LanX has asked for the wisdom of the Perl Monks concerning the following question:

Please compare these outputs of B::Deparse and B::Concise °

C:\>perl -MO=Deparse -e "my DB $x; print $x"
my DB $x;                                       # <-- DB
print $x;
-e syntax OK

C:\>perl -MO=Concise -e "my DB $x; print $x"
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
3     <0> padsv[$x:1,2] vM/LVINTRO ->4          # <-- no DB
4     <;> nextstate(main 2 -e:1) v:{ ->5
7     <@> print vK ->8
5        <0> pushmark s ->6
6        <0> padsv[$x:1,2] s ->7
-e syntax OK

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So where is the information hidden in the OP-tree, such that Deparse can see it but not Concise?

Please enlighten me! :)

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

°) for simplicity I just randomly picked a predefined package DB (debugger) as a dummy type.

update

Devel::Peek neither helps 

C:\>perl -MDevel::Peek -e "my DB $x=10; Dump $x"
SV = IV(0xee96a8) at 0xee96b8
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 10

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Replies are listed 'Best First'.
Re: Introspecting type informations?
by choroba (Cardinal) on Aug 03, 2019 at 20:53 UTC
    There's no difference if you omit the type: 
    diff <(perl -MO=Concise -e 'my DB $x; print $x') \
     <(perl -MO=Concise -e 'my    $x; print $x')

    [download]
    map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]
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[d/l]
[select]
      Exactly, so where is the information?
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Re: Introspecting type informations?
by Don Coyote (Hermit) on Aug 04, 2019 at 12:03 UTC

    Hi LanX.

    I tried just adding -wMstrict and the DB line no longer continued to show when being deparsed.

    As you had not mentioned this in the OP I think that would be the first thing to consider.

    C:\Users\deutoronomy>perl -wMstrict -MO=Deparse -e "my DB $x"
BEGIN { $^W = 1; }
use strict 'refs';
my $x;                    #<-- no DB
-e syntax OK

    [download]

    Could Concise be introducing strict compliance at some point?

[reply]
[d/l]
[select]
      Unlikely, I'd rather say your system is buggy. 
      $ perl -wMstrict -MO=Deparse -e 'my DB $x'
BEGIN { $^W = 1; }
use strict;
my DB $x;
-e syntax OK
$

      [download]

      Thanks for the interesting observation! :)

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

      update

      couldn't reproduce on win 

      C:\>perl -wMstrict -MO=Deparse -e "my DB $x"
BEGIN { $^W = 1; }
use strict;
my DB $x;
-e syntax OK

      [download]
[reply]
[d/l]
[select]
Re: Introspecting type informations? HvNAME(SvSTASH(SvRV(ST(0))))
by Anonymous Monk on Aug 04, 2019 at 07:35 UTC
    HvNAME(SvSTASH(SvRV(ST(0))))

    B:: does have SvSTASH

    I tried with Inline::C but it keeps crashing with "my TYPE ... " but plain scalar returns "(null)"

[reply]
      Thanks, probably you forgot to define TYPE.

      FYI you don't need inline C, B::Deparse is written in Perl and accessing all methods via the B:: backend.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]
        Heh. Didnt forget diagnostics always reminds. Show the B code then.
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Re: Introspecting type informations?
by Anonymous Monk on Aug 04, 2019 at 05:08 UTC

    Its where it belongs? 

    $ perl -MO=Concise -e "my DouBloon $x; print $x"
No such class DouBloon at -e line 1, near "my DouBloon"
-e had compilation errors.
8  <@> leave[1 ref] KP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) :{ ->3
-     <1> ex-rv2sv K/1 ->4
3        <#> gvsv[*x] ->4
4     <;> nextstate(main 1 -e:1) :{ ->5
7     <@> print K ->8
5        <0> pushmark ->6
-        <1> ex-rv2sv K/1 ->7
6           <#> gvsv[*x] ->7

$ perl -MO=Concise,-src -e "my DouBloon $x; print $x"
No such class DouBloon at -e line 1, near "my DouBloon"
-e had compilation errors.
8  <@> leave[1 ref] KP/REFC ->(end)
1     <0> enter ->2
# 1: -src not supported for -e
2     <;> nextstate(main 1 -e:1) :{ ->3
-     <1> ex-rv2sv K/1 ->4
3        <#> gvsv[*x] ->4
# 1: -src not supported for -e
4     <;> nextstate(main 1 -e:1) :{ ->5
7     <@> print K ->8
5        <0> pushmark ->6
-        <1> ex-rv2sv K/1 ->7
6           <#> gvsv[*x] ->7

    [download]
[reply]
[d/l]
      As already mentioned, the type must be an already defined package. Hence your compilation errors.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]
        Heh. Its not an opcode. The warning is parse/toke. Dont expect concise to talk about it.
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