I've seen your posts from (what are we gonna call it?) output in perl -de0 mode for years now, and they've mostly been over my head. Only recently have I discovered that I have a REPL too. I could have replicated your REPL.

Can you elaborate?

I would extend that to foreign code in general. I can't understand and integrate others' code into mine without it, whilst working alone. The number of keystrokes I save using the debugger is immeasurable. With successive use of save/source, it's like a trail in the forest and can even tell a story, and it's one you keep telling until you get out of the forest. I worked a little harder on a modifed script from bliako, and I'm able to point out places in code as perl -de0 sees it, and I can get into the nitty-gritty of execution. I'll repost the 2020 perl -de0 demonstration by Ricardo Signes, for reference. I place sources and debugger output in readmore tags:

Q1) What makes my Log4perl section a signature? This version is from parv, and I like that it gives me line numbers, but I don't see code for that. (?)

Q2) How would I turn the above script into "monolithic" foreign code?

Q3) Does Data::Roundtrip cover the same ground that JSON::XS did? I can't disambiguate what XS means.

Q4) What operator is this? I believe it takes my global value of 1 for $debug and makes it zero:

Q5) Finally, reading all around these issues, I found this one-liner and was wondering if this would fall under the umbrella of what "the debugger" might be. What is happening with this command?

$ perl -Mre=debug -e "/just|another|perl|hacker/"
Compiling REx "just|another|perl|hacker"
~ tying lastbr BRANCH (11) to ender END (15) offset 4
Final program:
   1: TRIEC-EXACT[ahjp] (15)
      <just> 
      <another> 
      <perl> 
      <hacker> 
  15: END (0)
stclass AHOCORASICKC-EXACT[ahjp] minlen 4 
Freeing REx: "just|another|perl|hacker"
$
[download]

Thx for your comment

Q4) What operator is this? I believe it takes my global value of 1 for $debug and makes it zero

It is the defined-or-equals operator. It assigns the RHS to the LHS only if the LHS is undefined. It is listed in perlop along with all the other operators.

---

🦛

It is the defined-or-equals operator. It assigns the RHS to the LHS only if the LHS is undefined. It is listed in perlop along with all the other operators.

Thanks, I was reading it wrong. I wouldn't say the documentation is particularly thick about it:

$ perldoc perlop | grep '//='
               .=    %=    ^=    ^.=           //=
$
[download]

, but I see why bliako uses it, and think I'll borrow the scheme.

Q3) Does Data::Roundtrip cover the same ground that JSON::XS did? I can't disambiguate what XS means.

Data::Roundtrip requires the JSON distribution. When used, the JSON module will load JSON::XS if it is available to your interpreter, and the pure perl JSON::PP if not. JSON::PP has been in core since ~5.14, so this functionality is very handy instead of just having your script fall over if JSON::XS isn't installed.

XS simply means that there are components to the software that are compiled, therefore in most cases making much of its functionality much, much faster.

One of my distributions, Bit::Manip is an XS based module, but I also have a pure perl version (Bit::Manip::PP) for those who can't or don't want to compile software. Here's a benchmark script between the two, and the results. The C/XS version is ~394% faster than the pure perl version:

use warnings;
use strict;
 
# performs a benchmark between this XS 
# version and the PP version
 
use Benchmark qw(timethese cmpthese);
use Bit::Manip;
use Bit::Manip::PP;
 
my $do = $ARGV[0];
 
timethese(1000000, {
        'c' => 'c',
        'p' => 'p',
    }
);
 
cmpthese(1000000, {
        'c' => 'c',
        'p' => 'p',
    }
);
 
sub c {
    Bit::Manip::bit_set(65535, 0, 8, 0xFF);
}
sub p {
    Bit::Manip::PP::bit_set(65535, 0, 8, 0xFF);
}
 
__END__
 
Benchmark: timing 1000000 iterations of c, p...
         c:  3 wallclock secs ( 3.35 usr +  0.00 sys =  3.35 CPU) @ 29
+8507.46/s (n=1000000)
         p: 17 wallclock secs (16.58 usr +  0.00 sys = 16.58 CPU) @ 60
+313.63/s (n=1000000)

      Rate    p    c
p  60606/s   -- -80%
c 299401/s 394%   --
[download]

One of my distributions, Bit::Manip is an XS based module, but I also have a pure perl version (Bit::Manip::PP)

I'm intrigued why you called one Bit::Manip::PP but didn't name the other Bit::Manip::XS. Intrigued because naming of modules seems a bit of a dark art to me despite all the advice on the matter.

Aldebaran++ that's really cool addition you got there!

Q2) How would I turn the above script into "monolithic" foreign code?

