Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge

jeudi 16 décembre 2010

Statejeudi 16 décembre 2010 of the Union

Guillaume Laforge / @glaforge • Groovy Project Manager • Head of Groovy Development at SpringSource • Initiator of the Grails framework • Founder of the Gaelyk toolkit • Co-author of Groovy in Action • Member of «Les Cast Codeurs» podcast • Speaker: JavaOne, QCon, JavaZone, Sun TechDays, Devoxx, The Spring Experience, SpringOne2GX, JAX, Dynamic Language World, IJTC, and more... Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 2jeudi 16 décembre 2010

Agenda •Past – Groovy 1.6 flashback •Present – Groovy 1.7 novelties – A few Groovy 1.7.x refinements •Future – What’s cooking for 1.8 and beyond Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 3jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 150000 100000 50000 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 150000 100000 50000 Groovy 1.5 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 150000 100000 G2One acquisition 50000 Groovy 1.5 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 Groovy 1.6 150000 100000 G2One acquisition 50000 Groovy 1.5 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 Groovy 1.7 Groovy 1.6 150000 100000 G2One acquisition 50000 Groovy 1.5 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

But first... some figures... Downloads Moving Average (year) Groovy downloads per month 200000 Groovy 1.7 Groovy 1.6 8 5 K 150000 100000 50000 Groovy 1.5 1 G2One acquisition 0 déc.-07 févr.-08 avr.-08 juin-08 août-08 oct.-08 janv.-09 mars-09 mai-09 juil.-09 sept.-09 nov.-09 janv.-10 mars-10 mai-10 juil.-10 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4jeudi 16 décembre 2010

looking into the Pastjeudi 16 décembre 2010

Big highlights of Groovy 1.6 • Greater compile-time and runtime performance • Multiple assignments • Optional return for if/else and try/catch/finally • Java 5 annotation definition • AST Transformations • The Grape module and dependency system • Various Swing related improvements • JMX Builder • Metaprogramming additions • JSR-223 scripting engine built-in • Out-of-the-box OSGi support Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 7jeudi 16 décembre 2010

Big highlights of Groovy 1.6 • Greater compile-time and runtime performance • Multiple assignments • Optional return for if/else and try/catch/finally • Java 5 annotation definition • AST Transformations • The Grape module and dependency system • Various Swing related improvements • JMX Builder • Metaprogramming additions • JSR-223 scripting engine built-in • Out-of-the-box OSGi support Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 8jeudi 16 décembre 2010

Multiple assignement // multiple assignment def (a, b) = [1, 2] assert a == 1 && b == 2 // with typed variables def (int c, String d) = [3, "Hi"] assert c == 3 && d == "Hi" def geocode(String place) { [48.8, 2.3] } def lat, lng // assignment to existing variables (lat, lng) = geocode(Paris) // classical variable swaping example (a, b) = [b, a] Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 9jeudi 16 décembre 2010

More optional return // optional return for if statements def m1() { if (true) 1 else 0 } assert m1() == 1 // optional return for try/catch/finally def m2(bool) { try { if (bool) throw new Exception() 1 } catch (any) { 2 } finally { 3 } } assert m2(true) == 2 && m2(false) == 1 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 10jeudi 16 décembre 2010

AST Transformation (1/2) • Groovy 1.6 introduced AST Transformations – AST: Abstract Syntax Tree • Ability to change what’s being compiled by the Groovy compiler... at compile time –No runtime impact! – Change the semantics of your programs! Even hijack the Groovy syntax! – Implementing recurring patterns in your code base – Remove boiler-plate code • Two kinds: global and local – triggered by annotations Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 11jeudi 16 décembre 2010

AST Transformations (2/2) • Transformations introduced in 1.6 – @Singleton – @Immutable, @Lazy, @Delegate – @Newify – @Category, @Mixin – @PackageScope – Swing’s @Bindable and @Vetoable – Grape’s own @Grab Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 12jeudi 16 décembre 2010

@Immutable • To properly implement immutable classes – No mutations — state musn’t change – Private final fields – Defensive copying of mutable components – Proper equals() / hashCode() / toString() for comparisons or as keys in maps @Immutable class Coordinates { Double lat, lng } def c1 = new Coordinates(lat: 48.8, lng: 2.5) def c2 = new Coordinates(48.8, 2.5) assert c1 == c2 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 13jeudi 16 décembre 2010

