Exiting From Programs; Processing Character Data - HP TACL Programming Manual

Exiting From Programs

Processing Character
Data
The #FRAME built-in function creates a local environment for variables. The
#UNFRAME command restores variables to the state they were in at the time of the
last #FRAME operation. For more information about frames, see the TACL Reference
Manual.
TACL exits from a macro or text variable as soon as it encounters either of the
following conditions:
Successful completion of the code; TACL executes each line and exits when
finished.
Detection of an error condition, in which case TACL restores all variables to the
state they were in when the variable was invoked and then exits the variable.
If you use routine variables, you can use the #RETURN built-in function to return
conditionally from one or more locations in your code. For more information, see
"Returning Results" in Section 3, "Developing TACL Routines."
When writing a TACL program, you might need to examine or modify the contents of
variables. Such tasks include:
Constructing text strings for input to processes, files, or devices
Analyzing process output
Analyzing results of functions
For example, whenever you use RUN or #NEWPROCESS to initiate a process from
TACL, you can direct output from the process to a variable:
The OUT option directs program output to a file.
The OUTV option stores program output into a variable for later use.
Section 5, "Initiating and Communicating With Processes," describes process
initiation.
TACL supports several commands and functions that manipulate characters and lines
of characters within variables:
Commands, typically used for interactive work, perform editing operations on one
or more lines in a variable.
Built-in functions perform a single operation, referencing text by character
position or line number.
#DELTA, the low-level character editor, provides text editing capabilities similar to
those provided by the character and line oriented built-in functions. #DELTA is
complex; the newer #CHARxxx and #LINExxx built-in functions are easier to use.
STRUCT variables, or structures, allow you to define a set of elements and access the
elements by name. STRUCT variables support a range of data types. Structures are
helpful when communicating with processes such as $CMON, and are required when
communicating with the Subsystem Programmatic Interface (SPI) and the Event
Management Service (EMS).
107365 Tandem Computers Incorporated
Developing TACL Programs

Processing Character Data

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