Debugging with GT.M

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Simple 'IDE' with GT.M
This is a simple debugger created with GT.M debugging commands:

It will currently show the source code, with the current line highlighted, as it steps through the code.

Here are the modules TMGIDE.m TMGTERM.m TMGTPSTP.m

'''NOTE: These modules have been greatly modified since first posted. The latest versions can be found in the TMG code library, which can be downloaded here. Look for VistAMisc_TMG-library_Kevin_ '''

To invoke: do ^TMGIDE

K. Toppenberg

GT.M Debugging commands
This information is from the GT.M Programmer's Manual. I'll just summarize a few points.


 * Dumping Information (actually just writes it out) when an error occurs.
 * ZSHOW argument
 * ZSHOW "*" dumps all info known
 * ZSHOW "S" dumps the current stack
 * ZSHOW "B" dumps the current breakpoints established with ZBREAK command (below)

This is a list of past errors, separated by commas. Subsequent errors are added to the end of the list. Example: GTM>w $ECODE ,M6,Z150373850, Errors beginning with: "M" are standard errors "U" are user errors "Z" are GT.M errors
 * $ECODE

This is detail about the most recent error. Example: GTM>w $ZSTATUS 150373850,SubName+3^MyFunct,%GTM-E-UNDEF, Undefined local variable: Jxack
 * $ZSTATUS

This will give a text message for a given error number. Example: To get details about the error number, 150373850, given above... GTM>w $ZMESSAGE(150373850) %GTM-E-UNDEF, Undefined local variable: !AD
 * $ZMESSAGE(x)

This will display the line that cause the program exception. The 'x' may be obtained from $ZSTATUS, or from $ZPOS (see below)
 * ZPRINT x (e.g. ZPRINT SubName+3^MyFunct)

Shows the current position of the current line of execution (or the last line exececuted in case of an error) From the manual: $ZPOSITION is a read-only GT.M special variable that provides another tool for locating and displaying the current line. It contains the current entry reference as a  character string in the format label+offset^routine, where the label is the closest preceding label. The current entry reference appears at the top of the M invocation stack, that can also be displayed with a ZSHOW “S” command. Example: GTM>W $ZPOS name+2^dmex This example writes the current line position.
 * $ZPOSITION (OR $ZPOS)

Shows the entire variable table, displaying all defined variables.
 * ZWRITE

Toggles a break point at address. If CodeToExecute is null, then a    default value of break is used (dropping one back to the command line.) If CodeToExecute does not contain break, zbreak (or is not null) then control will not be dropped to the command line GTM>
 * ZBREAK address:CodeToExecute

I believe that GT.M maintains only ONE breakpoint. e.g. GTM>ZBREAK Label+1^MyFunct:"set x=1"

Will execute the program one line at a time. I think this would be typically used after a ZBREAK drops command back to GT.M> Prompt. ZSTEP INTO -- start execution at current execution point, and stops at                   next line (even if that line is in a subroutine). ZSTEP [OVER] -- start execution at current exec. point, and stop at the next line at the same level on the invocation stack. ZSTEP OUTOF -- ??
 * ZSTEP x

Continue execution from break point.
 * ZCONTINUE

$STACK starts at 0 and each DO inc's the value, each QUIT dec's it   $ZLEVEL is $STACK+1
 * $STACK AND $ZLEVEL

.. More later