Note: If you're unsure what a reference is, better check perlreftut and perlref. This node is not about Perl syntax or internals; it is about the English-ish jargon used to discuss references and related concepts.

Given:

use Devel::Peek;
use Perl6::Form;

my $dog;
my $cat;
my $bob;
my $sue;

{
    my $pest    = 'flea';
       $dog     = \$pest;
       $cat     = \$pest;
       $bob     = \$dog;
       $sue     = \$cat;
}

###
say q{};

say     'Dump $dog:';
         Dump $dog;
say q{};

say     'Dump $cat:';
         Dump $cat;
say q{};

say     'Dump $bob:';
         Dump $bob;
say q{};

say     'Dump $sue:';
         Dump $sue;
say q{};

###
say q{};

say  q*|      $                     $$                      $$$       
+     |*;
say  q*|--------------------------------------------------------------
+-----|*;
print form
    qq*|dog   {<<<<<<<<<<<<<<<}     {<<<<<<<<<<<<<<<}                 
+     |*,
            $dog,                   $$dog,
    qq*|cat   {<<<<<<<<<<<<<<<}     {<<<<<<<<<<<<<<<}                 
+     |*,
            $cat,                   $$cat,
    qq*|bob   {<<<<<<<<<<<<<<<}     {<<<<<<<<<<<<<<<}       {<<<<<<<<<
+<<<} |*,
            $bob,                   $$bob,                  $$$bob,
    qq*|sue   {<<<<<<<<<<<<<<<}     {<<<<<<<<<<<<<<<}       {<<<<<<<<<
+<<<} |*,
            $sue,                   $$sue,                  $$$sue,
    ;
## end form
say  q*|--------------------------------------------------------------
+-----|*;
say q{};

###
my $t       = 'A';

print   qq*|$t|  *;
            $t++;
say     q*   $dog eq   $cat: *, 
             $dog eq   $cat;

print   qq*|$t|  *;
            $t++;
say     q*  $$dog eq  $$cat: *, 
            $$dog eq  $$cat;

print   qq*|$t|  *;
            $t++;
say     q*   $bob eq   $sue: *, 
             $bob eq   $sue;

print   qq*|$t|  *;
            $t++;
say     q*  $$bob eq  $$sue: *, 
            $$bob eq  $$sue;

print   qq*|$t|  *;
            $t++;
say     q* $$$bob eq $$$sue: *, 
           $$$bob eq $$$sue;

#say   $pest;

say q{};

__END__

Output: 

Dump $dog:
SV = RV(0xa080f4c) at 0xa080f40
  REFCNT = 2
  FLAGS = (PADMY,ROK)
  RV = 0xa216eb8
  SV = PV(0x9fbb6d8) at 0xa216eb8
    REFCNT = 2
    FLAGS = (PADMY,POK,pPOK)
    PV = 0xa21cff0 "flea"\0
    CUR = 4
    LEN = 8

Dump $cat:
SV = RV(0xa08148c) at 0xa081480
  REFCNT = 2
  FLAGS = (PADMY,ROK)
  RV = 0xa216eb8
  SV = PV(0x9fbb6d8) at 0xa216eb8
    REFCNT = 2
    FLAGS = (PADMY,POK,pPOK)
    PV = 0xa21cff0 "flea"\0
    CUR = 4
    LEN = 8

Dump $bob:
SV = RV(0x9fdd9a4) at 0x9fdd998
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  RV = 0xa080f40
  SV = RV(0xa080f4c) at 0xa080f40
    REFCNT = 2
    FLAGS = (PADMY,ROK)
    RV = 0xa216eb8
    SV = PV(0x9fbb6d8) at 0xa216eb8
      REFCNT = 2
      FLAGS = (PADMY,POK,pPOK)
      PV = 0xa21cff0 "flea"\0
      CUR = 4
      LEN = 8

Dump $sue:
SV = RV(0x9fdd8f4) at 0x9fdd8e8
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  RV = 0xa081480
  SV = RV(0xa08148c) at 0xa081480
    REFCNT = 2
    FLAGS = (PADMY,ROK)
    RV = 0xa216eb8
    SV = PV(0x9fbb6d8) at 0xa216eb8
      REFCNT = 2
      FLAGS = (PADMY,POK,pPOK)
      PV = 0xa21cff0 "flea"\0
      CUR = 4
      LEN = 8


|      $                     $$                      $$$            |
|-------------------------------------------------------------------|
|dog   SCALAR(0xa216eb8)     flea                                   |
|cat   SCALAR(0xa216eb8)     flea                                   |
|bob   REF(0xa080f40)        SCALAR(0xa216eb8)       flea           |
|sue   REF(0xa081480)        SCALAR(0xa216eb8)       flea           |
|-------------------------------------------------------------------|

|A|     $dog eq   $cat: 1
|B|    $$dog eq  $$cat: 1
|C|     $bob eq   $sue: 
|D|    $$bob eq  $$sue: 1
|E|   $$$bob eq $$$sue: 1
[download]

Uncommenting the line say $pest; raises a compile-time strict exception, of course; that package $pest is not my $pest. I do this only to make clear that I'm not concerned about this in the least. I don't care what is or is not in scope; only what to call stuff when speaking English to you (for some value of 'English').

This is a fill-in-the-blanks question. Please choose words you want to use to talk about the things in the blanks.

• $pest ___(1)___ 'flea'
• $dog is a reference to $pest
• $dog ___(2)___ 'flea'
• $bob is a reference to $dog
• $bob is a ___(3)___ to $pest
• $bob ___(4)___ 'flea'
• 'flea' is the value of the variable $pest
• $pest is the ___(5)___ of $dog
• 'flea' is the ___(6)___ of $dog
• $dog is the ___(7)___ of $bob
• $pest is the ___(8)___ of $bob
• 'flea' is the ___(9)___ of $bob
• 'flea' is the ___(10)___ of $dog
• $dog and $cat are ___(11)___ {~similarity}
• $bob and $sue are ___(12)___ {~similarity}

Please be kind enough to number your picks according to the numbered blanks. It's okay to use the same word to fill in more than one blank if you consider the relationships expressed equivalent. You don't need to fill in all of the blanks for your reply to be useful. Thank you.

Summary:

1. holds,
   has the value,
   contains,
   has,
   is,
   
2. points to [something] that points to,
   is a reference to a reference to,
   
3. reference to a reference,
   pointer to a reference,
   pointer to a pointer,
   indirect reference,
   
4. points to a reference to a reference to,
   is a reference to a reference to a reference to,
   refers to a reference to [a reference to],
   
5. RV,
   address,
   referent,
   
6. referent of the referent,
   indirect referent,
   
7. value of the referent,
   
8. value of the referent of the referent,
   
9. equal,
   both references to [something],
   
10. both references to references to [something],
    [both] indirect references to [something],
    

---

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