Re: [Netrexx-develop] interactive trace

[Marc R. <re...@gm...>]

I've updated branch interactive-trace.

You now have access to method variables and arguments, you can view or modify their values. Accessing properties still throws an exception.

On the interactive trace *-> prompt you can now:

   press [Enter] to trace interactively
   type '=' to reinterpret current clause
   type '-[n]' to show previous n clause(s), shows current clause if n is absent
   type '+[n]' to show next n clause(s), shows next clause if n is absent
   type 'trace off' to stop tracing
   any other clause entered must be either an assignment or a SAY instruction

I've turned away of touching existing code as much as possible, so albeit experimental, impact on existing code is limited to nonexistent.

A sample run :
<<
$ cat trace.nrx

class trace

   method main(args=String[]) static
     say 'interactively tracing..'
     trace int
     i=0
     say 'i='i
     do
       say 'Hello world'||'!'.copies(i)
     end
     trace off
     x=traces(9)
     say 'x:'x
     xx=traced(9)
     say 'xx.prop:'xx.prop
     loop while i < 5
       trace int
       i=i+1
       say 'i='i
       say 'Hello world'||'!'.copies(i)
     end

   method traces(arg=Rexx) static
     trace int
     say 'method traced called'
     say 'traced:'arg
     return arg

class traced
   properties public
   prop = 9

   method traced(arg=Rexx)
     trace int
     say 'prop:'prop
     say 'class traced constructed'
     say 'traced:'arg
      
$ nrc -exec trace
NetRexx portable processor 4.04-alpha build 1,558-20220616-1912
Copyright (c) RexxLA, 2011,2022.   All rights reserved.
Parts Copyright (c) IBM Corporation, 1995,2008.
Program trace.nrx
   === class trace ===
     function main(String[])
     function traces(Rexx)

   === class traced ===
     constructor traced(Rexx)
===== Exec: trace =====
interactively tracing..
     *->
     --- trace.nrx
   6 *=*     i=0
     >v> i "0"
     *-> say i
0
     *-> i=3
     *-> say i
3
     *->
   7 *=*     say 'i='i
     >>> "i=3"
i=3
     *->
   8 *=*     do
     *->
   9 *=*       say 'Hello world'||'!'.copies(i)
     >>> "3"
     >>> "Hello world!!!"
Hello world!!!
     *->
  10 *=*     end
     *->
  11 *=*     trace off
     *->
  25 *=*     say 'method traced called'
     >>> "method traced called"
method traced called
     *-> -3
method traces(arg=Rexx) static
trace int
say "method traced called"
     *-> say arg
9
     *-> arg=8
     *->
  26 *=*     say 'traced:'arg
     >>> "traced:8"
traced:8
     *->
  27 *=*     return arg
     >>> "8"
     *->
x:8
     *->
  35 *=*     say 'prop:'prop
     >>> "prop:9"
prop:9
     *->
  36 *=*     say 'class traced constructed'
     >>> "class traced constructed"
class traced constructed
     *-> -3
trace int
say "prop:"prop
say "class traced constructed"
     *-> -5
prop=9
method traced(arg=Rexx)
trace int
say "prop:"prop
say "class traced constructed"
     *-> say arg
9
     *-> arg=8
     *-> say arg
8
     *->
  37 *=*     say 'traced:'arg
     >>> "traced:8"
traced:8
     *->
xx.prop:9
     *->
  18 *=*       i=i+1
     >v> i "4"
     *->
  19 *=*       say 'i='i
     >>> "i=4"
i=4
     *-> trace off
Hello world!!!!
     *->
  18 *=*       i=i+1
     >v> i "5"
     *->
  19 *=*       say 'i='i
     >>> "i=5"
i=5
     *->
  20 *=*       say 'Hello world'||'!'.copies(i)
     >>> "5"
     >>> "Hello world!!!!!"
Hello world!!!!!
     *->
  16 *=*     loop while i < 5
     >>> "0"
     *->
  21 *=*     end
     *->
Processing of 'trace.nrx' complete [2 classes]
>> 

Please test;

