18. “PATH EXISTS” RESPONSTID
-
One database
containing 1000
persons
-
Max 50 friends
-
Detect if two random
persons are
connected via friends
Antall
personer
Responstid
Relational db
Neo4j
1.000
1.000
2000ms
2ms
Neo4j
1.000.000
2ms
31. GRAMMAR
A “language” can be formally defined as “any system of
formalized symbols, signs, etc. used for communication”
A “grammar” can be defined as a “the set of structural rules
that governs sentences, words, etc. in a natural language”
33. GRAMMAR
Alfred, who loved fishing, bought fish at the store
downtown
(Alfred, (who loved (fishing)), (bought
(fish (at (the store (downtown))))))
34. additionExp
: multiplyExp
( '+' multiplyExp
| '-' multiplyExp
)*
;
multiplyExp
: atomExp
( '*' atomExp
| '/' atomExp
)*
;
atomExp
: Number
| '(' additionExp ')'
;
Number
: ('0'..'9')+
;
An additionExp is defined as a multiplyExp
+ or - a multiplyExp
A multiplyExp is defined as an atomExp *
or / an atomExp
An atomExp is defined as a number or a
parenthesized additionExp
Number is one or more character between
0-9
35. class CalculatorParser extends BaseParser<> {
Rule Expression() {
return Sequence(
Term(),
ZeroOrMore(AnyOf("+-"), Term())
);
}
An expression is a sequence of Term
followed by zero or more “+” or “-” followed
by a Term
Rule Term() {
return Sequence(
Factor(),
ZeroOrMore(AnyOf("*/"), Factor())
);
}
Term is a Factor followed by zero or more
sequences of “*” or “/” followed by a factor
Rule Factor() {
return FirstOf(
Number(),
Sequence('(', Expression(), ')')
);
}
Factor is a number or a parenthesized
expression
Rule Number() {
return OneOrMore(CharRange('0', '9'));
Number is a one or more characters
between 0-9
36. PEG VS CFG
PEGs firstof operator vs CFG’s | operator
PEG does not have a separate tokenizing step
CFG might come across as more powerful, but also more difficult to master
PEG does not allow ambiguity in the grammar
39. class CalculatorParser extends BaseParser<> {
Rule Expression() {
return Sequence(
Term(),
ZeroOrMore(AnyOf("+-"), Term())
);
}
An expression is a sequence of Term
followed by zero or more “+” or “-” followed
by a Term
Rule Term() {
return Sequence(
Factor(),
ZeroOrMore(AnyOf("*/"), Factor())
);
}
Term is a Factor followed by zero or more
sequences of “*” or “/” followed by a factor
Rule Factor() {
return FirstOf(
Number(),
Sequence('(', Expression(), ')')
);
}
Factor is a number or a parenthesized
expression
Rule Number() {
return OneOrMore(CharRange('0', '9'));
Number is a one or more characters
between 0-9
40. I went for a walk downtown
Sequence( “I”, “went”, “for”, “a”, “walk”, “downtown”)
41. went
downtown
I
for a walk
wend
to the city
Sequence(
String(“I”),
FirstOf(“went”, “wend”),
Sequence(“for”, “a”, “walk”),
FirstOf(“downtown”, “to the city”));
44. Rule AnyOf(java.lang.String characters)
Creates a new rule that matches any of
the characters in the given string.
Rule Ch(char c)
Explicitly creates a rule matching the
given character.
Rule CharRange(char cLow, char cHigh)
Creates a rule matching a range of
characters from cLow to cHigh (both
inclusively).
Rule FirstOf(java.lang.Object... rules)
Creates a new rule that successively
tries all of the given subrules and succeeds
when the first one of its subrules matches.
Rule IgnoreCase(char... characters)
Explicitly creates a rule matching the
given string in a case-independent fashion.
Rule NoneOf(char... characters)
Creates a new rule that matches all
characters except the ones in the given char
array and EOI.
Rule NTimes(int repetitions,
java.lang.Object rule)
Creates a new rule that repeatedly
matches a given sub rule a certain fixed
number of times.
