LETTER
state &= ~LETTER;
state |= LETTER;
case NAMING | LETTER:
%token <astr> LETTER
function_header : DEFINE LETTER LPAR
parameter_list : LETTER
| LETTER LBRACKET RBRACKET
| parameter_list COMMA LETTER
| parameter_list COMMA LETTER LBRACKET RBRACKET
define_list : LETTER
| LETTER LBRACKET RBRACKET
| define_list COMMA LETTER
| define_list COMMA LETTER LBRACKET RBRACKET
| argument_list COMMA LETTER LBRACKET RBRACKET
| LETTER LPAR opt_argument_list RPAR
: LETTER
| LETTER LBRACKET expression RBRACKET