Marc

On 6/7/22 13:42, Marc Remes wrote:
> I've submitted branch interactive-trace, an *experimental* *experiment* to mimic Classic Rexx interactive trace capabilities.
> 
> The new 'TRACE INT' instruction will intercept and pause execution during interpretation and present a '*->' prompt to the user.
> Pressing [Enter] will interpret next clause
> Typing '=' will reinterpret current clause
> Typing '?' will show usage
> Typing 'TRACE OFF' will stop interactive trace and will continue normally with next clause
> Typing anything else is currently 'not supported'.
> 
> TRACE INT is only active when interpreting NetRexx code, otherwise a warning 'TRACE INT ignored when compiling' is shown.
> 
> An example:
> <<
> $ cat trace.nrx
> 
> class trace
> 
>     method main(args=String[]) static
>       say 'interactively tracing..'
>       trace int
>       i=0
>       say 'i='i
>       do
>         say 'Hello world'||'!'.copies(i)
>       end
>       trace off
>       loop while i < 5
>         trace int
>         i=i+1
>         say 'i='i
>         say 'Hello world'||'!'.copies(i)
>       end
>>>
> 
> Sample run:
> <<
> $ nrc -exec trace
> NetRexx portable processor 4.04-alpha build 1,400-20220530-2046
> Copyright (c) RexxLA, 2011,2022.   All rights reserved.
> Parts Copyright (c) IBM Corporation, 1995,2008.
> Program trace.nrx
>     === class trace ===
>       function main(String[])
> ===== Exec: trace =====
> interactively tracing..
>    *->
>       --- trace.nrx
>     6 *=*     i=0
>       >v> i "0"
>    *->
>     7 *=*     say 'i='i
>       >>> "i=0"
> i=0
>    *-> trace off
> Hello world
>    *->
>    14 *=*       i=i+1
>       >v> i "1"
>    *-> trace off
> i=1
> Hello world!
>    *->
>    14 *=*       i=i+1
>       >v> i "2"
>    *-> =
>       *=*       i=i+1
>       >v> i "3"
>    *->
>    15 *=*       say 'i='i
>       >>> "i=3"
> i=3
>    *->
>    16 *=*       say 'Hello world'||'!'.copies(i)
>       >>> "3"
>       >>> "Hello world!!!"
> Hello world!!!
>    *->
>    12 *=*     loop while i < 5
>       >>> "1"
>    *-> trace off
>    *->
>    14 *=*       i=i+1
>       >v> i "4"
>    *-> trace off
> i=4
> Hello world!!!!
>    *-> trace off
> i=5
> Hello world!!!!!
> Processing of 'trace.nrx' complete
>>>
> 
> Do not reinterprete a clause that changes 'level' depth:
> <<
> $ nrc -exec trace
> NetRexx portable processor 4.04-alpha build 1,400-20220530-2046
> Copyright (c) RexxLA, 2011,2022.   All rights reserved.
> Parts Copyright (c) IBM Corporation, 1995,2008.
> Program trace.nrx
>     === class trace ===
>       function main(String[])
> ===== Exec: trace =====
> interactively tracing..
>    *->
>       --- trace.nrx
>     6 *=*     i=0
>       >v> i "0"
>    *->
>     7 *=*     say 'i='i
>       >>> "i=0"
> i=0
>    *->
>     8 *=*     do
>    *->
>     9 *=*       say 'Hello world'||'!'.copies(i)
>       >>> "0"
>       >>> "Hello world"
> Hello world
>    *->
>    10 *=*     end
>    *-> =
>       *=*     end
>    *-> =
>       *=*     end
> Exception in thread "main" java.lang.NullPointerException: Cannot read field "prev" because "<parameter1>.curlevel" is null
>      at org.netrexx.process.RxInterpreter.poplevel(RxInterpreter.java:1590)
>      at org.netrexx.process.NrEnd.interpret(NrEnd.java:174)
>      at org.netrexx.process.RxInterpreter.runfree(RxInterpreter.java:1314)
>      at org.netrexx.process.RxInterpreter.callMethod(RxInterpreter.java:1180)
>      at org.netrexx.process.RxInterpreter.callMethod(RxInterpreter.java:835)
>      at org.netrexx.process.RxTranslator.exec(RxTranslator.java:791)
>      at org.netrexx.process.NetRexxC.process(NetRexxC.java:536)
>      at org.netrexx.process.NetRexxC.main2(NetRexxC.java:345)
>      at org.netrexx.process.NetRexxC.main2(NetRexxC.java:324)
>      at org.netrexx.process.NetRexxC.main2(NetRexxC.java:320)
>      at org.netrexx.process.NetRexxC.main(NetRexxC.java:174)
>>>
> As such, the code is to be considered experimental..
> 
> Pressing [Enter] without interfering with execution should not have other impact than 'pausing' execution.
> 
> Obviously, 'not supported' should be replaced by interpreting the provided 'trace' clause in the context of the current program with access to the current varpool.
> Unfortunately, this is not trivial, at least with my understanding of Mike's code.
> 
> Marc
> 
> 
> 
> 
>