TAL Reference Manual

TAL Reference Manual—526371-001
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1 Introduction
The Transaction Application Language (TAL) is a high-level, block-structured language
that works efficiently with the system hardware to provide optimal object program
performance.
The TAL compiler compiles TAL source programs into executable object programs.The
compiler and the object programs it generates execute under control of the NonStop
Kernel.
Applications and Uses
You use TAL most often for writing systems software or transaction-oriented
applications where optimal performance has high priority. You can, for example, use
TAL to write the kinds of software listed in Table 1-1.
Many NonStop software products are written in TAL.
Major Features
The major features of TAL are:
•
Procedures—Each program contains one or more procedures. A procedure is a
discrete sequence of declarations and statements that performs a specific task. A
procedure is callable from anywhere in the program. Each procedure executes in
its own environment and can contain local data that is not affected by the actions of
other procedures. When a procedure calls another procedure, the operating
system saves the caller’s environment and restores the environment when the
called procedure returns control to the caller.
Table 1-1. Uses of TAL
Kind of Software Examples
Systems Software Operating System Components
Compilers and Interpreters
Command Interpreters
Special Subsystems
Special routines that support data communication
activities
Applications Software Server processes used with NonStop data
management software
Conversion routines that allow data transfer between
NonStop software and other applications
Procedures that are callable from programs written in
other languages
Applications that require optimal performance