Codegeneration With Xtend

Code Generation with

Sven Efftinge - itemis

What is it?

Successor to Xpand

Built with

Why ?much faster (as fast as Java)

much better IDE support

generalized set of features

simpler

Code Generation Essentials

Template Expression(aka string concatenation)

same syntax as in Xpand

just an expression

greyspace support!

static typingsimply Java

no pluggable type system

can be emulated withactive annotations

longitude & latitude

higher-order functions

map, filter, flatten, etc.it’s just library!

class TypeProviderExample { def getHourlyData() { data.weather.hourlys } def getTimeWithHighestSwell() { hourlyData.sortBy[swellheightM].head.time } def getAverageWindSpeed() { hourlyData.map[windspeedkmph].reduce[a,b|a+b] / hourlyData.size }}

dynamic dispatch

dynamic dispatch

dynamic dispatch

easily debuggable & extendable

dynamic dispatch

def generate(ETypedElement e) { switch e { EAttribute : ''' attribute ''' EReference case e.isContainment: ''' containment reference ''' EReference : ''' reference ''' EOperation : ''' operation ''' default : throw new IllegalArgumentException("not handled : "+e) } }

dispatch over type and state

first come first serve

modularization

AOP?

Dependency Injection!

class MainGenerator { @Inject extension EcoreGen ecoreGenerator def doGenerate(EClass it) ''' class «name» { «FOR f : EStructuralFeatures» «f.generate» «ENDFOR» } '''}

class EcoreGen { def dispatch generate(EAttribute attribute) ''' generate attribute ''' def dispatch generate(EReference reference) ''' generate reference ''' def dispatch generate(EOperation operation) ''' generate operation '''}

declare the dependency

class MySpecialEcoreGen extends EcoreGen { override dispatch generate(EAttribute attribute) ''' special EAttribute ''' def dispatch generate(EParameter param) ''' parameter '''}

class CustomizedGenerator { def static void main(String[] args) { val injector = Guice::createInjector [ bind(typeof(EcoreGen)).to(typeof(MySpecialEcoreGen)) ] val mainGenerator = injector.getInstance(typeof(MainGenerator)) mainGenerator.doGenerate(EcorePackage::eINSTANCE.EClass) }}

Extend the class you want to modify

Use Guice to wire up the generator

content assistsyntax coloring

quick assist outline

rename refactoring

formating

call hierarchytype hierarchy

extract method

debugging

etc...

IDE Support

But why always a DSL?

MyBean

String value

class

MyBeanString value

class {

}

@Observable

future work

tooling via librarymore macro supportembedded languages

snappiness!

Thank you!

@svenefftinge / @xtext / @xtendlang (c) 2013 by