MODULE Tabs;

CONST
    MAXLINE = 1000; (* or whatever *)

TYPE
    TabType* = ARRAY MAXLINE OF BOOLEAN;
    
(* TabPos -- return TRUE if col is a tab stop *)
PROCEDURE TabPos*(col : INTEGER; VAR tabstops : TabType) : BOOLEAN;
  VAR res : BOOLEAN;
BEGIN
  res := FALSE; (* Initialize our internal default return value *)
  IF (col >= MAXLINE) THEN
    res := TRUE;
  ELSE
    res := tabstops[col];
  END;
  RETURN res
END TabPos;

(* SetTabs -- set initial tab stops *)
PROCEDURE SetTabs*(VAR tabstops: TabType);
CONST
  TABSPACE = 4; (* 4 spaces per tab *) 
VAR
  i : INTEGER;
BEGIN
  (* NOTE: Arrays in Oberon start at zero, we want to
     stop at the last cell *)
  FOR i := 0 TO (MAXLINE - 1) DO
    tabstops[i] := (i MOD TABSPACE = 0);
  END;
END SetTabs;

END Tabs.

This module is used by Detab.Mod and Entab.Mod
and provides for common type definitions and code reuse.

NOTE: We export TabType, TabPos and SetTabs. Everything else
is private to this module.