0:00:25.560,0:00:27.980
All right, good morning people.

0:00:27.980,0:00:32.520
After a bright talk this morning by Ajey,[br]it's

0:00:32.520,0:00:37.930
time to get dark and dirty, OK. So I'm

0:00:37.930,0:00:42.190
from Josh Software, and it started in 2007.[br]These

0:00:42.190,0:00:47.100
are my Twitter handles. And I'm also an author.

0:00:47.100,0:00:50.040
I have a couple of books which are out.

0:00:50.040,0:00:53.720
Well it doesn't look so dark anymore, does[br]it?

0:00:53.720,0:00:57.750
So what is my talk gonna be about? Don't

0:00:57.750,0:01:01.610
worry. It's not gonna be anything scary. I[br]love

0:01:01.610,0:01:06.570
Ruby. But as with every marriage, and I hope

0:01:06.570,0:01:09.150
there's no Ruby in the crowd - OK. As

0:01:09.150,0:01:11.170
with every marriage you also need to know[br]the

0:01:11.170,0:01:14.049
other side. You know the side you were -

0:01:14.049,0:01:16.840
you didn't know when you were just going around.

0:01:16.840,0:01:19.990
But it's the same thing with Ruby. You have

0:01:19.990,0:01:22.880
to know what you're looking at. And my talk

0:01:22.880,0:01:25.840
is going to be about the weirdness and the

0:01:25.840,0:01:29.549
gotcha moments. In short, in my talk, if you

0:01:29.549,0:01:35.689
find 'Ah-ha!' moments, it's working. Oh, we[br]have a

0:01:35.689,0:01:40.329
varied audience today. So to ensure sanity,[br]I have

0:01:40.329,0:01:44.119
tagged my slides. My slides are tagged with[br]my

0:01:44.119,0:01:48.920
good friend bumblebee to keep it neutral,[br]that these

0:01:48.920,0:01:52.149
are for beginners. So you must pay attention.[br]And

0:01:52.149,0:01:54.729
the experts, try to give the beginners a chance

0:01:54.729,0:01:58.990
to give the answer. And the experts, you know,

0:01:58.990,0:02:03.219
take your inspiration from Optimus Prime.[br]And the beginners

0:02:03.219,0:02:05.789
can choose to tune out, but whatever you learn,

0:02:05.789,0:02:09.970
the better. So let's get started with the[br]infamous

0:02:09.970,0:02:16.970
infinity. Now, we all know what infinity is,[br]right?

0:02:17.860,0:02:20.569
And since we are all programmers, obviously[br]we should

0:02:20.569,0:02:23.830
know the answer to this one. What's the answer?

0:02:23.830,0:02:29.090
There are no surprises here. No surprises[br]there. No

0:02:29.090,0:02:32.520
division by zero. We know this. What about,[br]what

0:02:32.520,0:02:39.520
about this? Oops. This actually works. So[br]we know

0:02:40.000,0:02:43.870
that everything in Ruby is an object. So that

0:02:43.870,0:02:45.540
looks like a, that looks like a class. So

0:02:45.540,0:02:47.760
let's see what the hell that is anyway. If

0:02:47.760,0:02:50.170
you type this out, what do you think I

0:02:50.170,0:02:54.659
get? So... what's going on here? So infinity[br]is

0:02:54.659,0:02:57.230
a constant define in the float class. Where[br]do

0:02:57.230,0:02:59.560
you see it, you don't see it there. I

0:02:59.560,0:03:01.989
can use this constant to form range comparisons.[br]I

0:03:01.989,0:03:04.629
can use it with equality operators and stuff[br]like

0:03:04.629,0:03:08.799
that. Imagine three equal to equal to infinity.[br]But

0:03:08.799,0:03:13.260
it works. Oh well. So. This is the way

0:03:13.260,0:03:15.829
I get people warmed up. Let's do something[br]with

0:03:15.829,0:03:19.450
more of an adrenaline rush. Base conversions.[br]It's a

0:03:19.450,0:03:22.930
lot of fun. So what do you think is

0:03:22.930,0:03:27.469
the output of this particular thing? Now,[br]I don't

0:03:27.469,0:03:29.640
want all the math geeks going to their calculators,

0:03:29.640,0:03:34.890
but essence is converting a number to a string

0:03:34.890,0:03:38.700
in the octal format. So again, no surprises.[br]Should

0:03:38.700,0:03:45.469
be fine. But let's push the tempo. Now what?

0:03:45.469,0:03:51.060
That, actually works. The next time you are[br]reading

0:03:51.060,0:03:54.439
about, and you hear a name like getafix, ??

0:03:54.439,0:03:59.000
(00:03:57:07). You know oblix, asterix. It[br]need not be

0:03:59.000,0:04:04.620
a name, it could be a number. Well, now

0:04:04.620,0:04:11.620
what? Push the limits. Oops. So now if you

0:04:12.599,0:04:14.980
look at it a little logically, the radix as

0:04:14.980,0:04:17.720
a portion ?? (00:04:15:18) is supported only[br]in thirty-six,

0:04:17.720,0:04:20.858
because you have twenty-six alphabets and[br]ten digits. So

0:04:20.858,0:04:21.829
it can go only up to a radix of

0:04:21.829,0:04:26.240
thirty-six. So if there are some innovators[br]out there,

0:04:26.240,0:04:30.370
who want to actually get a new alphabet into

0:04:30.370,0:04:32.940
the English dictionary, we could probably[br]have a radix

0:04:32.940,0:04:39.940
of thirty-seven. OK. Let's move on to the[br]star.

