gdb: Fortran Operators

 
 15.4.6.1 Fortran Operators and Expressions
 ..........................................
 
 Operators must be defined on values of specific types.  For instance,
 '+' is defined on numbers, but not on characters or other non-
 arithmetic types.  Operators are often defined on groups of types.
 
 '**'
      The exponentiation operator.  It raises the first operand to the
      power of the second one.
 
 ':'
      The range operator.  Normally used in the form of array(low:high)
      to represent a section of array.
 
 '%'
      The access component operator.  Normally used to access elements in
      derived types.  Also suitable for unions.  As unions aren't part of
      regular Fortran, this can only happen when accessing a register
      that uses a gdbarch-defined union type.