C.1.3.2 Placeholder and Design Comment Processing
While all languages with Version 3.0 of LSE support pro-
vide placeholder processing, each language defines specific
contexts in which placeholders can be accepted as valid pro-
gram code. The following list contains valid contexts in which
placeholder processing is allowed:
.
User identifiers in EXTERNAL statements
.
Names of RECORD types
.
Data types of a FUNCTION in a FUNCTION declara-
tion
.
Data types in a DECLARE statement
.
Entire statements
.
Comments
BASIC accepts optional LSE placeholders in any context
where optional syntax is allowed. Example C-1 shows several
contexts in which LSE placeholders and design comments
might appear in the design of a BASIC program.
BASIC support for placeholder and design comment process-
ing includes the following language-specific stipulations:
.
Pseudocode placeholders are designated with double
right- and left-angle brackets, << >> or « ».
.
Comment processing is limited to the header and declar-
ative sections of each compilation unit.
Placeholders can be either required or optional. Required
placeholders, which are delimited by braces ({}), represent
places in the source code where you must provide program
text. Optional placeholders, which are delimited by brackets
([ ]), represent places in the source code where you can either
provide additional constructs or delete the placeholder.
Additionally, when you use BASIC with LSE, the expanded
code might include ellispes (...) or vertical bars ( | ). Syntax
constructs followed by ellipses indicate that the constructs can
be repeated. A vertical bar between constructs indicates that
you must choose one of the constructs.
Table C-1 lists the three types of LSE placeholders.