Denso BHT-BASIC 100 SERIES, Руководство программиста

Страница: 15 / 577

Chapter 1. Software Overview for the BHT
7
■
Defining and declaring user-defined functions more easily
BHT-BASIC 3.5 has added
FUNCTION
…
END FUNCTION
,
SUB
...
END SUB
, and
DECLARE
statements. With the former two, you may easily define your own functions— FUNCTION and
SUB . With the latter one, you may declare FUNCTION and SUB functions which are defined
in any other source files.
■ Scoping variables to be local or global
(with
PRIVATE or GLOBAL statement)
In BHT-BASIC 3.5, work variables and register variables may have "scope" to restrict the
access to them.
With the PRIVATE statement, you may declare a variable to be local. A local variable can only
be accessed by any routine in a file where it is defined. With the GLOBAL statement, you may
declare a variable to be global. A global variable can be accessed by any routine in a program.
However, a variable used inside the
FUNCTION
or
SUB
function without declaration is avail-
able only within a function where it is defined.
Since local variables are restricted in access, you can define them with a same name in differ-
ent files.
For details about the scope of variables, refer to Chapter 5, Section 5.5.
■
Defining constants
BHT-BASIC 3.5 can define constants.