SPI Programming Manual (G06.24+, H06.03+, J06.03+)

Summary of DDL for SPI
SPI Programming Manual—427506-006
B-2
General Language Rules for DDL
You can make the information in the DDL definition file available to the system
procedures that derive display text from SPI messages. The DDL information helps the
EMSTEXT procedure and the SPI_BUFFER_FORMAT procedures produce more
readable display text. EMSTEXT presents event messages to operators. The
SPI_BUFFER_FORMAT procedures help Inspect to display SPI messages.
To make DDL information available at run time to the formatting procedures, you write
a template source file. This file enables the template compiler to encode DDL-clause
information in template form. For information about how to write and compile a
template source file, see the
DSM Template Services Manual .
General Language Rules for DDL
In DDL (as in TAL, COBOL, and TACL, though not in C), alphabetic characters in
names and keywords are not case-sensitive; that is, corresponding uppercase and
lowercase letters are equivalent. The convention used in the SPI manuals was chosen
to emphasize the SPI definition names, because these names, rather than the DDL
keywords, are of primary importance. The DDL keywords here merely serve as part of
the notation.
Periods in DDL serve as separators. They separate one statement from the next; they
also separate subdivisions of a DEF statement. Blanks, carriage returns, and tab
characters can occur within a statement or a statement subdivision. Therefore, a
statement or statement subdivision can continue over several lines.
DEFINITION (DEF) Statement
The DEFINITION statement (shortened here to its legal abbreviation DEF) defines the
structure of a data item or a group of items. It specifies the name, data type, and other
characteristics of each data item or group. The DDL compiler translates a DEF
statement into a declaration of an equivalent data structure in TAL, C, COBOL, and
TACL.
The examples in Figure B-1
on page B-3 show the use of the DEF statement, and are
referred to in descriptions throughout this section.