45. went
downtown
today
for a walk
today I
walked
to the city
Sequence(
…,
FirstOf(
Sequence(push(“downtown”), “downtown”,
Sequence(push(“city”), “to the city”)));
Jeger Scientist i Bekk hvorjegharjobbetmerellermindresiden 2000.Jeger @olemartinpå twitter, oghvisnoenhar et spørsmålellertilbakemelding under fordragetså ta detgjerne der.
EvolusjonFormel 1Verdensarterogsøkogsøkemotorerså kun påenkeltdokumentermanuellkategorisering
pagerankfragooglealle sider får en pagerankbasertpåinnholdetpåsidenogpagerankpåsidenesomlenker inn
Googles Knowledge Graph, where you can follow relations between different knowledge. Search for Mona Lisa
and you get dynamic information about that picture displayed in the sidebar
Mark Zuckerbergmed facebook graph search vistefacebook at relasjonenevar like viktigsomdataeneomjeg liker fotografi, ogborioslokunneværtioslo, ellerværtfødtioslo, men jeg BOR iosloogdet her visersegåværeveldigkraftig
Facebook Graph Search developed by Lars Rasmussen, the danish dude that created Google Wave.They use a Context Free Grammar, which is translated to a query they run against an index called Unicorn that has a graph-like architecture.
You can also search for combined queries, like people from gothenburg that works as a barista in Oslo, lots of those around :-)
Dettehaddeikkeværtmuliguten en graf-strukturibunnen.Ogdetteer en graf:En grafbestårenkeltforklartavnoderogrelasjoner.En relasjongårfra en node til en annen node. Skalrelasjonengåbeggeveier, må du ha to.Noderkan ha attrubutterogrelasjonerkan ha attributter
Somnavnog alderosvHvis du har data somandrenoderkantenkesegårelateretil, såskiller du den ut via en relasjon
Ogrelasjonenharogsåattributter
If we go back to the monalisa example, some of the attributes presented are in fact attributes, others actually relationships
Fordet vi såkanogsåløses med en relasjonsdatabase.MENStatiskeskjemaer, definereshvordandataeneserutførstTungtåjobbe med mange ogdyperelasjonerogikkeminstytelse
Created in Sweden! :-) By Emil EifremNow have offices in sweden, malaysia with Rickard Øberg, uk with Jim Webber, united states etc. A fast growing company, making some really nice technology. And nobody is paying me a dime to say this, I just love their technology.17 minutter hit
Vi gårtilbaketilgrafen
Det her erogså en grafforsåvidt, dvs en veldiglitengraf.En node med en relasjontil en annen node.
Hvis vi tar detuttrykketogsøkeretterdetidatabasensåfinner man det.Man vilforsåvidtfinneallestederhvor en node errelaterttil en annen
I Matrix erhanikke et godtselskap for Neo, men i Neo4j såer de perlevenner
Ogdetsomerfantastisker at detteer en gyldigi Neo4j
Navngittenoder
Flerenavngittenoder
Relasjonerav en viss type
So… Now we have the database and query language. Now we only need to define some grammar.
A language, norsk,ellerskavlan-svenska, or english
CFG - context free grammar, used byfacebook graph search and many many programming languages. Been used for defining programming languages since the 50sparsing expression grammar, the new kid on the block, defined in 2004
May look a little like LISP
Parboiled is written by a german named Mathias Doenitz. This man has managed to create a user friendly and powerful PEG-parser. Mathias has also created spray.io, a really powerful akka-based REST-module for Scala.Parboiled is the main reason why I went with PEG in my project. Parboiled is easy to understand, and has all the features necessery for
34 minutter hit
whitespaces
ValueStack
ValueStack
Inside your rulesyou might add values to the ValueStack.This is a great way for your rules and actions to communicate, or you can use this to return values from the parsing process.
Vi brukervår cv-databasenaktivt. Når en kundeetterspør en konsulentsomkan neo4j såsøkerselgerengjennomdatabasen. Hviskundenharkravomrelasjoner, andrefagfeltetcsåblirdetkomplekst med fritekst-søk.
Our search is currently a free text search, and a search for Java gives 224 hits. We have 200 developers in our company, including lots of .net developers.
