Fix bug with function definitions

Signed-off-by: Ben Sherman <bentshermann@gmail.com>

Author: bentsherman

modules/compiler/src/main/java/script/ast/FunctionNode.java

@@ -15,6 +15,8 @@
  */
 package nextflow.script.ast;
 
+import java.lang.reflect.Modifier;
+
 import org.codehaus.groovy.ast.ClassNode;
 import org.codehaus.groovy.ast.MethodNode;
 import org.codehaus.groovy.ast.Parameter;
@@ -29,12 +31,12 @@ public class FunctionNode extends MethodNode {
     public final String documentation;
 
     public FunctionNode(String name, ClassNode returnType, Parameter[] parameters, Statement code) {
-        super(name, 0, returnType, parameters, ClassNode.EMPTY_ARRAY, code);
+        super(name, Modifier.PUBLIC, returnType, parameters, ClassNode.EMPTY_ARRAY, code);
         this.documentation = null;
     }
 
     public FunctionNode(String name, String documentation) {
-        super(name, 0, null, Parameter.EMPTY_ARRAY, ClassNode.EMPTY_ARRAY, EmptyStatement.INSTANCE);
+        super(name, Modifier.PUBLIC, null, Parameter.EMPTY_ARRAY, ClassNode.EMPTY_ARRAY, EmptyStatement.INSTANCE);
         this.documentation = documentation;
     }
 }