Break Point Command Line

When a breakpoint expires you will be left at a command prompt where you can type a number of specialised command or any rexx statement.

You can specify a command or commands to be automatically executed whenever a breakpoint expires by defining them via the REXX_BP_AUTO_CMD macro.

Simply enter the command and press "ENTER", the command lines supported are:

• Empty Command
  If you don't enter any command (that is simply press [enter]), ppwizard continues until the breakpoint expires again.

• ?
  In case you have forgotten the step you are up to or it scrolled off the screen then you can redisplay just the text of the message again (no variables are dumped).

• ?a[liases]
  This command shows you all aliases that you have created in the past. It will not show any aliases you defined using REXX_BP_ALIAS:? macros.

• ?#[aliases]
  All commands that you type in are automatically remembered. This command is used to list the commands, to reuse a remembered command you need to specify it by number (which changes as you enter new commands - but not as you use previous ones).

• ?v[ariables] [variable list]
  This works in two modes:

  • If a variable list is not supplied then the current rexx block is examined to locate variables and these are dumped. Note that this won't dump whole arrays, just variables that are easily recognisable by looking at the rexx code.

  • If a variable list is supplied then any that don't exist will be reported otherwise the values of the listed variables will be displayed.

    Note that the command "?v fred" is better than "say fred" as the output will go to any /ConsoleFile.

• ?l[ocation]
  This tells you if the current processing location (file and line number).

• ?m[acro] MacroNameParm
  This tells you if the specified macro exists and if so what its value is. The value is surrounded by double quotes so you can see where whitespace exists.

• /alias
  This executes a previously set up command (an alias). Its a shorthand way of specifying frequently used commands. If the alias is numeric or begins with '#' then this is referring to an automatic alias and not one that you created.

  Note that you can also use aliases you defined as macros, these have precedence.

• /alias=value
  This allows you to specify a command. Do not use an alias that begins with '#' or is numeric. The alias may or may not be remembered depending on how REXX_BP_ALIAS_FILES is setup.

• BP
  This will prompt you for a new breakpoint. Type "" for none. See the "REXX_BP" documentation for details about valid values. Note that brealpoints set this way only last until the current block of rexx code terminates.

• None of the Above
  You have supplied a rexx command which will be executed. If the command is "exit" then ppwizard will terminate! PPWIZARD protects you from syntax errors in this prompt.

  You could use this prompt to "say" the values of rexx variables or anything else you require (run programs or anything else you can normally do in a rexx program).

Example of use is:

;--- Define some code that can be called to detect a breakpoint -------
#DefineRexx TestBreakpointCode TRACE_OFF
            ;--- Simple test (same as simpler REXX_BP value) ----------
            if pos('{SOL}x = 2{EOL}', RtSearchText) <> 0 then
               rtStop = 'Y';               ;;Want debug prompt!

            ;--- Also stop if variable 'FRED' exists and equals '1' ---
            if symbol('FRED') = 'VAR' then
            do
               if  Fred = 1 then
                   rtStop = 'Y';           ;;Want debug prompt!
            end;
#DefineRexx


;--- Other possible settings for below --------------------------------------
;#define REXX_BP          {SOL}x = 2{EOL}          ;;Set break point for when x = 2 (whole line ie not "x=22" etc)
;#define REXX_BP          =TestBreakpointCode      ;;Stop where my code says
;#define REXX_BP_ALIAS:B  say 'Dennis was here (alias B)'
;#define REXX_BP_ALIAS_FILES  ;project.a;global.a  ;;Define alias files used (changes NOT saved)

;--- Define rexx code to be debugged (Execute it) ---------------------
#define RexxTrace           OFF                  ;;Don't want to see interpreters output
#define REXX_BP             ?                    ;;Stop anywhere (first $trace)
#define REXX_BP_ALIAS_FILES project.a;global.a   ;;Define alias files used (changes saved to "project.a")
#DefineRexx ''
   Fred = 1;
   do x = 1 to 3
      $trace                  ;;trace next command
      y = x; fred2 = Fred;
   end;

   ;--- Dump all vars now ---
   $trace Finished, dumping all vars
#DefineRexx

Some sample output (without breakpoint output):

---------- REXX TRACE - START(OFF) ----------
$TRACE: @4 -> y = x; fred2 = Fred
      |    x = 1
      | Fred = 1
$TRACE: @4 -> y = x; fred2 = Fred
      |     y = 1
      |     x = 2
      | fred2 = 1
      |  Fred = 1
$TRACE: @4 -> y = x; fred2 = Fred
      |     y = 2
      |     x = 3
      | fred2 = 1
      |  Fred = 1
  $SAY: Finished,dumping all vars
      |  Fred = 1
      |     x = 4
      |     y = 3
      | fred2 = 1
---------- REXX TRACE - END(OFF) ----------

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PPWIZARD Manual

Saturday May 28 2022 at 2:55pm