0:04:41.180,0:04:43.870
Not the rock star, but the star operator.[br]And

0:04:43.870,0:04:46.180
to start with, let's see what it has to

0:04:46.180,0:04:50.150
do with Splat Expander. Oh boy, we see more

0:04:50.150,0:04:53.550
and more of Ruby code right now. So what

0:04:53.550,0:04:58.030
do you think is name and occupation here?[br]As

0:04:58.030,0:05:00.990
we can see we have a struct which takes,

0:05:00.990,0:05:05.120
which has two somethings, name and occupation,[br]and I

0:05:05.120,0:05:09.949
create an object off the struct. Now what[br]do

0:05:09.949,0:05:15.160
we see? Nothing fancy. We're still good. Right?[br]So

0:05:15.160,0:05:17.580
the Splat Expander is actually taking my arguments[br]and

0:05:17.580,0:05:20.600
given me the right name and the right occupation.

0:05:20.600,0:05:21.949
But we don't do things like this, do we?

0:05:21.949,0:05:25.930
We usually - we are Rails programmers. We[br]work

0:05:25.930,0:05:27.900
in Rails, so we usually have stuff like this.

0:05:27.900,0:05:31.639
We use keyword arguments. We all have keyword[br]arguments

0:05:31.639,0:05:34.520
to initiate a class like this and stuff. What

0:05:34.520,0:05:41.520
is the output now? It's Optimus Prime, so,[br]the

0:05:42.800,0:05:47.780
experts? What is name and occupation? Here[br]it's changed.

0:05:47.780,0:05:52.280
That's because the struct always has an array[br]of

0:05:52.280,0:05:54.800
arguments. It does not differentiate between[br]this. This will

0:05:54.800,0:05:59.009
not work on a class. Well, let's get to

0:05:59.009,0:06:04.490
something more funny. What about this? How[br]many here

0:06:04.490,0:06:07.889
have used this before? We know how to convert

0:06:07.889,0:06:09.729
an array into hash. How many of you have

0:06:09.729,0:06:13.590
used this notation before? All right-y, I[br]have two

0:06:13.590,0:06:17.780
people in the audience. Excellent. What happens[br]now? What

0:06:17.780,0:06:20.629
does this do? It actually converts to a hash.

0:06:20.629,0:06:23.729
And out of curiosity what if I add a

0:06:23.729,0:06:29.759
seventh element in the array? Error. No like,[br]dude,

0:06:29.759,0:06:31.069
I don't know what to do, what should I

0:06:31.069,0:06:34.330
do with the last one? Well, let's try some

0:06:34.330,0:06:37.800
more stars. Who all thinks that the output[br]of

0:06:37.800,0:06:43.460
this is gonna be three, six, and nine? Who

0:06:43.460,0:06:50.460
all think otherwise? What's the output? Awesome.[br]And now?

0:06:52.199,0:06:59.199
That was easy wasn't it? Now what? String[br]??

0:07:03.370,0:07:08.310
(00:07:04:24). That's all actually works.[br]And let's take it

0:07:08.310,0:07:11.190
to the next level. How many here know about

0:07:11.190,0:07:14.830
Stabby, Stabby proc? Here is a sample. So[br]this

0:07:14.830,0:07:17.489
is a Stabby proc that we have which takes

0:07:17.489,0:07:21.750
- note we are still working with star. So

0:07:21.750,0:07:23.909
if I make an invocation ?? (00:07:23:07) to[br]the

0:07:23.909,0:07:30.909
block like this, what is the output? Mumbling,[br]mumbling,

0:07:32.550,0:07:39.550
mumbling. It's five. And now you say, I knew

0:07:40.259,0:07:42.379
that. Right. So basically the short form for[br]the

0:07:42.379,0:07:45.629
first, second last, last, and the rest of[br]the

0:07:45.629,0:07:49.289
stuff is in the middle. Pretty helpful thing[br]to

0:07:49.289,0:07:52.050
know. This works on all. It not, it's just

0:07:52.050,0:07:54.000
not worked with the Stabby proc, it'll work[br]with

0:07:54.000,0:07:58.180
Lambda, it'll work with a method, too. But,[br]as

0:07:58.180,0:08:00.930
with Ruby, and, if I'm supposed to be standing

0:08:00.930,0:08:03.870
here and I'm supposed to be lecturing you[br]on

0:08:03.870,0:08:06.919
all this, I'm supposed to know my stuff. Lo

0:08:06.919,0:08:11.090
and behold, when I was trying these experiments,[br]I

0:08:11.090,0:08:14.419
learned something new. What do you think is[br]the

0:08:14.419,0:08:18.870
output of that? That actually works, and I[br]have

0:08:18.870,0:08:22.289
freaking no idea how. So, well let's put in

0:08:22.289,0:08:24.770
the slide, and if I have somebody looking[br]explain

0:08:24.770,0:08:27.150
to me how does that dot notation just work?

0:08:27.150,0:08:29.490
And it works only on this. It will not

0:08:29.490,0:08:31.590
work on a method obviously, right. But it[br]works!

0:08:31.590,0:08:38.590
So, welcome to the weirdness of Ruby. Well.[br]Getting

0:08:38.620,0:08:44.240
onto really complex stuff. Case statements.[br]How many of

0:08:44.240,0:08:45.600
you have - you all have used cases, right?

