This slideshow explains what DSLs are and how to use tools from the Eclipse Modeling Project to create them.

1. 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

7. What is a DSL?

8. Domain

15. Language

18. Suppose...

19. You’d want to core an apple...

20. ... for your kids.

21. ?
Right tool for the job?

22. Your trusty swiss army knife!

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

24. Suppose...

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

26. ... for an apple cake.

27. Still the best tool for the job?

28. Better use this one.

29. and this one:

30. BUT
avoid the unitasker!

31. BUT
avoid the unitasker!

32. ... a DSL is ...

33. A specific tool
for a specific job

34. A specific tool
for a specific job

35. Samples for DSLs

36. SQL

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

38. ANT

39. <project name="MyProject" default="dist" basedir=".">
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="dist" location="dist"/>
<target name="init">
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}"/>
</target>
<target name="dist" depends="compile">
<mkdir dir="${dist}/lib"/>
<jar jarfile="${dist}/lib/MyProject.jar"
basedir="${build}"/>
</target>
<target name="clean">
<delete dir="${build}"/>
<delete dir="${dist}"/>
</target>
</project>

40. <project name="MyProject" default="dist" basedir=".">
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="dist" location="dist"/>
<target name="init">
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}"/>
</target>
<target name="dist" depends="compile">
<mkdir dir="${dist}/lib"/>
<jar jarfile="${dist}/lib/MyProject.jar"
basedir="${build}"/>
</target>
<target name="clean">
<delete dir="${build}"/>
<delete dir="${dist}"/>
</target>
</project>

41. External
or
Internal

42. Internal DSLs

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

44. Simple

45. Limited

46. External DSLs

48. 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

49. Flexible

50. Adaptable

51. Complicated

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

54. Demo 1

56. @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);
}

57. @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);
}

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

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

61. Underlying Technology

62. Model
G
ra
m
m
ar

63. ar
Model
m
m
ra
G
Generator

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

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

66. 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;

67. 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;

68. 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;

69. 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;

70. 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;

71. 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;

72. 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;

73. 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;

74. Demo 2

76. 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

80. Pimp My Write

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

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

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

84. Conclusion

85. Abstraction

86. Use a DSL to develop your tools

87. Support
Newsgroup
Community Forum
Professional Support

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

90. Twitter: @xtext
http://www.xtext.org