Equal to (==)
The ==
operator
checks for equality of two expressions or for two record variables.
Syntax 1: Expression comparison
expr == expr
Syntax 2: Record comparison
record1.* == record2.*
- expr can be any expression supported by the language.
- record1 and record2 are records with the same structure.
Usage
The ==
operator evaluates
whether two expressions or two records are identical.
A single
equal sign (=
) can be used as an alias for the ==
operator.
When comparing expressions using the first syntax, the result of the operator is
NULL
when one of the operands is NULL
.
First syntax applies to most data types, except complex types like BYTE
and
TEXT
.
When
comparing two records using the second syntax, the runtime system
compares all corresponding members of the records. If a pair of members
are different, the result of the operator is FALSE
.
When two corresponding members are NULL
, they are
considered as equal. This second syntax allows you to compare all
members of records, but records must have the same structure.
Example
MAIN
DEFINE n INTEGER
LET n=512
IF n==512 THEN
DISPLAY "The variable equals 512."
END IF
END MAIN