Building DSLs With Eclipse

Building DSLs with Eclipse Peter Friese, itemis @peterfriese @xtext (c) 2009 Peter Friese. Distributed under the EDL V1.0 - http://www.eclipse.org/org/documents/edl-v10.php More info: http://www.peterfriese.de / http://www.itemis.com

What is a DSL?

Domain

Language

Suppose...

You’d want to core an apple...

... for your kids.

? Right tool for the job?

Your trusty swiss army knife!

Because you can use it for other stuff, too. E.g., opening a bottle of wine.

Suppose...

You’d want to core a few more apples...

... for an apple cake.

Still the best tool for the job?

Better use this one.

and this one:

BUT avoid the unitasker!

... a DSL is ...

A speciﬁc tool for a speciﬁc job

Samples for DSLs

select name, salary from employees where salary > 2000 order by salary

External or Internal

Internal DSLs

Mailer.mail() .to(“you@gmail.com”) .from(“me@gmail.com”) .subject(“Writing DSLs in Java”) .body(“...”) .send();

Simple

Limited

External DSLs

1)Create ANTLR grammar 2)Generate lexer / parser 3)Parser will create parse tree 4)Transform parse tree to semantic model 5)Iterate model 6)Pass model element(s) to template

Flexible

Adaptable

Complicated

Why not use a DSL... ... for building DSLs?

Demo 1

@SuppressWarnings("serial") @Entity @Table(name = "CUSTOMER_INFO") public class CustomerInfo implements Serializable { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "idSeq") @SequenceGenerator(name = "idSeq", sequenceName = "CUST_SEQ", allocationSize = 1) @Column(name = "CUST_ID", nullable = false) private String customerId; public void setCustomerId(String customerId) { this.customerId = customerId; } public String getCustomerId() { return customerId; } @Column(name = "EMAIL", nullable = false, length = 128) private String emailAddress; public String getEmailAddress() { return emailAddress; } public void setEmailAddress(String emailAddress) { String oldValue = emailAddress; this.emailAddress = emailAddress; firePropertyChangedEvent("emailAddress", oldValue, this.emailAddress); }

entity CustomerInfo (id=CUST_ID, sequenceName=CUST_SEQ) { String emailAddress (notNull, length = 128) }

entity CustomerInfo (id=CUST_ID, sequenceName=CUST_SEQ) { String emailAddress (notNull, length = 128) } Bean DAO (POJO)

Underlying Technology

Model G ra m m ar

ar Model m m ra G Generator

ar Model m m ra G Generator Runtime Superclass Subclass Class LL(*) Parser ECore meta model Editor

Grammar (similar to EBNF) grammar org.xtext.example.Entity with org.eclipse.xtext.common.Terminals generate entity "http://www.xtext.org/example/Entity" Model: (types+=Type)*; Type: TypeDef | Entity; TypeDef: "typedef" name=ID ("mapsto" mappedType=JAVAID)?; JAVAID: name=ID("." ID)*; Entity: "entity" name=ID ("extends" superEntity=[Entity])? "{" (attributes+=Attribute)* "}"; Attribute: type=[Type] (many?="*")? name=ID;

grammar org.xtext.example.Entity with org.eclipse.xtext.common.Terminals Meta model inference generate entity "http://www.xtext.org/example/Entity" entity Model: (types+=Type)*; Model Type: TypeDef | Entity; types TypeDef: * Type "typedef" name=ID name: EString ("mapsto" mappedType=JAVAID)?; superEntity JAVAID: name=ID("." ID)*; TypeDef Entity Entity: mappedType attributes "entity" name=ID Attribute ("extends" superEntity=[Entity])? JAVAID name: EString "{" name: EString many: EBoolean (attributes+=Attribute)* "}"; type Attribute: type=[Type] (many?="*")? name=ID;

grammar org.xtext.example.Entity with org.eclipse.xtext.common.Terminals Meta model inference generate entity "http://www.xtext.org/example/Entity" entity Rules -> Classes Model: (types+=Type)*; Model Type: TypeDef | Entity; types TypeDef: * Type "typedef" name=ID name: EString ("mapsto" mappedType=JAVAID)?; superEntity JAVAID: name=ID("." ID)*; TypeDef Entity Entity: mappedType attributes "entity" name=ID Attribute ("extends" superEntity=[Entity])? JAVAID name: EString "{" name: EString many: EBoolean (attributes+=Attribute)* "}"; type Attribute: type=[Type] (many?="*")? name=ID;

grammar org.xtext.example.Entity with org.eclipse.xtext.common.Terminals Meta model inference generate entity "http://www.xtext.org/example/Entity" entity Alternatives -> Hierarchy Model: (types+=Type)*; Model Type: TypeDef | Entity; types TypeDef: * Type "typedef" name=ID name: EString ("mapsto" mappedType=JAVAID)?; superEntity JAVAID: name=ID("." ID)*; TypeDef Entity Entity: mappedType attributes "entity" name=ID Attribute ("extends" superEntity=[Entity])? JAVAID name: EString "{" name: EString many: EBoolean (attributes+=Attribute)* "}"; type Attribute: type=[Type] (many?="*")? name=ID;

grammar org.xtext.example.Entity with org.eclipse.xtext.common.Terminals Meta model inference generate entity "http://www.xtext.org/example/Entity" entity Assignment -> Feature Model: (types+=Type)*; Model Type: TypeDef | Entity; types TypeDef: * Type "typedef" name=ID name: EString ("mapsto" mappedType=JAVAID)?; superEntity JAVAID: name=ID("." ID)*; TypeDef Entity Entity: mappedType attributes "entity" name=ID Attribute ("extends" superEntity=[Entity])? JAVAID name: EString "{" name: EString many: EBoolean (attributes+=Attribute)* "}"; type Attribute: type=[Type] (many?="*")? name=ID;

Demo 2

Poll "Simple poll" question "What's your name?" name question "How do you feel today?" howareyou () "Fine" fine () "Great" great () "Bad" bad () "Not too bad" not2bad question "What's your favourite food?" food [] "Pizza" pizza [] "Pasta" pasta [] "Sushi" sushi [] "Mexican" mexican

Pimp My Write

Tooltips Scoping Outline Label Provider Validation Hyperlinking / Navigation AST Code Formatting Content Assist Folding Quick Fix Datatype Converter Parser Syntax Highlighting

Tooltips Scoping Outline Hyperlinking / Navigation AST Code Formatting Content Assist Folding Quick Fix Datatype Converter Parser Syntax Highlighting

Tooltips Scoping Outline Label Provider Validation Hyperlinking / Navigation AST Code Formatting Content Assist Folding Quick Fix Datatype Converter Parser Syntax Highlighting

Conclusion

Abstraction

Use a DSL to develop your tools

Support Newsgroup Community Forum Professional Support

Heiko Sven Moritz Peter Dennis Jan Patrick Sebastian Michael Knut Behrens Efftinge Eysholdt Friese Hübner Köhnlein Schönbach Zarnekow Clay Wannheden Individual

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Building DSLs With Eclipse

by Peter Friese on Aug 27, 2009

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Building DSLs With Eclipse — Presentation Transcript