Read_Alpha


Purpose   Provides single line input of alpha characters, offering full
          line editing features, optional prompt display and optional box
          drawing.

Decln.    Read_Alpha(X,Y,L:byte;Prompt:strScreen;Box:byte;Var
          Str:strscreen);

Remarks   X, Y are the coordinates of the first character of the prompt or
          the first character of the input field if the prompt is null.
          L is the length of the input line.
          Prompt is an optional prompt. The prompt is normally displayed to
          the left of the input field. If the prompt begins with a carat
          '' and the box border is on, the prompt is drawn in the upper
          box border. If the prompt begins with an underscore '_' and the
          box border is on, the prompt is drawn in the lower box border.
          Set the prompt to a null '' if no prompt is required.
          Box is a box code. The codes are the same as for the Box
          procedure in FastTTT5. To suppress the box, use a code of zero.
          Str is the string that will be updated with the user's input.

          The user will only be able to input normal alphabetic characters
          and spaces.

          The display characteristics of the input line are contained in
          the global variable RTTT.

          The global variable R_Char is updated with the last character
          pressed by the user. This can be checked to see how the user
          terminated input, e.g. Esc, Up Arrow, etc.

Example

VAR
  TTT : STRSCREEN;
BEGIN
    TTT := '';
    READ_ALPHA(5,10,40,'ENTER YOUR NAME > ',1,TTT);
END;