Grab a grape! • Simple distribution and sharing of Groovy scripts • Dependencies stored locally – Can even use your own local repositories @Grab(group = org.mortbay.jetty, module = jetty‐embedded, version = 6.1.0) def startServer() { def srv = new Server(8080) SIONS) def ctx = new Context(srv , "/", SES ctx.resourceBase = "." ovy") ctx.addServlet(GroovyServlet, "*.gro srv.start() } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 14jeudi 16 décembre 2010

into the Present...jeudi 16 décembre 2010

Big highlights of Groovy 1.7 • Anonymous Inner Classes and Nested Classes • Annotations anywhere • Grape improvements • Power Asserts • AST Viewer • AST Builder • Customize the Groovy Truth! • Rewrite of the GroovyScriptEngine • Groovy Console improvements • SQL support refinements Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 16jeudi 16 décembre 2010

Big highlights of Groovy 1.7 • Anonymous Inner Classes and Nested Classes • Annotations anywhere • Grape improvements • Power Asserts • AST Viewer • AST Builder • Customize the Groovy Truth! • Rewrite of the GroovyScriptEngine • Groovy Console improvements • SQL support refinements Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 17jeudi 16 décembre 2010

AIC and NC • Anonymous Inner Classes and Nested Classes Fo rJ ava ’n p aste c opy atib ility co mp sak e :-) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 18jeudi 16 décembre 2010

Annonymous Inner Classes bo olean called = false Timer ti mer = new Timer() timer.schedule(n ew TimerTask() { void run() { called = true } }, 0) sleep 100 assert called Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 19jeudi 16 décembre 2010

Annonymous Inner Classes bo olean called = false Timer ti mer = new Timer() timer.schedule(n ew TimerTask() { void run() { called = true } { called = true } }, 0) as TimerTask sleep 100 assert called Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 19jeudi 16 décembre 2010

Nested Classes class Environment { static class Production extends Environment {} static class Development extends Environment {} } new Environment.Production() Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 20jeudi 16 décembre 2010

Anotations almost anywhere • You can put annotations – on imports – on packages – on variable declarations • Examples with @Grab following... Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 21jeudi 16 décembre 2010

Grape improvements (1/4) • @Grab on import @Grab(group = net.sf.json‐lib, module = json‐lib, version = 2.3, classifier = jdk15) import net.sf.json.groovy.* assert new JsonSlurper().parseText( new JsonGroovyBuilder().json { book(title: "Groovy in Action", author: "Dierk König et al") }.toString ()).book.title == "Groovy in Action" Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 22jeudi 16 décembre 2010

Grape improvements (2/4) • Shorter module / artifact / version parameter – Example of an annotation on a variable declaration @Grab(net.sf.json‐lib:json‐lib:2.3:jdk15) () def builder = new net.sf.json.groovy.JsonGroovyBuilder def books = builder.books { book(title: "Groovy in Action", author: "Dierk Koenig") } assert books.toString() == {"books":{"book":{"title":"Groovy in Action", + "author":"Dierk Koenig"}}} Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 23jeudi 16 décembre 2010

Grape improvements (3/4) • Groovy 1.7 introduced Grab resolver – For when you need to specify a specific repository for a given dependency @GrabResolver( name = restlet.org, root = http://maven.restlet.org) @Grab(org.restlet:org.restlet:1.1.6) import org.restlet.Restlet Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 24jeudi 16 décembre 2010

Power Asserts (1/2) • Much better assert statement! – Invented and developed in the Spock framework • Given this script... def energy = 7200 * 10**15 + 1 def mass = 80 def celerity = 300000000 assert energy == mass * celerity ** 2 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 25jeudi 16 décembre 2010

Power Asserts (2/2) • You’ll get a more comprehensible output Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 26jeudi 16 décembre 2010

Easier AST Transformations • AST Transformations are a very powerful feature • But are still rather hard to develop – Need to know the AST API closely • To help with authoring your own transformations, we’ve introduced – the AST Viewer in the Groovy Console – the AST Builder Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 27jeudi 16 décembre 2010

AST Builder // Ability to build AST parts // ‐‐> from a String new AstBui lder().buildFromString( "Hello" ) // ‐‐> from code new AstBuilder().buildFromCode { "Hello" } // ‐‐> from a specification { List<ASTNo de> nodes = new AstBuilder().buildFromSpec block { returnStatement { constant "Hello" } } } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 29jeudi 16 décembre 2010

