Using the classic for loop from java like: for(int i = 0; i < 60;i++) { println i } produces the error: Script1.groovy: 67: Unexpected node type: TYPE found when expecting type: an identifier at line: 67 column: 32. File: Script1.groovy @ line 67, column 32. 1 Error Which is not very helpful for those who don't know it is not supported.. a nice error message at a minium would be good.. ideally it should dynamically inspect the AST and suggest what you should use