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Standard Pascal requires that case constants be specified individually. When the constant ranges extension is enabled, you can use constant ranges to specify a number of consecutive case constants. To use a constant range you specify the first constant in the range, and the last constant in the range, separated by .. as follows:

   first..last

You could use the constant range

   1..5

to specify the following case constants

   1, 2, 3, 4, 5

For example suppose c is a variable of char type and you want to use a case statement to write the word Letter if c contains a letter, and the word Digit if c contains a digit, then you could specify each case constant individually as follows:

   case c of
      'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
      'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
      'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
     : write('Letter');
      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
     : write('Digit');
   end;

Or you could use constant ranges like the following:

   case c of
      'a'..'z', 'A'..'Z'
     : write('Letter');
      '0'..'9'
     : write('Digit');
   end;

Constant ranges can be used in case statement, like in the example above, and in variant record types.

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