Customize the Groovy Truth! • Ability to customize the truth by implementing a boolean asBoolean() method class Predicate { boolean value boolean asBoolean() { value } } def tr uePred = new Predicate(value: true) def fals ePred = new Predicate(value: false) assert truePred && !falsePred Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 30jeudi 16 décembre 2010

Groovy 1.7.x changes • Since Groovy 1.7.0... Groovy 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5 and 1.7.6 have been released already! • Here’s what’s new! Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 31jeudi 16 décembre 2010

Grape improvements (4/4) • Groovy 1.7.5 even further shrinks the grab resolver definition: @Gra bResolver(http://maven.restlet.org) @Grab(org.restlet:org.restlet:1.1.6) import org.restlet.Restlet Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 32jeudi 16 décembre 2010

Map improvements (1/2) // map auto‐vification def m = [:].withDefault { key ‐> "Default" } assert m[z] == "Default" assert m[a] == "Default" // default sort, sort with a comparator m.sort() m.sort({ a, b ‐> a <=> b } as Comparator) // max{} and min{} assert [a: 1, b: 2].max{ it.value }.value == 2 Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 33jeudi 16 décembre 2010

Map improvements (2/2) // before Map#withDefault() def words = "one two two three three three".split() def freq = [:] words.each { if (it in freq) freq[it] += 1 else freq[it] = 1 } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 34jeudi 16 décembre 2010

Map improvements (2/2) // after Map#withDefault() def words = "one two two three three three".split() def freq = [:].withDefault { k ‐> 0 } words.each { freq[it] += 1 } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 35jeudi 16 décembre 2010

XML back to String • Ability to retrieve the XML string from a node from an XmlSlurper GPathResult def xml = """ <books> <book isbn="12345">Groovy in Action</book> </books> """ def root = new XmlSlurper().parseText(xml) def someNode = root.book def bu ilder = new StreamingMarkupBuilder() assert build er.bindNode(someNode).toString() == "<book isbn=12345>Groovy in Action</book>" Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 36jeudi 16 décembre 2010

Currying improvements // right currying def divide = { a, b ‐> a / b } def halver = divide.rcurry(2) assert halver(8) == 4 // currying n‐th parameter def jo inWithSeparator = { one, sep, two ‐> one + sep + two } def joinWithComma = jo inWithSeparator.ncurry(1, , ) assert joinWithComma(a, b) == a, b Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 37jeudi 16 décembre 2010

Date improvements im port static java.util.Calendar.* // convert to calendar def cal = new Date().toCalendar() // update a date (or a calendar) cal.set(year: cal[YEAR] + 1) cal[MONTH] = MARCH // create a ne w date (or a calendar) from one def nextYear = c al.updated(year: cal[YEAR] + 1) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 38jeudi 16 décembre 2010

New String methods println """ println """ def method() { |def method() { return bar | return bar } |} """.stripIndent() """.stripMargin(|) // string "translation" (UNIX tr) assert hello.tr(z‐a, Z‐A) == HELLO WAAAA! asse rt Hello World!.tr(a‐z, A) == HAAAA 2d! assert Hell o World!.tr(lloo, 1234) == He224 W4r // capitalize the first letter assert h.capitalize() == H assert hello.capitalize() == Hello rld asse rt hello world.capitalize() == Hello wo mmand) // tab/space (un)expansion (UNIX expand co 7 8 assert 1234567t8t .expand() == 123456 assert x .unexpand() == xt Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 39jeudi 16 décembre 2010

Map supports isCase() def m = [a: 1, b: 2] def val = a switch (val) { case m: "key in map"; break // equival ent to // case { val in m }: ... default: "not in map" } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 40jeudi 16 décembre 2010

(G)String to Enum coercion enum Color { red, green, blue } // coercion with as def r = "red" as Color // implicit coercion Color b = "blue" // with GStrings too def g = "${green}" as Color Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 41jeudi 16 décembre 2010

...and beyond!jeudi 16 décembre 2010

Groovy 1.8 & beyond • Still subject to discussion • Always evolving roadmap • Things may change! Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 43jeudi 16 décembre 2010

What’s cooking?jeudi 16 décembre 2010

What we’re working on • More runtime performance improvements • Closures – annotation parameters composition, memoization, and trampoline • Native JSON support – builder and parser • New AST transformations • Gradle build • Modularizing Groovy • Align with JDK 7 / Java 7 / Project Coin • Enhanced DSL support Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 45jeudi 16 décembre 2010

