Block implementation making some? progress...
Block implementation good. parseBlock() checks for scanner.done() and if 'end' kwid reached for 'begin' block 'end' nodes.
parseRelop, parseBoolExpr largely implemented. Testing required!
NodeIfThen and it's parsing done... but:

program = "if 10>5 then wr 1;"

Exception in thread "main" java.lang.NullPointerException
	at NodeBoolExpr.eval(NodeBoolExpr.java:13)
	at NodeIfThen.eval(NodeIfThen.java:22)
	at NodeStmt.eval(NodeStmt.java:10)
	at NodeBlock.eval(NodeBlock.java:17)
	at Interpreter.main(Interpreter.java:10)
Java Result: 1