0:08:45.600,0:08:47.240
Case when and stuff like that. Why do you

0:08:47.240,0:08:50.060
think this works? And I've tried to make the

0:08:50.060,0:08:54.580
example as complex as possible. All right.[br]If Optimus

0:08:54.580,0:08:56.680
Prime doesn't do this who the hell else would,

0:08:56.680,0:09:03.680
right? So what is the output? It's pretty[br]obvious

0:09:04.300,0:09:06.320
that we have a multiple of three, because[br]nine

0:09:06.320,0:09:08.329
is a multiple of three, and yeah, because[br]we

0:09:08.329,0:09:10.450
can all read in English and Ruby gives us

0:09:10.450,0:09:14.880
readable code. We know the output here, right?[br]Well

0:09:14.880,0:09:17.870
it's true. You're absolutely right. Ruby's[br]not that weird.

0:09:17.870,0:09:20.170
It'll give you the right answers. But my question

0:09:20.170,0:09:25.870
is: multiple_of is a method, right? It takes[br]one

0:09:25.870,0:09:30.430
parameter, which I have passed. How was it[br]compared

0:09:30.430,0:09:37.430
with nine? Where did nine come into the picture?

0:09:39.540,0:09:43.610
Behind every case, behind every successful[br]case, is a

0:09:43.610,0:09:46.790
case equality operator. So what actually happens[br]is that

0:09:46.790,0:09:50.480
that number nine is used with a case equality

0:09:50.480,0:09:54.839
operator. And that case equality operator[br]is an alias

0:09:54.839,0:09:58.380
to the proc call, which actually gets us our

0:09:58.380,0:10:02.970
output. Well. Though this seems pretty straightforward,[br]it has

0:10:02.970,0:10:08.550
just given me immense power. I can now manipulate

0:10:08.550,0:10:10.620
any way that I want a case equality operator

0:10:10.620,0:10:14.630
to work. Simply by over riding the equal to

0:10:14.630,0:10:16.240
equal to equal to method - the case equality

0:10:16.240,0:10:19.260
operator. And I am good to have any sort

0:10:19.260,0:10:21.610
of case comparisons that I want to make. I

0:10:21.610,0:10:24.329
don't care what happens, but it's my call[br]anymore,

0:10:24.329,0:10:28.079
right. Speaking of case equality operator,[br]let's go to

0:10:28.079,0:10:30.269
equality. How many of you all know these symbols?

0:10:30.269,0:10:34.040
There are operators, an eql question mark,[br]and equal

0:10:34.040,0:10:41.040
question mark. Let's have some fun. Any takers?[br]Who

0:10:43.430,0:10:46.459
all think the output is true? Who all think

0:10:46.459,0:10:50.170
the output is false? What happened to the[br]rest

0:10:50.170,0:10:55.360
of the people? Don't care. Don't care. That's[br]bad

0:10:55.360,0:10:56.950
for a conference. You know we just got a

0:10:56.950,0:10:58.230
huge lecture about participation! Again, who[br]all thinks it's

0:10:58.230,0:11:05.230
true? Who all think it's false? Why? Oh, come

0:11:05.480,0:11:09.380
on man, Ruby's gonna be really neat. Of course

0:11:09.380,0:11:14.519
it's true. Well, what do you think now? Anybody

0:11:14.519,0:11:18.940
think it's true? All right man. Stand up dude.

0:11:18.940,0:11:21.800
Please give him a welcome, because he's got[br]it

0:11:21.800,0:11:26.820
absolutely right. What the hell happened to[br]the rest?

0:11:26.820,0:11:29.399
Dude, we just saw the slide before about case

0:11:29.399,0:11:31.720
equality. Are you telling me if you use that

0:11:31.720,0:11:34.790
in a when statement it's not gonna work? Of

0:11:34.790,0:11:39.730
course it's gonna work. You're just comparing[br]to one.

0:11:39.730,0:11:46.060
And... now what? True? How many people think[br]it's

0:11:46.060,0:11:52.260
true? How many people think it's false? Why?[br]So

0:11:52.260,0:11:54.209
people called false but thought it was true[br]but

0:11:54.209,0:11:57.389
didn't want to answer. Well it's false, and[br]I've

0:11:57.389,0:11:59.110
got you guys so motivated you don't want to

0:11:59.110,0:12:02.959
answer, right. Damn it. But this is actually[br]equality

0:12:02.959,0:12:05.680
by value. So the value returned by the object

0:12:05.680,0:12:08.720
is one, the value returned by the float is

0:12:08.720,0:12:14.430
a floating point one. It's completely different.[br]Now what?

0:12:14.430,0:12:18.300
Now it's interesting. Why is it false? Somebody[br]said

0:12:18.300,0:12:25.300
very confidently, why is it false? Absolutely.[br]Now here's

0:12:25.430,0:12:29.100
the weirdness. This stuff actually compares[br]the object ID

0:12:29.100,0:12:30.829
of the two, and a integer and a float

0:12:30.829,0:12:34.670
would have two different object IDs. It's[br]obvious, right

0:12:34.670,0:12:40.040
fellas? So. Aiy aiy aiy, true false, what's[br]it

0:12:40.040,0:12:47.040
guys? There string 'a' and string 'a' are[br]two

0:12:47.240,0:12:52.329
different ruby objects. If I switch that two[br]a

0:12:52.329,0:12:54.600
symbol - thank you that's where you go. So

0:12:54.600,0:13:00.760
with that, let's hit the jackpot. How many[br]of

0:13:00.760,0:13:03.490
you all know what curry is? It's a lot

0:13:03.490,0:13:06.410
of fun, a lot of fun. But to make

0:13:06.410,0:13:10.389
it funnier, I actually decided let's have[br]the slot

0:13:10.389,0:13:13.940
machine get three pulls. And I wrote code[br]for

0:13:13.940,0:13:17.370
it on my flight here, so I have no

0:13:17.370,0:13:20.160
idea whether that's correct or wrong, but[br]like, we

0:13:20.160,0:13:23.579
know it seems a little weird though. I've[br]tried

0:13:23.579,0:13:26.579
to compare if all the three pulls are equal

0:13:26.579,0:13:31.730
and then I'm preparing some recipe with curry,[br]and

0:13:31.730,0:13:37.350
do you think it would work? It just looks

0:13:37.350,0:13:40.810
a little bit of weird code, but I shall

0:13:40.810,0:13:46.850
explain. So curry is a method in the proc

0:13:46.850,0:13:51.769
class which actually returns a lambda if all[br]the

0:13:51.769,0:13:55.010
parameters are not fulfilled. So in this particular[br]case,

