HP TACL User Manual

Debugging TACL Programs
Developing TACL Programs
2–32 107365 Tandem Computers Incorporated
Debugging TACL
Programs
The TACL debugger shows how TACL interprets code. It provides step-by-step
execution, examination of control flow, and examination and modification of variables.
The debugger is a separate function, invoked by TACL upon request.
For information about how to debug #DELTA code, see “#DELTA Built-In Function”
in the TACL Reference Manual.
Enabling the TACL
Debugger
You can enable the debugger interactively or from within a macro or routine:
At a TACL prompt, after loading a macro or routine variable, but before invoking
it, type:
10> BREAK variable
From within a macro or routine, type the following to enable the debugger:
#SET #TRACE -1
When you enable the debugger, TACL waits for an instruction before it performs its
first expansion. At this point, you can set breakpoints and either resume execution or
step through the code.
Debugger Commands When tracing is on, the TACL trace facility invokes the _DEBUGGER function prior to
invoking a variable. The debugger displays the current history number:
- nnn -
At this point, you can enter a command. If you enter a TACL command, the debugger
passes the command to TACL for execution. If you enter a _DEBUGGER command,
_DEBUGGER executes the command. Table 2-5 lists _DEBUGGER commands.
Table 2-5. _DEBUGGER Command Syntax
Command Description
B[REAK] [variable] Sets a breakpoint on the specified variable or variable level. If you omit
variable, TACL lists all breakpoints. Whenever you invoke variable,
TACL stops executing the code and waits for input from your debugging
terminal.
C[LEAR] [variable | *] Clears the breakpoint for the specified variable or variable level. If you
specify an asterisk (*), TACL clears all breakpoints.
D[ISPLAY] variable Displays the contents of the specified variable or variable level.
M[ODIFY] variable Allows you to enter new contents for the specified variable or variable
level.
R[ESUME] Resumes execution until the next breakpoint or until TACL finishes
executing code.
ST[EP] Performs one expansion. To step through the function, press the
RETURN key after each subsequent prompt.

HP TACL Specifications

General

Brand	HP
Model	TACL
Category	Software
Language	English