Syntax error in KSY breaks compilation, but does not change exit code in shell
Syntax error in KSY breaks compilation, but does not change exit code in shell. 

Thus, an usual linux command-line construct like this

    kaitai-struct-compiler syntaxdef.ksy -t python   &&   python test.py

executes the python command always, even if ```syntaxdef.ksy``` is invalid. I guess the fix is just a few lines of code.