TAL Programmer's Guide

Using Compiler Directives
Structuring Programs
3–18 096254 Tandem Computers Incorporated
Null Statements
You can use a semicolon without a statement to create a null statement, which means
do nothing. The compiler generates no code for null statements. You can use a null
statement anywhere you can use a statement, except immediately before an ELSE or
UNTIL keyword.
Here is an example of a null statement embedded in a labeled CASE statement:
CASE var OF
BEGIN
0 ->
; !Null statement
1 ->
CALL fixit; !CALL statement
END;
Using Compiler
Directives
Compiler directives are options provided by the TAL compiler so you can control the
compilation. For example, compiler directives let you:
Specify files from which to read in source code
Specify the content of compiler listings and object files
Conditionally compile portions of source code
You can specify most compiler directives either in the compilation command (that
runs the compiler) or in your source code.
In the compilation command, you can specify directives following the semicolon. For
example, to compile the source file MYSRC, send the object code to object file MYOBJ,
and specify the NOLIST directive to suppress the compiler listing, issue the following
command at the TACL prompt:
TAL /IN mysrc/ myobj; NOLIST
In your source file, you specify directives in directive lines. Start each directive line
with a question mark (?) in column 1 as follows:
?LIST
!Some code here
?NOLIST, NOCODE, INSPECT, SYMBOLS, NOMAP, NOLMAP, GMAP
?CROSSREF, INNERLIST
The following directive line has a continuation line for the argument list of the
SEARCH directive:
?SEARCH (file1, file2, file3, file4,
? file5, file6)