usage:
test_parser [options]... <filename.nit>...
+ test_parser -e [options]... <text>...
+ test_parser -i [options]...
options:
-n do not print anything
-l only lexer
-p lexer and parser (default)
-e instead on files, each argument is a content to parse
+ -i tree to parse are read interactively
-h print this help