Gjeudi 16 décembre 2010

An example, with Fibonacci • Known example of worst case performance for Groovy Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 48jeudi 16 décembre 2010

An example, with Fibonacci • Known example of worst case performance for Groovy • Groovy 1.7.5 vs Java – 25131ms / 1110ms –22x slower! Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 48jeudi 16 décembre 2010

An example, with Fibonacci • Known example of worst case performance for Groovy • Groovy 1.7.5 vs Java – 25131ms / 1110ms –22x slower! • Groovy 1.8-beta-3 vs Java – 1871ms / 1110ms –only 68% slower Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 48jeudi 16 décembre 2010

An example, with Fibonacci • Known example of worst case performance for Groovy 13 x • Groovy 1.7.5 vs Java – 25131ms / 1110ms –22x slower! • Groovy 1.8-beta-3 vs Java – 1871ms / 1110ms –only 68% slower Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 48jeudi 16 décembre 2010

Optimizations for int • Currently, the optimizations cover most of native operations on primitive ints – Be careful, your mileage may vary • To come next – optimizations for doubles – improving array accesses – then other primitives optimizations – and mixed cases of primitives Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 49jeudi 16 décembre 2010

Closure annotation parameters • Groovy 1.5 brought Java 5 annotations • What if... we could go beyond what Java offered? – In 1.7, we can put annotations on packages, imports and variable declarations – But annotations are still limited in terms of parameters they allow • Here comes closure annotation parameters! – Groovy 1.8 will give us the ability to access annotation with closure parameters at runtime Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 50jeudi 16 décembre 2010

GContracts • Closures are already allowed in the Groovy 1.7 Antlr grammar – André Steingreß created GContracts, a «design by contract» module // a class invariant @Invar iant({ name.size() > 0 && age > ageLimit() }) class Person { String name; int age } // a method pre‐condition @Requires({ message != null }) void greet(String message) { ... } // a method post‐condition @Ensures({ returnResult % 2 == 0 }) int evenResult() { ... } Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 51jeudi 16 décembre 2010

Closure composition • Functional flavor! def plus2 = { it + 2 } def times3 = { it * 3 } def composed1 = plus2 << times3 assert composed1(3) == 11 assert composed1(4) == plus2(times3(4)) def composed2 = times3 << plus2 assert composed2(3) == 15 assert composed2(5) == times3(plus2(5)) // reverse composition assert composed1(3) == (times3 >> plus2)(3) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 52jeudi 16 décembre 2010

Closure memoization • Memoization: remember the outcome of previous (ideally side-effect free) invocations def c = { a, b ‐> sleep 1000; a + b }.memoize() assert c(1, 2) == 3 // after 1000ms assert c(1, 2) == 3 // return immediately // other forms: // at least 10 invocations cached def cAtLeast = { ... }.memoizeAtLeast(10) // at most 10 invocations cached def cAtMost = { ... }.memoizeAtMost(10) // between 10 and 20 invocations cached def cAtLeast = { ... }.memoizeBetween(10, 20) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 53jeudi 16 décembre 2010

Closure trampoline • No more infamous StackOvervlow errors for deeply recursive algorithms – if you use closure trampolines explicitely def fact fact = { int n, BigInteger accu ‐> n > 1 ? fact.trampoline(n ‐ 1, n * accu) : accu }.trampoline() def factorial = { int n ‐> fact(n, 1G) } assert factorial(1) == 1 assert factorial(3) == 6 assert factorial(1000) == 402387260077... Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 54jeudi 16 décembre 2010

New AST xforms (1/2) • Many new transformations coming up for removing even more boiler plate code @Log inject a logger in your classes @Field creates a field in your scripts @PackageScope improvements (methods & fields) @Synchronized providing safer synchronization semantics @InheritConstructor ex. when extending Exception @IndexedProperties JavaBeans indexed property support @AutoClone automatic cloning of your beans @AutoExternalizable automatic externalization of your beans Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 55jeudi 16 décembre 2010

New AST xforms (2/2) @ThreadInterrupt makes a script interruptible @TimedInterrupt interrupt after a period of time @ConditionalInterrupt interrupt with a custom condition @Canonical adds equals, hashCode, toString, ctor - @EqualsAndHashCode just equals and hashCode - @ToString just toString - @TupleConstructor adds a «tuple» constructor Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 56jeudi 16 décembre 2010

