Re: [Netrexx-develop] interactive trace

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

Latest push fixes access to properties

On 6/17/22 10:49, Marc Remes wrote:
> 
> 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
>>
>>
>>
>>
>>