as usualwe can also test and use the system interactively to work through more of its utilityc:\pp \lang\parserpython import parser parser parser( parse(' ' error cases are trapped and reported in fairly friendly fashion (assuming users think in zero-based terms) parse(' ''ais undefined at column = = parse(' + + ''ais undefined at column = + + = parse(' $'lexical error at column = = parse(' 'syntax error at column = = parse(' ( 'syntax error at column = ( = parse(' ' parse(' / 'syntax error at column = / = division change custom language parsers