Dev Day 2019: Mike Sperber – Software Design für die Seele

Software-Design
für die Seele
Michael Sperber
@sperbsen
vorbereitet mit:
Nicole Rauch
@nicolerauch

• Individualsoftware
• branchenunabhängig
• funktionale Programmierung
• Scala, Clojure, F#, Haskell, OCaml, Erlang, Elixir, Swift
• Schulungen, Coaching
www.active-group.de
funktionale-programmierung.de

Seelenloser Code
package innocent.plugin.adapter;
import org.eclipse.core.runtime.IAdapterFactory;
import org.eclipse.ui.views.properties.IPropertySource;
import innocent.plugin.adapter.model.Todo;
public class TodoAdapterFactory implements IAdapterFactory {
@Override
public Object getAdapter(Object adaptableObject, Class adapterType) {
if (adapterType== IPropertySource.class && adaptableObject instanceof Todo){
return new TodoPropertySource((Todo) adaptableObject);
}
return null;
}
@Override
public Class[] getAdapterList() {
return new Class[] { IPropertySource.class };
}
}

Seelenloser Code
public class NativeQueryInterpreterInitiator implements SessionFactoryServiceInitiator<NativeQueryInterpreter> {
public static final NativeQueryInterpreterInitiator INSTANCE = new NativeQueryInterpreterInitiator();
@Override
public NativeQueryInterpreter initiateService(
SessionFactoryImplementor sessionFactory,
SessionFactoryOptions sessionFactoryOptions,
ServiceRegistryImplementor registry) {
return new NativeQueryInterpreterStandardImpl( sessionFactory );
}
@Override
public NativeQueryInterpreter initiateService(SessionFactoryServiceInitiatorContext context) {
return new NativeQueryInterpreterStandardImpl( context.getSessionFactory() );
}
@Override
public Class<NativeQueryInterpreter> getServiceInitiated() {
return NativeQueryInterpreter.class;
}
}

Seelenloser Code
DRecherche::DRecherche()
{
if(DIMAServerModel::iFulltext)
m_pcoImaObjectBuilder =
(DImaObjectBuilder*) new DFTRechercheBuilder;
else
m_pcoImaObjectBuilder =
(DImaObjectBuilder*) new DRechercheBuilder;
}

Seelenloser Code
void DRecherche::Expand(DData* pcoDestData, DBool bRecursive, DBool bCrossOver)
{
if(!bRecursive) {
//m_pcoData->CleanDataContainer();
if(DIMAServerModel::iFulltext)
((DFTRechercheBuilder*)m_pcoImaObjectBuilder)
->VolltextRecherche(m_pcoData, pcoDestData);
else
((DRechercheBuilder*)m_pcoImaObjectBuilder)
->Recherche(m_pcoData,pcoDestData);
// Flag setzen, damit asynchroner Job nach dem Zuruecksenden
// der Objekte aktiviert wird
m_iAsyncFlag = 1;
} // if bRecursive
}

Marktdaten
Theoretical Basket
Volatility
Google
vol surface
Facebook
vol surface
call Google
1y, ATM
call Google
3m, 200
call Facebook
1y, ATM
call Facebook
5m, 150

Quellen für Marktdaten
class MarketData {
double GetSpot(long sicovam);
double GetVolat(long sicovam,
double maturity,
double strike);
}

Marktdaten-Szenarien
class SpotShiftedMarketData
: public MarketData {
double GetSpot(long sicovam) {
return MarketData::GetSpot(sicovam)
* factor;
}
}

Decorator-Pattern
Source: https://en.wikipedia.org/wiki/Decorator_pattern

Veränderte Marktdaten
class MarketDataDecorator : public MarketData {
MarketData* fMarketData;
MarketDataDecorator(MarketData* marketData)
: fMarketData(marketData) {}
double GetSpot(long sicovam) {
return fMarketData->GetSpot(sicovam);
}
}

