Tutorials > ocamllex tutorial > Examples > Word count

Word count

This example shows the number of lines, words and characters of the given file if the filename is given, or of the standard input if no command arguments are given.

{ }

rule count lines words chars = parse
  | '\n'		{ count (lines+1) words (chars+1) lexbuf }
  | [^ ' ' '\t' '\n']+ as word
  		{ count lines (words+1) (chars+ String.length word) lexbuf }
  | _		{ count lines words (chars+1) lexbuf }
  | eof		{ (lines, words, chars) }

{
  let main () =
    let cin =
      if Array.length Sys.argv > 1
      then open_in Sys.argv.(1)
      else stdin
    in
    let lexbuf = Lexing.from_channel cin in
    let (lines, words, chars) = count 0 0 0 lexbuf in
    Printf.printf "%d lines, %d words, %d chars\n" lines words chars

  let _ = Printexc.print main ()
}