F# Path to Relaxation

7/25/2019 F# Path to Relaxation

http://slidepdf.com/reader/full/f-path-to-relaxation 1/88

| Basel

The F# Path toRelaxationLanguage Design, Tools, Platforms, Community, Ecosystem,Exosystem, Oenness, Cross!latform, "

Don yme, F# Community Contri$utor



% &entle troll Through the Lan' of LaDesign an' Deli(ery



% starting osition")

The great 'isutes of comuter scishoul' $e struggle' *ith

They are chances to ma+e a $etter, smore relaxe' *orl' as much as cre

oosing cams





-ou can of course ta+e this too f



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Functional 1nter



Then 23445/

Functional languages *ere isolate', n

interoera$le, using their o*n 67s) 1ntstan'ar's li+e C!calls, CO7, CORB%, 07L

mess for language!integration)



The F# %roach 2also cala, *ift

Em$race in'ustry!stan'ar' runtime layers, an'

them) 9ee exosystem at an aroriate 'istanc*ith en'!to!en' intero in min') Comromise

nee'e')



Relaxation %chie(e', 344: ;

; To'ay<s FP languages are immensely intero

*hile staying true to FP rinciles); F# tye ro(i'ers raise intero to a comlet

le(el

= ome tensions remain > not all functional techni?ues are easily imlementestan'ar' 67s

Functional



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Enterrise

Oens



TL@DR > Ahere *e are no*



1n one year, *e<(e come along *ay



The F# Comiler > 544 Pull Re?uesrising

Ahere to Contri$ute

ee fshar)githu$)io

http://fsharp.github.io/

http://fsharp.github.io/



The F# Language Design Proc

fslang)user(oice)com

http://fslang.uservoice.com/

http://fslang.uservoice.com/



F# )4

; True shift to cross!latform oenengineering

; Long laun'ry list of language items; ormalie' core li$rary; Tye ro(i'ers more o*erful

; Better 'e$ugging, tooling, erformance



The F# Comiler er(ice

fshar)githu$)ioHFhar)Comiler)er(ic

http://fsharp.github.io/FSharp.Compiler.Service





Relaxation %chie(e' ;

Enterrise Iuality Oenness

Community Tooling Ecosystem E(olution PathJ

&oo'ness

Enterrise





Functional O$Kec



Then 23445/

1n the MM4s functional languages *ere hisanti!OO

E(en to'ay any mention of o$Kects gi(es some eoNurrgghhh" reaction)

7o'ern Comiler 1mlementation *ith tan'ar' 7L ! CO$Kect Oriente' Programming



F# ! O$Kects Functional

type Vector2D (dx:double, dy:double) =

let d2 = dx*dx+dy*dy

member v.DX = dx

member v.DY = dy

member v.Lengt = !"rt d2

member v.#c$le(%) = Vector2D (dx*%, dy*%)

Inputs to objeconstructio

Exported prope

Exported met

Object intern

O$K

Constructed Class Types



O$Kects

Object Interface Types

type IObject =&nter'$ce ISimpleObject

$b!tr$ct Prop1 : type $b!tr$ct Meth2 : type -> type

Object Expression

{ ne IObject &t member x.Prop1 = expr

member x.Meth1 args = e

{ ne Object() withmember x.Prop1 = expr

&nter'$ce IObject &t member x.Meth1 args = &nter'$ce Ii!"et &t member x.Meth1 args =

Constructed Class Types

type Object#$pe(args) = let i%ter%&l'&le = expr

let i%ter%&l%ctio% args = expr let mut$ble i%ter%&lSt&te = expr member x.Prop1 = expr member x.Meth2 args = expr



The F# aroach is to em$race o$Kects,them t *ith the exression!oriente' ty

functional ara'igm

esecially for intero an' soft*are engineering ur

$ut not em$race full No$Kect!orientation



Expression-oriented

No null MultipleArgs =Tuples

ClosureandCapture

irst-class!alues

Curr"in

%oid

&unit'

ObjectT"pes

(ubt"ping

)ot-notation

Inheritance

MethodO%erloding

Q

*elati%e)eg

&some t"pne

*elati%el" +race$ul)egradation

&some t"pe annotationsneeded'

