VMS Help FORTRAN, Data, Expressions  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  An expression represents a single value.  An expression can consist
  of a single constant, variable, record element, array element, or
  function reference; or combinations of these data items plus
  certain other elements, called operators.  Operators specify
  computations to be performed on the values of the data items and a
  single result is obtained.

  Expressions are classified as arithmetic, character, relational, or
  logical.  Arithmetic expressions produce numeric values; character
  expressions produce character values; and relational and logical
  expressions produce logical values.

  The data components of an expression must be compatible and must be
  joined by compatible operators.  Expressions are evaluated one
  operator at a time according to the rules of precedence.  The
  ranking assigned to each data type is as follows:

    Data Type                    Ranking
    ---------                    -------
    BYTE, LOGICAL*1, INTEGER*1    1 (lowest)
    LOGICAL*2                     2
    LOGICAL*4                     3
    INTEGER*2                     4
    INTEGER*4                     5
    REAL*4 (REAL)                 6
    REAL*8 (DOUBLE PRECISION)     7
    REAL*16                       8
    COMPLEX*8 (COMPLEX)           9
    COMPLEX*16 (DOUBLE COMPLEX)  10 (highest)

  Additional Information (explode) :

• Arithmetic
• Character
• Logical
• Relational