Baskets
double SpotShiftedMarketData::GetSpot(long sicovam)
{
return fMarketData->GetSpot(sicovam) * factor;
}
double MarketData::GetSpot(long sicovam) {
return f(GetSpot(basketComponent), ...)
}

double CURiskMatrixMarketData::GetVolat( long code,
double startDate,
double endDate,
double strike,
NSREnums::eVolatilityType volat,
Boolean put,
const CSRMarketData *context) const
{
if (CalledFromAPricingFunctionFromLV) {
double init_vol = 0.0;
const CSRInstrument *instrument = GetCSRInstrument(code);
if(instrument
&& instrument->HasAVolatilityFormula()
&& !DoesTheFirstMarketDataDeriveFromTheSecondOne(this,context))
init_vol = fMarketData->GetVolat(code,startDate,endDate,strike,volat,put,fMarketData);
else
init_vol = fMarketData->GetVolat
(code,startDate,endDate,strike,volat,put,(context)?context:this);
return fabsolute_volat_shift_factor + init_vol;
}
else {
const CSRInstrument *instrument = GetCSRInstrument(code);
double vol = HVBMarketDataDelegator::GetVolat(code,startDate,endDate,strike,volat,put,context);
if(instrument && instrument->HasAVolatilityFormula())
return vol;
return vol + fabsolute_volat_shift_factor;
}
}
Seelenloser Code

Funktionale Programmierung!
1. unveränderliche Daten
2. weniger Kopplung
3. Verifikation

2. weniger Kopplung
3. Verifikation
4. Katamorphismen
5. Bifunktoren

2. weniger Kopplung
3. Verifikation
4. Katamorphismen
5. Bifunktoren
6. Monaden
7. monadische Profunktoren
8. Kleisli arrows

Source: @tpierrain, use case driven

Nach der agilen Revolution
29%
Neue Features
53%
Wartung,
Komplexität
18%
“Professionalisierung”
Fahd Al-Fatish: Software Engineering - the roots, Karlsruher Entwicklertage 2017

Welt aus Objekten
(© Trustees of the British
Museum)

Source: http://bonkersworld.net/object-world (CC)

Imperative Programmierung
jungle.exit(elephant)
room.enter(elephant)
https://www.flickr.com/photos/tomsaint/3266056756

Problem
model view
model’ view’
Veränderung hoffentlich
entsprechend
Veränderung

Alan Kay über OO
Though OOP came from many motivations, two were central.
[...] to find a more flexible version of assignment, and then to
try to eliminate it altogether.
Alan Kay, History of Smalltalk
Communications of the ACM, 1996

OO vs. Zustand
https://www.ntu.edu.sg/home/ehchua/programming/java/J3a_OOPBasics.html

FP FTW!
• einfachere Sprachen
• weniger Komplexität
• höhere Produktivität
• weniger Bugs

FP FTW!
• weniger Bugs
• mächtige Typsysteme
• Testen von Eigenschaften / QuickCheck

FP for the Win!
• weniger Bugs
• mächtige Typsysteme
• Testen von Eigenschaften / QuickCheck
• verlässliches Verhalten
• einfacheres Testen
• weniger Kopplung
• weniger Abhängigkeiten

No Silver Bullet!
Fred Brooks No Silver Bullet — Essence and
Accidents of Software Engineering
IEEE Computer, 1987

Yale-Studie
Hudak, Jones: Haskell vs. Ada vs. C++ vs. Awk vs. ...
An Experiment in Software Prototyping Productivity, Yale University, 1993

Dev Day 2019: Mike Sperber – Software Design für die Seele

Halbleiter-Herstellung
Oxidation
(SiO2)
Diffusing
dopant
Lithography
(pattern)
Etch
(remove)
Deposition
(add)
CMP
(polish)
Repeat for each layerTransistor Layer
Extremely Simplified Process Route

Repräsentation
data Operation =
TrackIn | Process | TrackOut
type Route = [Operation]
r1 = [TrackIn, Process, Process, TrackOut]

Funktionen
routeHead :: Route -> Operation
routeHead [] = ???
routeHead (op:_) = op