Functional

O$ Kects



% l i



%n analysis 2imon Cousins, Energy ector/

5S4,444lines of C# OO

$y oshore team

54,444lines of ro$ust F#, *itarallel more featur

%n alication to e(aluate the re(enue 'ue from Balancing er(ices contracts in the 9 energy in'ustry

htt.HHsimontcousins)aure*e$sites)netH'oes!the!language!you!use!ma+e!a!'ierence!re(isite'H

http://www2.nationalgrid.com/uk/services/balancing-services/


http://simontcousins.azurewebsites.net/does-the-language-you-use-make-a-difference-revisited/











imon Cousins, Energy ector

Uero$ugs in 'eloye' system

NF# is the safe choice for this rany other choice is too ris+y

%n alication to e(aluate the re(enue 'ue from Balancing er(ices contracts in the 9 energy in'ustry

htt.HHsimontcousins)aure*e$sites)netH'oes!the!language!you!use!ma+e!a!'ierence!re(isite'H










Positi(e ynthesis %chie(e'

some limitations remain" an' there is one area in

that<s *orth 'iscussing")

Functional



Circularities an' 7o'ularity in th

2%nalysis $y cott Alaschin an' F# Com



7ixe' OOHFunctional ProgramVas Aon

Lam$'as in C#, Wa(a, C, "%sync mona'ic mo'ality in C#, Wa(ascri

2Vac+/, "

Function tyes in C# Tyecrit



nnecessary Circularities are E(il



nnecessary Circularities are E(il

To the functional rogrammer, it is No$(ious soft*are metho'ology shoul' hel minimie a

re'uce c clic 'e en'encies in ro ram struct

The C# aroach to circularity



The C# aroach to circularity

%ll les in an Nassem$ly are mutually referen

%r$itrary circularity $et*een Ninternal itemsassem$ly

7utually recursi(e Nassem$lies are ossi$le har'

The F# aroach to circularity



The F# aroach to circularity

Li+e Vas+ell an' OCaml, F# has a le or'erin

F# encourages minimiing 'een'encies *ith

Parameteriation the referre' techni?ue

F# o$Kects suort limite' forms of circularitynee'e'

Let<s analyse some C# an' F#



Let s analyse some C# an' F#roKects

Let<s analyse some C# an' F#



Let s analyse some C# an' F#roKects

F# co'e has fe*



le(el 'een'enc







Ahy the 'ierence $etF#



F#

1n C#, there is nothing from creating cycles) 1nha(e to ma+e a secia

a(oi' them)

1n F#, you canXt easily at all)

(pec



(pec

Tic/l



Tic/l

Tic+

7icro



Tic+



1n theory an' in ractice, unmo'erate'

comonent cycles are a 'isaster

Language mechanisms that enforce acyclNgoo'

There are signicant unresol(e' tensions the maKor in'ustrial languages



Pattern

7atching

%$stra

n







Enter F# %cti(e Patterns"

2imilar to cala extractors, 'esigne' at the same time in loose c

%cti(e Patterns in F#



let m l'i&*ect c1 c2 =m &tch c1+c2 w ith , *ect(&r+&i)+ *ect(br+bi)->

re&te*ect(&rbr - &ibi+ &ibr / bi&r)

let (,*ect,) (x:com plex) = (x.*e&l+ x.Im &"i%&r$)let (,Pol&r,) (x:com plex) = (x.M &"%it!e + x.Ph&0e)

T*o (ie*s on comlex nu

let m l'i&Pol&r c1 c2 =m &tch c1+c2 w ith , Pol&r(r1+th1)+Pol&r(r2+th2)->

re&tePol&r(r1r2+ th1/ th2)

let m l'i&*ect (*ect(&r+&i)) (*ect(br+bi)) = re&te*ect(&rbr - &ibi+ &ibr / bi&r)let m l'i&Pol&r (Pol&r(r1+th1)) (Pol&r(r2+th2)) = re&tePol&r(r1r2+ th1/ th2)

These tags areNacti(e recognier

la$els

These tags areNacti(e recognier

la$els

The *hole functionis an Nacti(erecognier)

The *hole functionis an Nacti(erecognier)

They are Kust or'inafunctions *ith N$ana

names

They are Kust or'inafunctions *ith N$ana

names

The use of acti(erecognier la$els

imlicitly selectan' aly thefunction

The use of acti(erecognier la$els

imlicitly selectan' aly thefunction

(,*ect,)(,Pol&r,)



mo!le &0icP&tter%0 =

let (,'&l e, ,) (e Sh&rp3 pr)



let (,'&le,,) (e:Sh&rp3xpr) = ...

let (,o%0t,,) (e:Sh&rp3xpr) = ...

let (,#$pe4&mb!&,,) (e:Sh&rp3xpr) = ...

let (,4&mb!&,,) (e:Sh&rp3xpr) = ...

