporary override for Sys.time function since we do not handle POSIXct and POSIXlt objects at the moment.

com.oracle.truffle.r.nodes.builtin/src/com/oracle/truffle/r/nodes/builtin/base/R/datetime_overrides.R

+#  File src/library/base/R/datetime.R
+#  Part of the R package, http://www.R-project.org
+#
+#  Copyright (C) 1995-2014 The R Core Team
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  A copy of the GNU General Public License is available at
+#  http://www.r-project.org/Licenses/
+
+# TODO fix the problem with .POSIXct - the following implementations
+# of format are obviously wrong but it's better than raising an exception
+# whenever Sys.time() is called (and it's mostly used for printing timestamps)
+
+format.POSIXlt <- function(x, format = "", usetz = FALSE, ...)
+{
+    format.default(x)
+}
+
+format.POSIXct <- function(x, format = "", tz = "", usetz = FALSE, ...)
+{
+    format.default(x)
+}
+

com.oracle.truffle.r.test/src/com/oracle/truffle/r/test/library/base/TestSimpleBuiltins.java

@@ -730,6 +730,8 @@ public class TestSimpleBuiltins extends TestBase {
         assertEval(Ignored.Unknown, "{ as.character(list(list(c(\"hello\", \"hi\")))) }");
         assertEval(Ignored.Unknown, "{ as.character(list(c(2L, 3L))) }");
         assertEval(Ignored.Unknown, "{ as.character(list(c(2L, 3L, 5L))) }");
+
+        assertEval("{ x<-as.character(Sys.time()) }");
     }
 
     @Test