Bool is an intrinsic type of TypeCobol . A bool is limited to two values (TRUE and FALSE); this is not possible with current COBOL 85 syntax. Format :

01 Identifier TYPE Bool.

Main usages are:

SET Identifier to TRUE
Set Identifier to false
if identifier
if not identifier
when identifier

As content of a boolean should be restricted to values ‘TRUE’ and ‘FALSE’ , TypeCobol parser must include specifics controls for Bool type :

• TypeCobol parser should prevent usage of Move to the elementary item
• (except MOVE from another Boolean or, for TypeCOBOL extension, MOVE TRUE or MOVE FALSE)
• Typecobol should also warn when using a statement that might alter the boolean values
• Move to a group containing a boolean
• Initialize of a group with Booleans

You can set a default value for bool just like you do in Cobol 85:

01 var1 TYPE Bool value true.
01 var2 TYPE Bool value false.

By default, the value is false.

In Cobol 85, bool is translated to:

01 Identifier-value PIC X value low-value.
88 Identifier value ‘T’.
88 Identifier-false value 'F' X'00' thru 'S'
                              'U' thru X'FF'.

SET Identifier to TRUE	remains the same in COBOL
SET Identifier to FALSE	will be translated as ‘SET Identifier-false’ to TRUE’

Note that in Cobol 2002, you can use "set to false", so type bool is translated to:

01               pic X value low-value.
  88 Identifier        value 'T' false 'F'.