Ordinal routines provide information on the ordered sequence  of
  values.

1  –  LOWER

  This function returns the lower bound  for  ordinal  types,  SET
  base types, and array indexes.

  Syntax:

     LOWER( x [[, n]] )

  The parameter 'x'  is  a  type  identifier  or  variable  of  an
  ordinal,  SET,  or  ARRAY type.  The parameter 'n' is an integer
  constant that denotes a dimension of 'x', if 'x'  is  an  array.
  If  'x' is an array and if you omit the 'n', VSI Pascal uses the
  default value 1.  If 'x' is an array, LOWER  returns  the  lower
  bound  of  the nth dimension of 'x'.  If 'x' is an ordinal type,
  LOWER returns the lower bound or smallest value.  If  'x'  is  a
  SET, LOWER returns the lower bound of the SET base type.

2  –  PRED

  The PRED function returns  the  value  preceding  the  parameter
  according to the parameter's data type.

  Syntax:

     PRED( x )

  The parameter 'x' can be of any  ordinal  type;  however,  there
  must be a predecessor value for 'x' in the type.

3  –  SUCC

  The SUCC function returns the value that succeeds the  parameter
  according to the parameter's data type.

  Syntax:

     SUCC( x )

  The parameter 'x' can be of any  ordinal  type;  however,  there
  must be a successor value for 'x' in the type.

4  –  UPPER

  The UPPER function returns the upper bound  for  ordinal  types,
  SET base types, and array indexes.

  Syntax:

     UPPER( x [[, n]] )

  The parameter 'x'  is  a  type  identifier  or  variable  of  an
  ordinal,  SET,  or  ARRAY type.  The parameter 'n' is an integer
  constant that denotes a dimension of 'x', if 'x'  is  an  array.
  If  'x' is an array and if you omit the 'n', VSI Pascal uses the
  default value 1.  If 'x' is an array, UPPER  returns  the  upper
  bound  of  the nth dimension of 'x'.  If 'x' is an ordinal type,
  UPPER returns the upper bound or largest value.   If  'x'  is  a
  SET, UPPER returns the upper bound of the SET base type.