0:13:55.010,0:13:57.790
I needed three parameters, X, Y, and Z, and

0:13:57.790,0:14:00.760
in the first statement, I passed only one.[br]Note,

0:14:00.760,0:14:04.040
the invocation is in square brackets. It's[br]different. And

0:14:04.040,0:14:06.720
it returns me a lambda, but other times when

0:14:06.720,0:14:09.420
all the parameters are actually fulfilled[br]in the second

0:14:09.420,0:14:13.420
statement, it actually evaluates the proc.[br]Now if you

0:14:13.420,0:14:15.610
had to write the same code you would have

0:14:15.610,0:14:18.459
taken different types of input, weighted for[br]the user

0:14:18.459,0:14:23.290
with (00:14:18:29) ...?? one, two, three,[br]and evaluated it.

0:14:23.290,0:14:24.920
You don't need to do that. And these things

0:14:24.920,0:14:31.920
can actually be very helpful. So curry away.[br]So!

0:14:34.300,0:14:41.300
So you think you can tell protected from private.

0:14:41.949,0:14:44.320
OK, I am not a - I'm a better

0:14:44.320,0:14:50.360
programmer than a singer. Right. Private methods.[br]All of

0:14:50.360,0:14:54.000
us have been taught since school, unfortunately,[br]that private

0:14:54.000,0:14:58.740
methods are not inherited. Are they inherited?[br]As you

0:14:58.740,0:15:01.259
can see, foo is a private method. And I

0:15:01.259,0:15:02.910
ran out of creativity, so I just went to

0:15:02.910,0:15:06.060
the standard base type foo, blah blah blah[br]here.

0:15:06.060,0:15:10.620
Is this going to work? All of us take

0:15:10.620,0:15:13.070
a lot of things for granted. How many of

0:15:13.070,0:15:14.420
you all knew this already, that private methods[br]are

0:15:14.420,0:15:18.500
inherited in Ruby? All right, OK, now I'm[br]scared.

0:15:18.500,0:15:21.160
How many of you all didn't know this? Don't

0:15:21.160,0:15:24.610
be shy, don't be shy. OK, so this is

0:15:24.610,0:15:28.079
actually one of the basic principles of where[br]Ruby

0:15:28.079,0:15:32.339
actually breaks traditional object oriented[br]concepts. All private methods

0:15:32.339,0:15:36.699
are inherited. What? How many of you all have

0:15:36.699,0:15:41.860
seen this code before? Forget the Mongoid::Document[br]but include?

0:15:41.860,0:15:46.029
Wait, come on. Everybody knows it! What is[br]include?

0:15:46.029,0:15:53.029
Is it a keyword? How many thought it was

0:15:53.139,0:15:55.120
a keyword? Oh it's like that, require or that

0:15:55.120,0:16:01.639
import in Java. Include is a private instance[br]method

0:16:01.639,0:16:07.500
defined in the class module. So while that[br]is

0:16:07.500,0:16:10.980
sinking in, it raises a basic question. All[br]private

0:16:10.980,0:16:17.980
methods are inherited. So what are protected[br]methods? So

0:16:18.269,0:16:19.889
what about protected methods? So what's the[br]difference between

0:16:19.889,0:16:23.089
private methods and protected methods now?[br]We were told

0:16:23.089,0:16:27.290
in our school that protected methods are inherited[br]but

0:16:27.290,0:16:32.110
not publicly accessible, right. Now private[br]methods are inherited

0:16:32.110,0:16:36.649
but not publicly accessible, right? So what[br]are private

0:16:36.649,0:16:41.130
metho- protected methods? Contrary to popular[br]belief, in Ruby

0:16:41.130,0:16:46.490
protected methods actually work with objects[br]and not classes.

0:16:46.490,0:16:49.610
And you can invoke a protected method on another

0:16:49.610,0:16:54.339
object within the same lineage. And I say,[br]what

0:16:54.339,0:17:01.339
the... what? Better explained with an example.[br]Simple example,

0:17:01.610,0:17:03.060
for the sake of brevity I put the initializer

0:17:03.060,0:17:09.230
in one line. What is the output, people? Don't

0:17:09.230,0:17:15.040
be shy. You have bumblebee to help you out.

0:17:15.040,0:17:19.990
No takers. Come on man, that's like pretty[br]obvious

0:17:19.990,0:17:23.050
right. You can't call a protected method on[br]an

0:17:23.050,0:17:30.050
object, right? Simple stuff. However. Now[br]beginners, so-called beginners

0:17:31.340,0:17:33.430
can tune out. This is fun. I added a

0:17:33.430,0:17:38.740
method called fights. Same piece of code.[br]What is

0:17:38.740,0:17:44.070
the output? Take a wild guess, man. Go for

0:17:44.070,0:17:51.070
it. So either Megatron or Decepticon. Any[br]other deceptive

0:17:52.350,0:17:59.350
ideas? Guys, very practically, a quick lesson[br]in human

0:17:59.880,0:18:02.710
psychology. If that didn't work, would I have[br]that

0:18:02.710,0:18:08.150
slide up there again? It works, man. It works.

