PARSER

%token <bool> BOOL
%token AND OR NOT
%token LPAREN RPAREN
%token EOL

%left AND OR         /* lowest precedence */
%nonassoc NOT        /* highest precedence */

%start <bool> main

%%

main:
| e = expr EOL
    { e }

expr:
| i = BOOL
    { i }
| LPAREN e = expr RPAREN
    { e }
| e1 = expr AND e2 = expr
    { e1 && e2 }
| e1 = expr OR e2 = expr
    { e1 || e2 }
| NOT e = expr %prec NOT
    { not e }

LEXER


{
  open Parser

  exception Error of string

}

rule line = parse
| ([^'\n']* '\n') as line
    { line }
| eof
    { exit 0 }

and token = parse
| [' ' '\t']
    { token lexbuf }
| '\n'
    { EOL }
| "AND"
    { AND }
| "OR"
    { OR }
| "NOT"
    { NOT }
| '('
    { LPAREN }
| ')'
    { RPAREN }
| ['a'-'z' 'A'-'Z' '_' '0'-'9']+ as i
    { BOOL (Hashtbl.mem Globals.flags_tbl i) }
| eof
    { exit 0 }
| _
    { raise (Error (Printf.sprintf "At offset %d: unexpected character.\n" (Lexing.lexeme_start lexbuf))) }