35 lines
833 B
OCaml
35 lines
833 B
OCaml
{
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open Lexing
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open Oflan
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exception SyntaxError of string
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let next_line lexbuf =
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let pos = lexbuf.lex_curr_p in
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lexbuf.lex_curr_p <-
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{ pos with pos_bol = lexbuf.lex_curr_pos;
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pos_lnum = pos.pos_lnum + 1
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}
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}
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let digit = ['0'-'9']
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let digits = digit*
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let alpha = ['a'-'z' 'A'-'Z']
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let ident = (alpha) (alpha|digit|'_')* (* regex for identifier *)
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let whitespace = [' ' '\t']+
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let newline = '\r' | '\n' | "\r\n"
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let int = digits
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rule read =
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parse
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| whitespace { read lexbuf }
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| newline { next_line lexbuf; read lexbuf }
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| int { Int (int_of_string (Lexing.lexeme lexbuf))}
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| "let" { Let }
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| ident { Ident (Lexing.lexeme lexbuf) }
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| '=' { Equal }
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| '(' { LParen }
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| 'R' { RParen }
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| eof { Eof }
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| _ { raise (SyntaxError ("Unexpected char: " ^ Lexing.lexeme lexbuf)) } |