0. Starting with Click 2.0, it’s possible to provide a function that is used for normalizing tokens. Tokens are option names, choice values, or command values. This can be used to implement case insensitive The default is ['--help']. • token_normalize_func – an optional function that is used to normalize tokens (op- tions, choices, etc.). This for instance can be used to implement case insensitive behavior terminal (None is autodetection). token_normalize_func = None An optional normalization function for tokens. This is options, choices, commands etc. 2.1.6 Types click.STRING = STRING A unicode string parameter

bison */ %{ #include extern int yylex(void); extern int yyerror(char *); %} /* declare tokens */ %token NUMBER %token OP_ADD OP_SUB OP_MUL OP_RGT OP_LFT OP_EQU %% calc: | calc exp OP_EQU {