Turn your additions into a sub (a subroutine aka function) which will be a complete black box. It will take some inputs, and return some outputs (print if you must but don't forget to return all you need to return to the caller so that your sub is useful). For example:

sub func {
my ($event, @planet_names) = @_; # read in parameters supplied by call
+er as in func($xyz)
# check that we have some names and that event contains the fields we 
+need
# return undef on error.
# caller must check if received undef!
return undef unless @planet_names;
return undef unless exists $event->{epoch};
...
my %returned_planets = ();
for my $a_planet_name (@planet_names){
my $planet = Astro::Coords->new( planet => $name );
...
$returned_planets{$a_planet_name} = $planet;
}
# return to the caller results as a hashref
# I always use refs for params and results. others may not.
return \%returned_planets;
} # end of my function

# example use
my $ret = func($anevent, "venus", "saturn");
die "func() failed" unless defined $ret;
# and now do what you like with the results.
[download]

I am referring to the code you presented above about here:

for my $event (@events) {
  my $epoch = parse_event($event);

  my ( $MoonPhase, $MoonIllum, $MoonAge, $MoonDist, $MoonAng, $SunDist
+,
    $SunAng ) = phase($epoch);
[download]

Then build some test cases to test your sub. Edge cases (e.g. empty planet names, wrong names) and also cases you know the result. And you are good to go :)

Todo: at this stage it is a prototype. When final, we can turn this into OO, with $event being a class. But that's much later.

Let me know how you convert your additions into a sub.

Q3) Does Data::Roundtrip cover the same ground that JSON::XS did? I can't disambiguate what XS means.

It's just a wrapper around many great modules to implement things like json2perl, perl2yaml with (hopefully correct) unicode suppprt. Don't worry about it. But you can safely replace it with calls to JSON's decode() etc. (which, as stevieb said, switches between XS or PP depending what is installed on your system) so that you have one less dependency.

BTW, I think you also provided me with an answer as to why I never use the debugger :)

bw, bliako

Let me know how you convert your additions into a sub.

I'll work on that. I appreciate the concrete Anweisungen

It's just a wrapper around many great modules to implement things like json2perl, perl2yaml with (hopefully correct) unicode suppprt. Don't worry about it. But you can safely replace it with calls to JSON's decode() etc. (which, as stevieb said, switches between XS or PP depending what is installed on your system) so that you have one less dependency.

Ok, it helps to know that PP is the alternative, and PP stands for, wait for it, pure perl.

BTW, I think you also provided me with an answer as to why I never use the debugger :)

I'm happy to provide you with certainty, a rare commodity in this world. :) Like I say, for me it's usually when I'm hooking up parts that are new to me, and I have to figure out what is not happening with values. With hippo's help, I've figured out parts of your debugging scheme, and see how it's built. I wasn't calling it correctly.

>> p @_
43.61-116.20
>> p $debug
0
[download]

I had been passing a bare zero (a hasty stubout) as the third argument to this routine. this was undefined on arrival. Now I have improved it to hook into your debugging scheme, as you define $debug in the caller:

  my $return = get_elevation_from_coordinates( $event->{location}->{la
+t},
    $event->{location}->{lon}, $debug );
[download]

Then I get the internals of the exchange with google, and everything makes even more sense:

./6.mp.pl : latitude=-15.6325&longitude=-141&application_max_assets_mt
+ime=1559625591
./6.mp.pl : sending above payload, of 72 bytes...
INFO: return from the google is 0 meters
[download]

When I hit M in the debugger too see what version of JSON I was running, I was surprised to see that

/usr/local/lib/x86_64-linux-gnu/perl/5.30.0/JSON/XS.pm

was among the loaded modules. I take that to mean that perl is covering its bases for backwards compatibility. I wonder how I might determine whether execution ran through it(?) What's more, I found my PP.pm module, and read it mod 1:

locate  *JSON/PP.pm

, wherein is:

     # Note that JSON version 2.0 and above will automatically use
     # JSON::XS or JSON::PP, so you should be able to just:
 
     use JSON;
[download]

Again, with the M command, I see that my version is way north of 2.0:

'JSON.pm' => '4.03 from /usr/local/share/perl/5.30.0/JSON.pm'
'JSON/XS.pm' => '4.03 from /usr/local/lib/x86_64-linux-gnu/perl/5.30.0
+/JSON/XS.pm'
[download]

So, after all this, I see that it is not of any practical concern for what I do with json. What's more, I would be hesitant to fire a cannon of requests in compiled c to the same server. It might exceed what many consider polite. Love them or hate them, I don't want to be on the wrong side of the google.

Now perl -de0 is commonly known as "The Debugger" , which is causing reactions.
Unfortunately "people with strong opinions" here have a Pavlov reflex to demonstrate their ignorance.

My personal Pavlov reflex kicks in when someone tries to save his own efforts on the cost of others. Primarily with highly misspelled or misformatted text targeted to a larger audience.

But almost equally this is the case with examples given here that require an unnecessary effort to reproduce. This includes "debugger sessions". The simplest modifiable thing to reproduce is a runnable perl script. Anything else I regard as laziness.

> Anything else I regard as laziness.

Well I've probably produced 100 times more code for this board than you, and you - whoever you think you are - call me lazy.

> given here ...

Seems like you can't even link properly

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}