2 Developing TACL Programs
107365 Tandem Computers Incorporated
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This section describes topics that are common to all types of procedural variables.
Topics include:
Defining program structure
Processing character data
Accessing time information
Accessing terminals
Debugging TACL programs
The TACL Reference Manual contains information about TACL statements, programs,
and the TACL environment. This information is prerequisite to the topics in this and
later sections.
Choosing a Type of
Variable
The choice of a type of procedural variable depends on the type of work you plan to
do. The variable types can be summarized as follows:
A macro is typically used for programs that have limited need for validation of
arguments and no need for conditional exits. Within a macro, you can:
Define and access data structures such as text and STRUCT variables.
Compare, move, and manipulate the contents of variables.
Process arguments.
Use TACL built-in functions and commands, including built-in functions that
provide conditional execution of code.
Use TACL built-in variables to specify or obtain information about the TACL
environment.
A routine is the most general and fully functioned type of procedural variable, and
is required for programs that handle exceptions (unusual events) or perform
complex flow of control operations. If you plan to perform complex argument
processing, a routine is recommended.
Routines provide all of the capabilities that are available from macros, plus they
support built-in functions such as #ARGUMENT and #RETURN that are not
available to macros. While routines can provide more functionality than macros,
they also require more knowledge.
This section contains examples that illustrate the use of macros; except where noted,
these techniques also apply to routines.
Section 3, “Developing TACL Routines,” discusses additional features that apply only
to TACL routines.