►
Description
Discussion for Chapter 5: Objects and Classes
A
A
B
A
A
I
have
been
I've
only
missed
two
chapters,
and
now,
okay,
I'm
blaming
the
holidays.
I've
been
watching
the
videos
asynchronously
okay,
when
you
ping
me
on
this
one,
I'm
I'm
glad
you
moved
it.
Although
it
turns
out
it
didn't
matter,
it
used
to
be
that
this
meeting
was
scheduled
when
my
kids
swim
team
practice
was
yeah
and
then
they
moved
that
so
it
no
longer.
A
B
B
B
B
B
B
Right
things
you
can
actually
like
use
in
your
day
to
day
that
you
could
be
like.
Oh,
this
is
actually
I
know.
If
I
add
you
know
the
eighth
instance
variable
whatever
it's
going
to
take
longer,
because
it
has
to
create,
where
allocate
more
memory
or
whatever,
not
that
anybody's
going
to
use
that.
But
it
relates
a
little
bit
more
closer
to
day-to-day
development.
B
So
something
I
actually
learned
that
I
didn't,
I
don't
think
I
ever
knew
before
at
least
I'd
never
had
tried
before
was
the
idea
of
a
class
instance
variable
where
you
could
just
just
say
at
you
know
whatever
equals
something
right
inside
a
class
like.
I
don't
think
I'd
ever
tried
that
before
I
just
assumed
it
would
not
work.
C
C
B
Yeah
because
I've
used
the
double
at
sign
like
for
the
class.
What
is
that
class
variable?
Not
the
class
instance
variable,
but
the
class
variable
I've
used
that
before,
but
I
recently
actually
had
need
of
a
class
instance
variable
type
structure,
and
I
think
we
ended
up
with
something
that
rails
has
included
in
it
like
class
attribute
or
something
like
that.
B
C
C
Just
like
the
way
the
classes
are
set
up,
it's
I
think
it's
called
the
composite
pattern.
If
I
remember
the
design
patterns
correctly,
which
just
like
you
know,
it's
the
same
template
again
and
again
and
again
on
top
of
each
other,
they
can
just
keep
stacking,
and
I
was
curious,
like
ruby
was
in
the
mid
90s
and
that's
also
when
the
design
patterns
book
came
out.
So
I
was
curious
if,
if
this
was
implemented
before
or
after
there
was
just
like
a
thought
out.
A
B
C
C
A
B
A
D
I
I
had
a
question
that
I
wasn't
sure
about
that
might
have
come
up
in
the
they
have
the
two
examples
of
a
an
r
object,
and
then
they
just
have
the
the
instance
variable
pointer
with
like
an
array
and
euler
has
two
names:
you've
got
leonardo
euler
and
then
euclid
you
slid.
How
do
you
say
that
I've
never
read
that
you
played,
I
think
yeah,
just
just
has
the
first
name.
D
B
Yeah
I
thought
that
was
kind
of
interesting
too,
like
there
was
a
couple
different,
conflicting
narratives
I
felt
like
I
was
receiving.
One
was
like
so
you
have
this
array
of,
of
instance,
variable
names
I
guess
or
attribute
names,
and
you
have
this
array
of
values,
and
I
was
like:
does
it
just
map
those
up
one
to
one
like
zip
them
together
and
the
other
one
was
that
there
was
like
a
hash
lookup
table
where
it
was
like?
B
This
is
my
you
know,
instance,
variable
name
now,
look
it
up
in
this
hash
lookup
table
to
find
the
actual
value,
and
maybe
that
was
just
for
the
class
ones,
but
I
was
like.
Why
would
they
do
it
differently?
I
don't
know
well
yeah,
so
your
question
is
like
if
first
name
comes
first
and
then
last
name
comes
second,
if
we
just
have
first,
I'm
sure
it's
the
first
object
in
the
array.
If
we
just
have
a
last
name,
is
it
still
the
first
object
or
is
it
the
second
one.
D
B
B
B
B
Question
I
thought
it
was
really
interesting
that
for
certain
values
like
integers
and
true,
false
and
stuff
it
doesn't,
it
doesn't
create
a
point
or
two
like
a
class
or
an
instance.
It
just
like
puts
the
value
in
that
pointer
and
then
gives
it
like
the
little
flag
that
says
kind
of
what
type
of
value
it
is.
B
I
was
curious
like
what
sort
of
advantage.
I
guess
that
gives
you,
because
I
feel,
like
you,
still
have
to
do
extra
like
logic,
to
figure
out
based
off
the
flag,
what
type
of
value
or
you're
dealing
with
in
that
point,
or
whether
it's
pointing
to
an
instance
or
whether
it's
you
know
a
what
is
it
a
primitive?
I
guess.
D
B
C
B
B
But
I
feel
like
yeah,
I'm
really
just
curious
how
that
works,
because
it
still
has
to
figure
out
the
class
of
whatever
that
value
is,
if
you
ask
for
it,
and
if
you
try
to
perform
methods
on
it,
it
still
probably
has
to
go
to
that
class
to
figure
out
what
those
methods
do.
So
I
feel
like
it
seems
to
save
a
marginal
amount
of
space
for
a
very,
like
small
amount
of
time
to
me,
but
maybe
that's
not
how
it.
A
B
B
B
B
What
its
purpose
is,
which
makes
a
lot
of
sense,
because
in
order
to
have
like
they
were
saying
in
order
to
have
class
methods,
those
methods
get
stored
in
the
instance
of
you
know
whatever
or
in
the
getting
all
confused
now
in
the
class,
I
guess
anyway,
you
couldn't
put
them
in
the
base
class,
because
then
every
class
would
have
them,
but
you
have
this
intermediate
class.
It
sits
between
it's
kind
of
hidden
that
you
can't
really
get
to,
but
it's
there
for
that
purpose.
C
A
A
C
C
B
C
B
B
B
But
your
class,
so
this
is
this-
is
something
that
I
don't
quite
understand.
So
this
must
be
just
a
very
special
construct,
because
if
you
ask
for
your
classes
class,
it's
always
going
to
be
the
class
class,
it's
not
going
to
be
your
eigen
class
class,
so
they
must
be
somehow
skipping
that,
for
that
particular
case,
which
seems
interesting.
B
So
like
in
here
he's
got
the
mathematician
class
that
he
makes
and
then,
if
you
say
mathematician
like
with
the
capital
m
dot
class,
it
will
always
report
class
with
a
capital
c.
But
that's
not
the
actual,
like
that's
not
what
it's
actually
like
an
instance
of,
because
it's
an
instance
of
that
meta
class.
That
singleton
class
is
actually
what
it's
an
instance
of.
B
D
C
C
B
C
A
B
D
B
So
then
we
could
say
that
there
is
this
sort
of
like
untouchable
base,
our
class
that
nothing
really
ever
inherits
from
directly.
Everything
always
has
something
that
sits
in
between
it,
it's
a
copy
of
it.
Basically,
I
don't
know
if
it's
a
copy
or
if
it's
a
pointer
to
it
and
a
similar
superclass
chain,
but
yeah.
That's
really
interesting.
B
D
C
C
Yeah,
I
think
one
of
the
other
things
that
I
just
like
thought
stood
out
as
being
kind
of
neat
was
the
instance.
Variables
are
just
saved
in
an
array,
just
the
values
of
them
so
like
because
they
go
into
that
whole
like
update
and
performance,
where
it
used
to
be
pretty
much
a
hash
of
the
name
and
value,
and
then
they
moved
the
names
to
the
class
and
then
all
the
objects
just
have
the
array.
I
thought
that
was
kind
of
like
that's.