Optionale Dinge
data Option a where
Some :: a -> Option a
None :: Option a

Funktionen
routeHead :: Route -> Option Operation
routeHead [] = None
routeHead (op:_) = Some op
routeHead r1 ⇒ Some TrackIn

Funktionen
routeAdvance ::
Route -> Option (Operation, Route)
routeAdvance r1
⇒ Some (TrackIn,
[Process,Process,TrackOut])

Funktionen
routeAdvance ::
routeAdvance [] = None
routeAdvance (op:rest) = Some (op, rest)

Q-Time-Zonen
Pro Route:
• 1000 Operationen
• 50 separate Q-Time-Zonen
Q-Time Zone
Eqp A1
Eqp A1
Eqp A1
Eqp A1
Eqp A1
Eqp B1
Eqp A1
Eqp A1
Eqp C1
Eqp A1
Eqp A1
Eqp D1
Eqp A1
Eqp A1
Eqp X1
Eqp A1
Eqp A1
Eqp Y1
WIP
WIP

Q-Time-Zonen
type Route = [RouteElement]
data RouteElement where
RouteOp ::
Operation -> RouteElement
RouteQTZone ::
Duration -> [Operation] -> RouteElement

Beispiele
r1 = [RouteOp TrackIn,
RouteOp Process, RouteOp Process,
RouteOp TrackOut]
RouteQTZone 5 [Process, Process],
RouteOp TrackOut]

Q-Time-Zonen
RouteOp ::
RouteQTZone ::
Duration -> [RouteElement] -> RouteElement

Beispiele
RouteOp Process, RouteOp Process,
RouteOp TrackOut]
RouteQTZone 5
[RouteOp Process,
RouteOp Process],
RouteOp TrackOut]

Verschachtelte Q-Time-Zonen
RouteQTZone 100
[RouteOp Process,
RouteQTZone 5
[RouteOp Process,
RouteOp Process]]]

Q-Time-Zonen
RouteOp ::
RouteQTZone ::
Duration -> Route -> RouteElement

Funktionen
routeHead :: Route -> Option Operation
routeHead [] = None
routeHead (el:rest) =
case routeElementHead el of
None -> routeHead rest
Some op -> Some op
routeElementHead :: RouteElement -> Option Operation
routeElementHead (RouteOp op) = Some op
routeElementHead (RouteQTZone _ rt) = routeHead rt

Fortschritt
routeAdvance ::
routeAdvance [] = None
routeAdvance (el:rest) =
case el of
RouteOp op -> Some (op, rest)
RouteQTZone d rt -> ???

Q-Time-Zonen in Bearbeitung
RouteOp :: Operation -> RouteElement
RouteQTZone :: Duration -> Route -> RouteElement
RouteQTLimit :: Time -> Route -> RouteElement

Fortschritt
routeAdvance :: Route -> Time -> Option (Operation, Route)
routeAdvance [] t = None
routeAdvance (el:rest) t =
case el of
RouteOp op -> Some (op, rest)
RouteQTZone d rt ->
routeAdvance (RouteQTLimit (t + d) rt : rest) t
RouteQTLimit tl rt ->
case routeAdvance rt t of
None -> routeAdvance rest t
Some (op, rt') ->
Some (op, RouteQTLimit tl rt' : rest)

Unzulässiger Zustand
RouteQTLimit 12
[RouteOp Process,
RouteOp TrackOut]]

Unzulässige Zustände
unmöglich machen
data Route where
Route :: RouteRem -> Route
RouteQTLimit :: Time -> Route -> RouteRem -> Route
type RouteRem = [RouteElement]
RouteOp :: Operation -> RouteElement
RouteQTZone :: Duration -> RouteRem -> RouteElement

+
=https://pixabay.com/en/conversation-dialogue-interview-1262311/
https://commons.wikimedia.org/wiki/File:Bullet_train.jpg

Dev Day 2019: Mike Sperber – Software Design für die Seele

More Related Content

What's hot (20)

Similar to Dev Day 2019: Mike Sperber – Software Design für die Seele (20)

More from DevDay Dresden (20)

Recently uploaded (20)

Dev Day 2019: Mike Sperber – Software Design für die Seele