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K

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welcome everybody to another an jam
session

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in the a FB 1 along axed functional
programming course

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an and this a snippet

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I'm going to show howdy I deres and

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that we learnt in the main course and

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it has girl can be applied and

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in dotnet and in order to program dot
net

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I'll be using as ever in studio and

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Semoran is in open source implementation
of the dotnet framework

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this cross-platform so if you want to
ride codes

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a in C sharp or Visual Basic

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RXR only do sharp today but

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and summer and supports the other two
languages as well

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and if you want a ride cross-platform
don't that code that runs on the iPhone

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Android

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on Windows Phone on the Mac on Windows
as ever in studio

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is your tool of choice and because of
that

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and severance video is also my tool of
choice

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an but thats shutdown

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open up number in studio and write some
C sharp goat

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an using functions and C sharp

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as a couple of and dressing tourists

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an that we haven't seen

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and other languages so here is a.m. are
severance DDR

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and here is some sample

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C sharp got and

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as always an

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sharp requires and then that

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and it doesn't required to

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YouTube of the arguments if you don't
use them and here's the typical hello

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world

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console right line hello world and

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I fear is our first example avail on the
expressions or

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the right inside here X double arrow ECs
times do

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in Long expression that multiplies the
argument by two

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and I and at sign it

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do at here's another for my beloved
expression that defines a function from

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end to end H and and it takes

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parameter axe and then

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it uses a statement body and

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with curly braces so does our to do form
shoveling the expressions and here I

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print af

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and age now C sharp does support

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an type inference so I can ride yeah

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far and and Z

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equals 42 and when I do this

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an you see that

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that its hasn't worked and forty do it
the

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editor here says you know this is
redundant because I'm not using see

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anywhere

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but what I wanted to show you is that
you can define

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far here and the compiler

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well in for that she had is has died and
now you can

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ask yourself why I can't be huge type
inference here sure lets

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an dried to

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ride far here

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and let's not forget the dive

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and there is are far and that run this
code and now what you see here said

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it says implicitly typed local variable
declaration

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cannot be initialized with anonymous
Matt

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what does that all mean well the

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thing here is that in c-sharp

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I can use along the expression

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and like we do below here just

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go away good

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am here I defined

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another lund expression it's exactly the
same on the expression

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as here but instead of giving it to type

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a funk from end to end I

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say agent expression of funk

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from and and this is it a super
interesting

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aspect of C sharp where a

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love the expression by itself has no
type

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that's why I couldn't use type inference
there but the ban

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on the context where you sit on the
expression

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that long expression can't be turned
into college

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like here into a function or it can be

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third into daytime like here and

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into an expression and the price you pay

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for that magic where you can take and

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a long the expression and Bri presented

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as an coat and

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as daytime is the fact that you have to

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gonna explicitly type damn

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lech have a little appear G

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and she

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what intellisense tells us so what you
see here now

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is dead G has a body show that scan

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get geez body and then an

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here receive you have all kinda no
matter its

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on G so for example yeah can reduce et
cetera

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so this gives you a full API

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to manipulate this long expression

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as data and this mechanism is used very
happily for example

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in and Fri Mar like the Entity Framework

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and and the old and Asian link to see
call

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where you can take fragments like this
analyzed them

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and compile them to see call and set I'm
saying at

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mike is a free search has also done some
interesting work here for example where

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he takes these

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long the expressions and compiles them
into FPGA

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and people do all kinda interesting
thanks an

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and if you an our list programmer

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the way you would do this is using
quoting

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and and this is gonna see sharks way of
doing quoting

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using as static types

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and good and one thing that she sharp
doesn't have

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an and which we saw

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and and other languages that didn't work
for example ankle plan and

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skyline in dart

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is the idea local functions so you can
have a

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lund expression here and which is gonna
be a local punch but I cannot define

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an a function are matted just

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like I defined here and inside another
matter so

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suppose I want to do define a cheer that
nested inside

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main and you see already here I get a
syntax error

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an that you cannot do this and our lives

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I have already defined H let's define
this gold this K

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an but I still cannot do that am because

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a and now it gives me a proper bar chair

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saying that yeah you cannot have local

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function declaration said i think thats
and something that I do miss

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and C sharp biggest now if you want to
declare

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matter like that yet to lift everything

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to the top level

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what else can we say about C sharp well
and

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comprehension so in c-sharp when I say
here far

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X's equals and neo

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array and long comment to country for

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5 so here we and haven't array

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excess of values 135 you see this

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full type inference I don't have to
specify any types

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and now i can say var wise equals

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from X in X's where

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X last and for

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and select and X

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times too okay and here you see

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day and comprehension syntax in c-sharp

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it looks a little bit like sequel and

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and that on purpose showed these are
called link comprehension

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but they work exactly the same way as
haskell list comprehension

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talking about a an comprehension ce

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sharper of course also supports the rage

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of higher-order functions that the know
and love

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from Haskell so in this case if we look
at

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efforts type for wise that has type

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I innumerable event and every use
intellisense to show

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and the message there that are available
there we see

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and that there are love Matt

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in here and and sharp

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goals them slightly different then am

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ask all and other languages is Adam map

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sharp and uses

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select and and

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bob up there is a little bit small but
select is said

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the version of mapping it takes a
function and

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binds are flat map a is called

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like many if the look here there's a
select many

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and instead of filter and sharp

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and uses where sup except for this
little of our renaming

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of these methods all the higher-order
functions over collections and even more

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and like group by and

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jawans and are all available

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and in the standard library alright

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should if you want to get sharper or
Visual Basic

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RF sharp dry an

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you can and immediately apply all day

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thinks that you learned in the haskell
part of the course

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and to programming an in

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these dotnet languages thank you and see
you next time