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hey welcome everybody am

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in yet another jam session and

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for the functional programming 10 on X
course

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and and this one we're going to

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and do a quick run

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over Facebook's and extensions to bhp

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gold heck and and hack

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really is and one way to look at it its
PHP

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rate optional typing just like and art
an

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and then there's some act quiet a
interesting

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additional features that we have seen NC
sharp

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and and and artist while search as

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a synchronous functions and iterators an

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and then the the and additions

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that heck brings to bhp are

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optional static typing and show you in

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and year you can kinda yeah specify the
types

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and the other thing Islam the
expressions and we will

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am walked through some examples there as
well

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and examples will all be taken here from
the heck

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website and and I

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invite you to gonna have a look at it
and install hack

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am on your computer if you're a PHP
programmer

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an I think this is definitely step

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up let's look at first

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at and the

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way

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you use and anonymous functions and BHP

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so in PHP and maybe I can make this

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a little bit larger to make it better
readable

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so and BHP and like in C plus plus she
bus bus

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am as long as as well and when you
capture ferry boats from the outer scope

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you have to explicitly used them for
example here

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we're there's a variable dollar ax here
in

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and BHP and parables are

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and always have like this dollar sign in
front so we have a fair ball dollar axe

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that initialized to bar and here's an

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anonymous function that we return this
index is similar to Javascript or you

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have to write function

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parameter girly open body return so

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that's already rather for both but then
hears that

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you always have to be to say which

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their balls from the Ardeche hope you're
using an

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and so when you want to ride and

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goat in the higher-order style using

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filter and Matt an those kinda functions
that we have seen

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and Haskell course the syntex here

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becomes very very heavyweight an

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and you know there's more noise

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an then really what you gain 100

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very nice things in hac is that hack

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support love the expressions which makes

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the user anonymous functions and BHP

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much much more concise so and that's ok
at

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and the example here

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so an every ever

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a function that a captures be

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from the outer scope so that's used be
here

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but we don't have to say any use here

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and also this syntax is much more
concise

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weekend just say dollar a that's the
brand matter

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arrow and then triple arrow and the
website

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here baggage in very interesting
explanation of why

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thats index was used not single arrow or
not yeah

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single double arrow and but here you see
that we don't have to ride

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am old this an

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noise we don't have the right functions
we don't have to ride

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use and now suddenly writing
higher-order functions like Matt

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filter fault becomes and rather

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easy and so I thats that

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a quiet and nice thing good

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let's look at some other features of of
fact that we have seen in Haskell

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anti Bailey SS we have seen type aliases
also

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in Scala and Haskell if you want to give
a name

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a different name do some type you just
defined

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type alias and and hack

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you can do that here and there are

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a.m. also new type that's the same
concept

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as in has car and so on so I show

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hack has a number of ways to define

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died aliases and there you see here
dares

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and ok I'm all as mentioned an

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interestingly heck compiler itself is
written in OCaml

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an that's an example Ave

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very large piece of software written in
the functional language

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that is used at and you know a major
Internet company

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and and also many of the and

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ideas in hack have been

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entranced by and the O'Connell language

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so there you see another example where a
functional language

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ok I'm all is boat used in the
implementation

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of and dish %eh the an

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there every day but also did design

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of hack has been entranced by

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functional language Biochem and at

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very nice that's

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we've seen lund expressions here are

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an generators and in c-sharp their
shield return

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we've seen does in am dart as well with
the sink star Matt it's

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JavaScript ECMAScript 6 and will also
support

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yields and BHP

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already an support

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support generators here so you can

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and ride inside the function body you
can

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used yield and then the result %uh this

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and will be an an iterable

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and the nice thing about this is that if
you use these

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an iterators and I i haven't shown them
in C sharp in c-sharp

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I've shown an only the link
comprehension

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but with iterators its kind of the
impaired if

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equivalent of comprehension because
sometimes

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you want to generate an a collection

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but you want to maintain some states and
the you want to use regular control flow

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like dry catch em for loops and

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while loops and and in that case the

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an iterators

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or generators as there sometime called
are super convenient because

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it just allows you to write the same
kind of cotija right in normal

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function bodies but now you can

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temporarily suspend to function body
when you want to yield

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value and then when the consumer goals
move next

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execution continues here the other thing
that

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in and hack and that ish

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quite nice and that's also in c-sharp

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and as we've seen also in dart are

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an a synchronous functions so and

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if you define a function you say that
it's

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a synchronous an then inside that
function

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you can call await on another a
synchronous function

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and this a single instructions returns
and

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a way to bowl of an some value

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and the way to ball say roughly is

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what corresponds to a task in c-sharp
our future and job I

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or future and art an and

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so this awaits takes on the right hand
side

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a an await a ball of tea and then

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turns that into and eighty and

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under the covers at the compiler will
create

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a state machine that well and take the
continuation

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up this program here so there

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rest of the computation it's basically
am

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what's highlighted here and boss that as
the gold back

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and when that way to ball has terminated

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and I think that's a

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that's about it for an for for hack so
if you go to the heck website

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it well it has I am fantastic
documentation

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there's a lot of some balls tutorials

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an and and there's also

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I am instructions how to install it on
your own computer

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if your are a PHP programmer and

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and you're interested in using a much
more

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functional programming style I would
deftly

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and in our advice you

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to give hackett try an and as I
mentioned

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and heck compiler is written in OCaml

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an and so the influences functional
programming here

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are very apparent and which is always

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beautiful thank you very much and

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happy hacking