0:18:08.150,0:18:09.940
But why did it work and how did it

0:18:09.940,0:18:13.430
work? The interesting part is that piece of[br]line,

0:18:13.430,0:18:15.660
earlier in the previous slide, prime dot nick[br]did

0:18:15.660,0:18:18.550
not work, but here target dot nick actually[br]works.

0:18:18.550,0:18:22.120
I have called a protected method on an object.

0:18:22.120,0:18:25.960
Now that same lineage means that because I'm[br]inside

0:18:25.960,0:18:28.950
the class Autobot, because I'm calling a method[br]on

0:18:28.950,0:18:32.320
the prime object, which is in, which is in

0:18:32.320,0:18:36.190
Autobot class, and since another object called[br]Megatron there

0:18:36.190,0:18:40.810
is of the same lineage, it's also an Autobot.

0:18:40.810,0:18:46.850
I can call the protected methods. So why didn't

0:18:46.850,0:18:49.900
it work earlier? Because everything in Ruby[br]is an

0:18:49.900,0:18:52.340
object. If you're trying to start prime dot[br]nick

0:18:52.340,0:18:55.140
and the previous case was outside the scope.[br]So

0:18:55.140,0:18:57.640
it was effectively in some main class, not[br]the

0:18:57.640,0:19:00.730
same lineage, so it doesn't work. So Ruby[br]actually

0:19:00.730,0:19:04.400
works in the traditional way, but has different[br]internal

0:19:04.400,0:19:07.380
meanings. And if now this was getting a little

0:19:07.380,0:19:10.430
complicated, how many of you all thought there[br]are

0:19:10.430,0:19:12.430
keywords in Ruby? Cause that man there is[br]gonna

0:19:12.430,0:19:14.260
come and shoot you if you think Ruby has

0:19:14.260,0:19:21.260
keywords. Does that code work? Is it even[br]valid?

0:19:23.700,0:19:29.640
Should it give me a syntax error? If, how

0:19:29.640,0:19:30.990
many of you think it will give me an

0:19:30.990,0:19:33.460
error? Syntax error too? What's wrong with[br]you? Have

0:19:33.460,0:19:37.070
you gone mad?-kind of errors. Any takers for[br]syntax

0:19:37.070,0:19:40.010
errors? Probably not. But if not, then I want

0:19:40.010,0:19:41.280
to ask you know what is the output of

0:19:41.280,0:19:48.280
this code? Seriously. There it is, seriously.[br]Question is,

0:19:50.440,0:19:51.710
how many of you all thought this is an

0:19:51.710,0:19:55.400
error called stack_too_deep. Cause when I[br]call false it

0:19:55.400,0:19:57.770
calls true, once you call true it will call

0:19:57.770,0:20:02.250
false. And it goes into a recursive loop and

0:20:02.250,0:20:08.330
case stack_too_deep. Any takers for stack_too_deep?[br]Higher, higher! And

0:20:08.330,0:20:12.240
how many think it will actually work? All[br]right.

0:20:12.240,0:20:15.510
The rest of the people, you all are beginners.

0:20:15.510,0:20:17.300
But yeah this works. So it does not stack_too_deep.

0:20:17.300,0:20:21.680
This actually works because true, true's resolution[br]is immediately

0:20:21.680,0:20:24.800
determined as the boolean value. However if[br]I had

0:20:24.800,0:20:29.650
changed these two particular statements, the[br]content in the

0:20:29.650,0:20:32.130
methods to self dot false and self dot true

0:20:32.130,0:20:39.130
I would probably get stack_too_deep. Not probably,[br]definitely get

0:20:39.190,0:20:42.270
stack_too_deep. OK. So. If this wasn't complex[br]enough for

0:20:42.270,0:20:49.200
you, let's go to modules, the mysterious modules.[br]You

0:20:49.200,0:20:51.030
know what the bull I have with my good

0:20:51.030,0:20:54.660
friend module, which has power, Megatron is[br]super powerful,

0:20:54.660,0:20:57.990
and he's a force, he's evil. And I want

0:20:57.990,0:21:00.910
to put that in my class Hanuman. note the

0:21:00.910,0:21:04.070
star, because that's true. I want the power[br]of

0:21:04.070,0:21:10.590
Megatron with Hanuman. Hanuman! Unfortunately[br]this will not go

0:21:10.590,0:21:13.460
down too well religiously for us, because[br]though it

0:21:13.460,0:21:15.890
will be Hanuman will be as powerful as Megatron,

0:21:15.890,0:21:19.960
Hanuman is now evil! So what do I do?

0:21:19.960,0:21:22.560
Is there a way I can cherry-pick from Megatron,

0:21:22.560,0:21:25.650
saying, I want the power of Megatron but I

0:21:25.650,0:21:32.650
don't want to be evil? What do I do?

0:21:33.060,0:21:35.700
I require. Note, I have not included Megatron,[br]I

0:21:35.700,0:21:39.980
require the Megatron method- Megatron file,[br]Megatron RB. I

0:21:39.980,0:21:43.270
define a method called power and I go to

0:21:43.270,0:21:46.190
the module, tell him to give me that instance

0:21:46.190,0:21:49.600
method called power, which gives me something[br]called an

0:21:49.600,0:21:54.030
unbounded method. And then I bind it to me,

0:21:54.030,0:21:59.730
that is self, and I call it. And that

0:21:59.730,0:22:06.730
makes my Hanuman religiously acceptable to[br]society. Question? No.

