DEFINITION MODULE TextIO;

  (* Input and output of character and string types over
     specified channels.  The read result is of the type
     IOConsts.ReadResults.
  *)

IMPORT IOChan;

  (* The following procedures do not read past line marks *)

PROCEDURE ReadChar (cid: IOChan.ChanId; VAR ch: CHAR);
  (* If possible, removes a character from the input stream
     cid and assigns the corresponding value to ch.  The
     read result is set to the value allRight, endOfLine, or
     endOfInput.
  *)

PROCEDURE ReadRestLine (cid: IOChan.ChanId; VAR s: ARRAY OF CHAR);
  (* Removes any remaining characters from the input stream
     cid before the next line mark,  copying to s as many as
     can be accommodated as a string value.  The read result is
     set to the value allRight, outOfRange, endOfLine, or
     endOfInput.
  *)

PROCEDURE ReadString (cid: IOChan.ChanId; VAR s: ARRAY OF CHAR);
  (* Removes only those characters from the input stream cid
     before the next line mark that can be accommodated in s
     as a string value, and copies them to s.  The read result
     is set to the value allRight, endOfLine, or endOfInput.
  *)

PROCEDURE ReadToken (cid: IOChan.ChanId; VAR s: ARRAY OF CHAR);
  (* Skips leading spaces, and then removes characters from
     the input stream cid before the next space or line mark,
     copying to s as many as can be accommodated as a string
     value.  The read result is set to the value allRight,
     outOfRange, endOfLine, or endOfInput.
  *)

  (* The following procedure reads past the next line mark *)

PROCEDURE SkipLine (cid: IOChan.ChanId);
  (* Removes successive items from the input stream cid up
     to and including the next line mark, or until the end
     of input is reached.  The read result is set to the
     value allRight, or endOfInput.
  *)

  (* Output procedures *)

PROCEDURE WriteChar (cid: IOChan.ChanId; ch: CHAR);
  (* Writes the value of ch to the output stream cid. *)

PROCEDURE WriteLn (cid: IOChan.ChanId);
  (* Writes a line mark to the output stream cid. *)

PROCEDURE WriteString (cid: IOChan.ChanId; s: ARRAY OF CHAR);
  (* Writes the string value in s to the output stream cid. *)

END TextIO.