let disp_help () = pl "m.E.M.E - Minimalist Evaluator for Mathematical Expressions\n\nusage: calc [options] [mode]\n\n modes:\n +command-line (c) sequentially evaluate command-line arguments\n +stdin (s) evaluate expressions from standard input\n +replace (r) search and replace expressions inside a line (on stdin)\n\n options: (modes c and s)\n --print-xp (pxp) reprint the unevaluated expression\n --print-newline (pn) goto newline before printing the result\n --print-unit (pu) print units, ie. stand-alone assignments\n --print-symbol (ps) print a symbol before the result\n\n options (mode s)\n --display-welcome (dw) \n Display the welcome message at beginning of session\n\n options (modes s and r)\n --eval-now (en) xp1...xpN\n Evaluate a list of command-line expressions before processing stdin.\n \n options (mode r)\n --delimiters (del) <left del> <right del>\n Set the delimiters for mathematical expressions.\n\n options (all modes)\n --eval-file (ef) <str>\n Silently parse a file. Useful to define a bunch of variables.\n --unit-string (us) <str>\n Set the string representing a unit (pure side-effect evaluation)\n --print-errors (pe)\n The parser prints debug error messages on stderr\n --show-error (se)\n The parser prints a line with ^^^ where the error is\n --help\n Print this help page.\n"