Java 7 / 8 / Project Coin • Alignment with JDK 7 will come in Groovy 1.9 • JSR-292 InvokeDynamic • Simple Closures (8) • Proposals from Project Coin – Strings in switch (7) – Automatic Resource Management (7) – Improved generics type inference (diamond <>) (7) – Simplified varargs method invocation (7) – Better integral literals (7) – Language support for collections (8?) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 57jeudi 16 décembre 2010

Improved DSL support • GEP-3: an extended command expression DSL – Groovy Extension Proposal #3 • Command expressions – basically top-level statements without parens – combine named and non-named arguments in the mix •for nicer Domain-Specific Languages – (methodName arguments)* Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 58jeudi 16 décembre 2010

Before GEP-3 • The idea: extend command-expressions, beyond top-level statements, for chained method calls • Before send("Hello").to("Graeme") check(that: margherita).tastes(good) sell(100.shares).of(MSFT) take(2.pills).of(chloroquinine).after(6.hours) wait(10.minutes).and(execute { }) blend(red, green).of(acrylic) Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 59jeudi 16 décembre 2010

With GEP-3 • The idea: extend command-expressions, beyond top-level statements, for chained method calls • After send "Hello" to "Graeme" check that: margherita tastes good sell 100.shares of MSFT take 2.pills of chloroquinine after 6.hours wait 10.minutes and execute { } blend red, green of acrylic Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 60jeudi 16 décembre 2010

With GEP-3 • The idea: extend command-expressions, beyond top-level statements, for chained method calls • After Less & co pare send "Hello" to "Graeme" check that: margherita tastes good mm ns sell 100.shares of MSFT as take 2.pills of chloroquinine after 6.hours wait 10.minutes and execute { } blend red, green of acrylic Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 60jeudi 16 décembre 2010

The pattern • A repetition of – method name – arguments (mix of named and normal) check that: margherita tastes good method method named parameter parameter name name Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 61jeudi 16 décembre 2010

Summary • No need to wait for Java 7, 8, 9... – closures, properties, interpolated strings, extended annotations, metaprogramming, [YOU NAME IT]... Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 62jeudi 16 décembre 2010

Summary • No need to wait for Java 7, 8, 9... – closures, properties, interpolated strings, extended annotations, metaprogramming, [YOU NAME IT]... ’s s till Gro ovy novat ive in 20 03! si nce Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 62jeudi 16 décembre 2010

Picture credits Myself http://www.flickr.com/photos/romainguy/783719255/sizes/l/in/photostream/ Big hat http://cdn.plussizecostumesupercenter.com/csc_inc/images/items/343x432/47703.jpg RIP http://gipsydan.files.wordpress.com/2009/11/rip.jpg House / past: http://www.flickr.com/photos/jasonepowell/3680030831/sizes/o/ Present clock: http://www.flickr.com/photos/38629278@N04/3784344944/sizes/o/ Future: http://www.flickr.com/photos/befuddledsenses/2904000882/sizes/l/ Cooking: http://www.flickr.com/photos/eole/449958332/sizes/l/ Snail http://www.freakingnews.com/images/app_images/snail-0.jpg Usein bolt record http://www.phombo.com/sports/usain-bolt-beijing-2008-olympics/17450/full/popular/ Fibonacci figure http://cnx.org/content/m22060/latest/graphics1.jpg Fibonacci face http://www.robinkelly.co.nz/site/acupil/images/lfib.jpg Puzzle: http://www.everystockphoto.com/photo.php?imageId=263521 Light bulb: https://newsline.llnl.gov/retooling/mar/03.28.08_images/lightBulb.png Check mark: http://www.lnl.infn.it/~epics/WikiDumps/localhost/600px-symbol_ok.svg.png Puzzle: http://www.everystockphoto.com/photo.php?imageId=263521 Light bulb: https://newsline.llnl.gov/retooling/mar/03.28.08_images/lightBulb.png Green leaf: http://www.flickr.com/photos/epsos/3384297473/ Trafic light: http://rihancompany.com/var/243/35581-Traffic%20light%20drawing.jpg Butt kick: http://www.brentcsutoras.com/wp-content/uploads/2009/12/kick-ass-1.jpg Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 64jeudi 16 décembre 2010

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Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge

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Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge Presentation Transcript