0:22:09.150,0:22:11.870
So note self, self is the object call. So

0:22:11.870,0:22:13.680
it's not working on the class call, it's actually

0:22:13.680,0:22:16.260
working on the instance. So every object,[br]every instance

0:22:16.260,0:22:21.660
of Hanuman, will actually get the power of[br]Megatron.

0:22:21.660,0:22:26.890
And with that I end my talk and thank

0:22:26.890,0:22:29.980
my two assistants here. I have, I'm open for

0:22:29.980,0:22:33.820
a few questions. Do I have the time, guys?

0:22:33.820,0:22:35.910
Satish, do I have some time? For questions?[br]Yay!

0:22:35.910,0:22:40.650
We have a lot of time for questions! All

0:22:40.650,0:22:47.650
right, you. Thank you. You have a question[br]there.

0:22:49.190,0:22:52.970
QUESTION: What exactly lead you to title this[br]talk

0:22:52.970,0:22:56.840
as the Dark Side of Ruby? G.R.: Oooh. Now

0:22:56.840,0:22:59.660
he killed me, didn't he? So that was a,

0:22:59.660,0:23:01.510
there's a two-sided answer to that. One was[br]to

0:23:01.510,0:23:06.020
fool the organizers, to get the CF?? (00:23:05:23)[br]accepted.

0:23:06.020,0:23:10.510
But more importantly, the dark side of Ruby[br]tries

0:23:10.510,0:23:12.130
to bring out the weirdness in Ruby, which[br]is

0:23:12.130,0:23:15.700
not the evil part, but the hidden part. Like

0:23:15.700,0:23:18.130
the dark side of the moon where we have

0:23:18.130,0:23:20.180
all these kind of stuff that breaks, the gotchas,

0:23:20.180,0:23:22.870
the moment that we feel that are going to

0:23:22.870,0:23:25.740
help but you don't really need to care about

0:23:25.740,0:23:28.160
it, but it's really, really important that[br]you know

0:23:28.160,0:23:32.840
these things exist. That's why Dark Side of[br]Ruby.

0:23:32.840,0:23:37.920
So I still love Ruby - no offense. Any

0:23:37.920,0:23:44.920
other questions? Yes sir. QUESTION: So have[br]you suffered

0:23:45.120,0:23:47.040
because of any of these gotchas in you work?

0:23:47.040,0:23:50.940
G.R.: Absolutely! This is all part of experience.[br]Part

0:23:50.940,0:23:55.860
(00:23:53:00 ??) is part of experience, part[br]is training,

0:23:55.860,0:23:59.310
and partly is preparation for my talk, trying[br]to

0:23:59.310,0:24:02.030
find out these terms, and figuring things[br]out. There's

0:24:02.030,0:24:04.170
a lot of stuff that I've actually kept out,

0:24:04.170,0:24:08.370
like you know ?? (00:24:07:03) games. Lots[br]of fun

0:24:08.370,0:24:10.850
with method missing. I haven't even touched[br]upon blocks

0:24:10.850,0:24:12.970
and ?? There's lots of funny stuff which happens

0:24:12.970,0:24:17.130
there. But I have only half an hour. So

0:24:17.130,0:24:18.450
the question to you guys also is that in

0:24:18.450,0:24:20.260
case you find some of these funny things which

0:24:20.260,0:24:23.040
happen in Ruby, and are able to explain it

0:24:23.040,0:24:24.770
or not able to explain it, send me a

0:24:24.770,0:24:27.580
Tweet, send me an email, and I will probably

0:24:27.580,0:24:30.600
investigate and improve my talk at your expense.[br]QUESTION:

0:24:30.600,0:24:35.380
Yeah. So the other question is, are there[br]some

0:24:35.380,0:24:39.850
practices, certain things that I follow, so[br]that I

0:24:39.850,0:24:42.730
don't get, I don't encounter these? G.R.:[br]Well, so

0:24:42.730,0:24:44.220
one thing, these aren't problems. What I wanted[br]to

0:24:44.220,0:24:45.900
point out here is that this is not a

0:24:45.900,0:24:47.390
bad part of Ruby, but these are the things

0:24:47.390,0:24:50.130
that we take for granted. So knowing about[br]protected

0:24:50.130,0:24:55.050
and private being different is important.[br]But not mandatory

0:24:55.050,0:24:57.910
for us to work as Rails programmers. But if

0:24:57.910,0:25:01.750
you know that, how protected and private actually[br]work,

0:25:01.750,0:25:05.050
it makes us better programmers. So best practices[br]of

0:25:05.050,0:25:07.450
Ruby are already there. You know there are[br]things

0:25:07.450,0:25:11.380
like flip-flops in Ruby which is for lack[br]of

0:25:11.380,0:25:15.220
a better term, a mind star star star star.

0:25:15.220,0:25:18.010
But, I do not recommend it. But it's there.

0:25:18.010,0:25:20.860
There are plenty of other things in Ruby,[br]too.

0:25:20.860,0:25:24.620
Which work, which should work, which you should[br]use.

0:25:24.620,0:25:26.970
The bottom line is that Ruby gives us the

0:25:26.970,0:25:29.530
maximum flexibility to build the way we want[br]to

0:25:29.530,0:25:33.050
build our code. So with great power comes[br]great

0:25:33.050,0:25:35.530
responsibility. And sometimes it's irresponsible.[br]So it worked out

0:25:35.530,0:25:39.040
great. Yeah. QUESTION: So is there a good[br]parts

0:25:39.040,0:25:41.460
of Ruby, like good parts of Java- G.R.: What?