let (,5pplic&tio%,,) (e:Sh&rp3xpr) = ...

let (,I6#he%3l0e,,) (e:Sh&rp3xpr) = ...

let (,4et,,) (e:Sh&rp3xpr) = ...

let (,4et*ec,,) (e:Sh&rp3xpr) = ...

let (,7ew*ecor!,,) (e:Sh&rp3xpr) = ...

let (,7ew8%io%&0e,,) (e:Sh&rp3xpr) = ...

let (,7ew#ple,,) (e:Sh&rp3xpr) = ...

let (,#ple9et,,) (e:Sh&rp3xpr) = ...

let (,I!e%ti6ier7&meS$%t&x,,) (%: Sh&rpS$%t&x7o!e) =



m&tch % with , : I!e%ti6ier7&meS$%t&x &0 t -> Some(t.Sh&rp;i%!()+t.I!e%ti6ier) , -> 7o%e

let (,I!e%ti6ier7&me,,) (%: Sh&rpS$%t&x7o!e) = m&tch %.Sh&rp;i%!() with , S$%t&x;i%!.I!e%ti6ier7&me -> ... , -> 7o%e

let (,<&li6ie!7&meS$%t&x,,) (%: Sh&rpS$%t&x7o!e) = m&tch % with , : <&li6ie!7&meS$%t&x &0 t -> ...

, -> 7o%e

let (,<&li6ie!7&me,,) (%: Sh&rpS$%t&x7o!e) = m&tch %.Sh&rp;i%!() with , S$%t&x;i%!.<&li6ie!7&me -> ... , -> 7o%e

Pattern7atching



Relaxation %chie(e' ;

%n extremely useful mechanism that greatly ex

utility of attern matching in the languag

Don<t lea(e home *ithout them

7atching



Co'e Dat1n one large

comany, GS44eole *or+ on

tooling for this

"an' Seole *

tooling f



Ae are li(ing through ainformation re(olution

The 1nformation Re(olution



3 5 S Z [



Ae nee' to $ring information intlanguage"

%t internet-scale, strongl" tooled, strot"ped

Para'igm Locator



Options

• ma/e staticall" t"ped langmore d"namic

• ma/e d"namicall" t"pedlangs more static

• appl" moderated static

t"ping much more broadl"



htt.HHfshar)githu$)ioHFhar)DataHimages

htt.HHfshar)githu$)ioHFhar)DataHimage

http://fsharp.github.io/FSharp.Data/images/csv.gif

http://fsharp.github.io/FSharp.Data/images/wb.gif







Enter . T"pe 0ro%iders12

NWust li+e a li$rary

N% 'esign!time comonent that comutes a sace of

metho's on!'eman'"

N%n a'ator $et*een 'ataHser(ices an' the )ET tye s

NOn!'eman', scala$le comile!time ro(ision of tye'enitions"

Theme # ! 7any Data ources, O7 h i



7echanism

t"pes

egoe 1 Light

IL #



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Theme #3 ! Data at 7ultile ca



From E(erything to 1n'i(i'uals

d$t$.llnt&te!

Data criters ne*or+ *ith 'ier

granularities schematiatio

d$t$.utomot&ve.utomob&le odel!

d$t$.utomot&ve.utomob&le odel!.-nd&v&du$l!.or!ce /

"Only a language thatsuorts massi(ely scala$lemeta'ata can oerate at all

these le(els

E(ery staentity c

get a untye

“The idea of integrating interne



information services directly i program's ariable and type space is pr

the most innovative programlanguage idea I!e heard of in a de

# Wim Cor'y, Iu

O(erly +in', $ut thought ro

Co'e



Relaxation %chie(e' ; ;

F# Tye Pro(i'ers ha(e $een a hugely successful featurange of useful alication is enormous) They $ring '

tye' rogramming into synthesis li+e no other featur



0 -

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ync %syn



um$ersum$

*ith



&P CP

htt.HHfshar)orgHuseHgu ;

http://fsharp.org/use/gpu

http://fsharp.org/use/gpu



Ahat<s %hea'

Aell, for me, many areas of tension in Nu

language 'esign ha(e $een resol(e

But there are still some areas that $ug

Distri$



REPLDistri$

n ancal

htt.HHm!$race)net

http://m-brace.net/

http://m-brace.net/



Ro*s Colum

e)g) Trill ! 6LDB ]S

1n ConclusionFunctional

O$Kects ync



Co'e Data

OenEnterris

e "



Documents

F# Path to Relaxation