(* The lexical analyzer for lexer definitions. Bootstrapped! *) {open Fnlib Syntax Grammar Scan_aux;} rule main = parse    [` ` `\n` `\r` `\t` ] +    { main lexbuf }  | "(*"    { (comment_depth := 1; comment lexbuf; main lexbuf) }  | "*)"      { raise Lexical_error "unmatched comment bracket" }  | [`A`-`Z` `a`-`z`] ( [ `A`-`Z` `a`-`z` `0`-`9` `_` `'`] )*    { case getLexeme lexbuf of        "rule"  => Trule      | "parse" => Tparse      | "and"   => Tand      | "eof"   => Teof      | "let"   => Tlet      | s       => Tident s }  | `"`    { (reset_string_buffer();       string lexbuf;       Tstring(get_stored_string())) }  | "`"    { Tchar(char lexbuf) }  | `{`    { let val n1 = getLexemeEnd lexbuf          val () = brace_depth := 1          val n2 = action lexbuf      in Taction(Location(n1, n2)) end }  | `=`  { Tequal }  | ";"  { Tend }  | `|`  { Tor }  | `_`  { Tunderscore }  | "eof"  { Teof }  | `[`  { Tlbracket }  | `]`  { Trbracket }  | `*`  { Tstar }  | `?`  { Tmaybe }  | `+`  { Tplus }  | `(`  { Tlparen }  | `)`  { Trparen }  | `^`  { Tcaret }  | `-`  { Tdash }  | (eof | `\026`)    { raise Lexical_error "unterminated lexer definition" }  | _    { raise Lexical_error             ("illegal character #" ^ makestring(getLexeme lexbuf)) } and action = parse    `{`        { (incr brace_depth; action lexbuf) }  | `}`        { (decr brace_depth;           if !brace_depth = 0 then             getLexemeStart lexbuf           else             action lexbuf) }  | `"`    { (reset_string_buffer();       string lexbuf;       reset_string_buffer();       action lexbuf) }  | "(*"    { (comment_depth := 1; comment lexbuf; action lexbuf) }  | "*)"      { raise Lexical_error "unmatched comment bracket" }  | (eof | `\026`)    { raise Lexical_error "unterminated action" }  | _    { action lexbuf } and string = parse    `"`    { () }  | `\\` [` ` `\t` `\n` `\r`]+ `\\`      { string lexbuf }  | `\\` [`\\` `"` `n` `t` `b` `r`]    { (store_string_char(char_for_backslash(getLexemeChar lexbuf 1));       string lexbuf) }  | `\\` `^` [`@`-`_`]      { (store_string_char(           Char.chr(Char.ord(getLexemeChar lexbuf 2) - 64));         string lexbuf) }  | `\\` [`0`-`9`] [`0`-`9`] [`0`-`9`]    { let val code = char_for_decimal_code lexbuf 1 in        if Char.ord code >= 256 then          raise Lexical_error "character code in string > 255"        else ();        store_string_char code;        string lexbuf      end }  | `\\`      { raise Lexical_error "ill-formed escape sequence in string" }  | (eof | `\026`)    { raise Lexical_error "unterminated string" }  | [`\001`-`\031` `\127` `\255`]      { raise Lexical_error "invalid character in string" }  | _    { (store_string_char(getLexemeChar lexbuf 0);       string lexbuf) } and char = parse    `\\` [`\\` `\`` `n` `t` `b` `r`] "`"    { char_for_backslash (getLexemeChar lexbuf 1) }  | `\\` `^` [`@`-`_`] "`"      { Char.chr(Char.ord(getLexemeChar lexbuf 2) - 64) }  | `\\` [`0`-`9`] [`0`-`9`] [`0`-`9`] "`"    { let val code = char_for_decimal_code lexbuf 1 in        if Char.ord code >= 256 then          raise Lexical_error "character code in string > 255"        else ();        code      end }  | `\\`      { raise Lexical_error "ill-formed escape sequence in character constant" }  | (eof | `\026`)    { raise Lexical_error "unterminated character constant" }  | [`\001`-`\031` `\127` `\255`]      { raise Lexical_error "invalid character in character constant" }  | _ "`"    { getLexemeChar lexbuf 0 }  | _    { raise Lexical_error "ill-formed character constant" } and comment = parse    "(*"    { (incr comment_depth; comment lexbuf) }  | "*)"    { (decr comment_depth;       if !comment_depth = 0 then () else comment lexbuf) }  | (eof | `\026`)    { raise Lexical_error "unterminated comment" }  | _    { comment lexbuf };