0:25:41.460,0:25:43.890
QUESTION: Good parts of Ruby? G.R.: Oh, good[br]parts?

0:25:43.890,0:25:45.650
Everything! I've been working in Ruby for[br]six years

0:25:45.650,0:25:48.050
and I still love it. QUESTION: No, there is

0:25:48.050,0:25:49.320
a famous book called Good Parts of JavaScript,[br]a

0:25:49.320,0:25:51.600
very thin book that allows a subset of language

0:25:51.600,0:25:55.600
that is very safe to use, that you can

0:25:55.600,0:26:02.110
be very productive in. So do you, have you

0:26:02.110,0:26:02.200
come across something that says, like, there's[br]a subset

0:26:02.200,0:26:02.300
that you should stick to and use? G.R.: So

0:26:02.300,0:26:05.390
the best part about Ruby that I like is

0:26:05.390,0:26:09.070
the closures, which is completely misunderstood,[br]because every time

0:26:09.070,0:26:11.390
I talk to any person who's getting into Ruby

0:26:11.390,0:26:12.620
and I show them what a closure is they're

0:26:12.620,0:26:15.060
like yeah, that's a loop. But it's not. It's

0:26:15.060,0:26:17.670
like far more better than that. And it's far

0:26:17.670,0:26:20.660
more - it's more intuitive. It gets into the

0:26:20.660,0:26:23.410
details and gives us so much more incentive[br]about

0:26:23.410,0:26:26.160
learning how Ruby internals work, that we[br]tend to

0:26:26.160,0:26:29.100
actually ignore it in Rails. And I only (00:26:30:29)

0:26:29.100,0:26:31.530
have a lot of respect for people who have

0:26:31.530,0:26:33.010
learned Ruby and gone to Rails, because they[br]know

0:26:33.010,0:26:35.790
the right thing, other than most of us, including

0:26:35.790,0:26:38.340
me, who got into Rails and then fell in

0:26:38.340,0:26:41.770
love with Ruby. So it's different. QUESTION:[br]So is

0:26:41.770,0:26:46.310
Ruby the good parts the next book? G.R.: Could

0:26:46.310,0:26:48.090
be. But I'll need a lot of community support

0:26:48.090,0:26:54.900
for that. Yes? QUESTION: Yeah, hi, thanks[br]for the

0:26:54.900,0:26:57.390
talk. Just (00:26:55:09). I have been checking[br]out Exorcism

0:26:57.390,0:26:59.030
dot IO. I don't know if you guys have

0:26:59.030,0:27:01.750
heard of it. So it's actually started by Katrina,

0:27:01.750,0:27:04.000
who's part of the Ruby Rogues, and I have

0:27:04.000,0:27:06.530
had a wonderful time running stuff from Ruby,[br]like

0:27:06.530,0:27:08.940
I have been working Ruby for ?? (00:27:08:20)[br]for

0:27:08.940,0:27:11.650
years and also gotchas- G.R.: So, Exorcism[br]dot IO.

0:27:11.650,0:27:14.560
That's great. QUESTION: Like really good Ruby[br]idioms that

0:27:14.560,0:27:15.500
like so it's basically what happens is you,[br]there

0:27:15.500,0:27:17.210
are around ten languages if I'm not wrong.[br]You

0:27:17.210,0:27:21.160
can pick Ruby, you can sub in your solutions.

0:27:21.160,0:27:23.660
People can look at your code. They can give

0:27:23.660,0:27:26.810
good reviews. You can help out others with[br]your

0:27:26.810,0:27:30.190
suggestions. Yeah- G.R.: But to add to that,[br]there

0:27:30.190,0:27:32.370
is also some interesting - I'm not sure if

0:27:32.370,0:27:35.870
you all have heard of Winbgall (00:27:33:08).[br]Wingolf was

0:27:35.870,0:27:38.670
a gem and a simple tool where you can

0:27:38.670,0:27:42.150
report a problem statement, and using whim,[br]you know

0:27:42.150,0:27:46.150
execute that in the least number of key presses.

0:27:46.150,0:27:48.650
Similarly there are a few initiatives for[br]Ruby golf,

0:27:48.650,0:27:51.350
where you can actually try things like, the[br]beginner

0:27:51.350,0:27:54.210
?? they actually said they have things with[br]??

0:27:54.210,0:27:57.790
you know stuff like, write this piece of code

0:27:57.790,0:28:01.130
without using arrays, or without using the[br]equality operator.

0:28:01.130,0:28:03.500
And then you start, your mind starts churning,[br]and

0:28:03.500,0:28:05.090
then you dig deeper into Ruby and find other

0:28:05.090,0:28:07.140
things. So the best way to find these things

0:28:07.140,0:28:10.850
is to try Ruby ?? All right we had

0:28:10.850,0:28:13.380
a question there too. QUESTION: Not really[br]a question,

0:28:13.380,0:28:16.210
but just a suggestion, actually, to folks[br]who are

0:28:16.210,0:28:18.740
trying to learn Ruby. I like that he pointed

0:28:18.740,0:28:20.700
out that some of the things that we've learned

0:28:20.700,0:28:24.290
in college, classical logic and stuff doesn't[br]really apply.

0:28:24.290,0:28:27.750
What really helped me understand differences[br]was that treat

0:28:27.750,0:28:30.840
Ruby as a object-focused language and most[br]of the

0:28:30.840,0:28:33.120
languages that you probably end up working[br]with, Java,

0:28:33.120,0:28:36.280
C sharp, they'll be class focused. So concepts[br]like

0:28:36.280,0:28:39.340
private, protected, just like you mentioned,[br]are all object-level

0:28:39.340,0:28:41.580
concepts in Ruby. In fact if you wanted to

0:28:41.580,0:28:44.570
draw parallels again JavaScript is a good[br]parallel because

0:28:44.570,0:28:47.230
JavaScript is also an object-focused language.[br]So there are a

0:28:47.230,0:28:48.950
lot of parallels between JavaScript and Ruby, and

0:28:49.000,0:28:51.700
less between Java and Ruby.

