14.4.5.1 Operators
Operators must be defined on values of specific types. For instance,
+ is defined on numbers, but not on structures. Operators are
often defined on groups of types. For the purposes of Modula-2, the
following definitions hold:
- Integral types consist of
INTEGER, CARDINAL, and
their subranges.
- Character types consist of
CHAR and its subranges.
- Floating-point types consist of
REAL.
- Pointer types consist of anything declared as
POINTER TO
type.
- Scalar types consist of all of the above.
- Set types consist of
SET and BITSET types.
- Boolean types consist of
BOOLEAN.
The following operators are supported, and appear in order of
increasing precedence:
,- Function argument or array index separator.
:=- Assignment. The value of var
:= value is
value.
<, >- Less than, greater than on integral, floating-point, or enumerated
types.
<=, >=- Less than or equal to, greater than or equal to
on integral, floating-point and enumerated types, or set inclusion on
set types. Same precedence as
<.
=, <>, #- Equality and two ways of expressing inequality, valid on scalar types.
Same precedence as
<. In gdb scripts, only <> is
available for inequality, since # conflicts with the script
comment character.
IN- Set membership. Defined on set types and the types of their members.
Same precedence as
<.
OR- Boolean disjunction. Defined on boolean types.
AND, &- Boolean conjunction. Defined on boolean types.
@- The gdb “artificial array” operator (see Expressions).
+, -- Addition and subtraction on integral and floating-point types, or union
and difference on set types.
*- Multiplication on integral and floating-point types, or set intersection
on set types.
/- Division on floating-point types, or symmetric set difference on set
types. Same precedence as
*.
DIV, MOD- Integer division and remainder. Defined on integral types. Same
precedence as
*.
-- Negative. Defined on
INTEGER and REAL data.
^- Pointer dereferencing. Defined on pointer types.
NOT- Boolean negation. Defined on boolean types. Same precedence as
^.
.RECORD field selector. Defined on RECORD data. Same
precedence as ^.
[]- Array indexing. Defined on
ARRAY data. Same precedence as ^.
()- Procedure argument list. Defined on
PROCEDURE objects. Same precedence
as ^.
::, .- gdb and Modula-2 scope operators.
Warning: Set expressions and their operations are not yet supported, so gdb
treats the use of the operator IN, or the use of operators
+, -, *, /, =, , <>, #,
<=, and >= on sets as an error.