0:28:51.700,0:28:52.700
QUERANT: Yeah, and-

0:28:52.740,0:28:55.700
It's like the dot, I'm sorry, that dot thing just amazed me.

0:28:55.700,0:28:58.780
??, just having a dot.

0:28:58.900,0:29:01.460
and I was actually kind of disappointed when it

0:29:01.460,0:29:04.040
ended. I just wanted more. OK.

0:29:04.140,0:29:05.140
G.R.: Cool. Thank you.

0:29:08.260,0:29:09.260
Yes?

0:29:11.080,0:29:13.200
The Well-Grounded Rubyist. A must read.

0:29:14.260,0:29:15.680
V.O.: Somebody Tweet about it, please.

0:29:16.340,0:29:17.680
V.O.: We'll take one last question.

0:29:19.500,0:29:21.840
QUERANT: How does it help to have protected and private method

0:29:21.940,0:29:24.940
different from other languages? The way Ruby does it?

0:29:25.160,0:29:27.780
G.R.: I'm sorry. Did you ask what is different between protected and private-

0:29:27.780,0:29:30.140
QUERANT: No. How does it help to have a different design implementation,

0:29:30.140,0:29:31.140
to have it different.

0:29:31.140,0:29:33.720
G.R.: Oh. Excellent. And I love answering this question.

0:29:33.720,0:29:35.560
Though sometimes it can be a little long.

0:29:35.560,0:29:39.760
Why is private and protected different private and protected different in Ruby than

0:29:39.760,0:29:41.540
in other traditional standard languages?

0:29:41.540,0:29:43.160
Because Ruby did it right.

0:29:43.160,0:29:44.840
That's how it's supposed to be.

0:29:44.840,0:29:46.240
Example.

0:29:48.180,0:29:50.440
You know, when we talk about object-oriented programming,

0:29:50.440,0:29:52.680
it's supposed to be about objects. Things that you can see and touch.

0:29:52.680,0:29:55.060
For example: Inheritance.

0:29:55.060,0:29:57.020
Right. What is inheritance?

0:29:57.020,0:29:59.380
In, put it in, no uncertain term, though, it's my

0:29:59.380,0:30:01.080
??

0:30:01.820,0:30:04.900
Right. My inherited land my from my ancestors.

0:30:06.500,0:30:08.740
It's private. It's inherited.

0:30:08.740,0:30:11.620
You can. It, it comes within the family.

0:30:11.620,0:30:13.640
It can be protected. Can be private.

0:30:13.640,0:30:16.900
But, if you have your dad's wallet, do you inherit it?

0:30:18.280,0:30:20.440
You can choose to use it. You can choose not to use it.

0:30:20.500,0:30:21.620
It's just there.

0:30:21.620,0:30:24.980
The inheritance of land can be protected because it always stays in the family.

0:30:24.980,0:30:28.440
Like, for example, the money in the family is protected.

0:30:28.440,0:30:31.340
But that's always dealing with parents and children.

0:30:31.340,0:30:35.460
You can't go, your father. Just because you have a father and I have a father

0:30:35.460,0:30:37.000
I can't go asking your father for money.

0:30:37.000,0:30:40.700
Right. It's immense, how you determine. And of course public is the same everywhere.

0:30:41.260,0:30:43.960
So Ruby did it right, because it's, everything's object-centric.

0:30:44.680,0:30:47.940
Exactly what Aman said just now. Everything's object centric.

0:30:48.660,0:30:52.140
And, traditionally in object-oriented concepts, it started off right

0:30:52.140,0:30:57.020
and then it went all across the tangent, where you had this inheritance, and

0:30:57.020,0:30:59.120
classes and stuff like that. All the standard

0:31:00.060,0:31:06.480
things that I never talk about: incapsulation, abstraction, polymorphism

0:31:06.480,0:31:09.440
which seem to be the essence of object-oriented programming but is not.

0:31:10.240,0:31:11.840
V.O.: So, a follow-up question.

0:31:11.840,0:31:16.380
I have it. So is there a well-known pattern that makes use of, makes good of

0:31:16.380,0:31:18.200
private and protected?

0:31:18.980,0:31:19.980
We understand why- G.R.: Good qu-

0:31:19.980,0:31:20.980
QUERANT: Is it because it

0:31:20.980,0:31:24.400
G.R.: Include. Include. Include is an excellent example.

0:31:24.400,0:31:26.660
There are actually other patterns, too.

0:31:26.660,0:31:30.780
There are other patterns which allow for protected, protected is used very heavily for

0:31:30.780,0:31:34.080
all sorts of, the usually standard, why use protected, for example

0:31:34.080,0:31:37.180
protecting your password generation algorithm.

0:31:37.180,0:31:39.060
Something like that. But that's the deal with objects.

0:31:39.180,0:31:41.980
And since objects can be called only from their own lineage

0:31:41.980,0:31:43.940
you're always safe. Good question.

0:31:46.000,0:31:47.460
All right. V.O.: Anymore questions?

0:31:48.380,0:31:50.340
If there's anymore questions, we'll take it offline.

0:31:50.340,0:31:52.140
G.R.: Sure. Thank you so much

0:31:53.840,0:31:54.840
V.O.: Thanks Gautam.