Tutorial at EclipseCon 2011 (Santa Clara) Sven Efftinge, Jan Koehnlein, Sebastian Zarnekow

1. Pragmatic DSL Design with
Sven Efftinge (itemis) / Sebastian Zarnekow (itemis) / Jan Köhnlein (itemis)

2. The plan for today :

3. The plan for today :
1. Xtext 2.0
What is Xtext and what’s new in 2.0?
Hands-On : Develop a DSL.

4. The plan for today :
1. Xtext 2.0
What is Xtext and what’s new in 2.0?
Hands-On : Develop a DSL.
2. Xbase
What’s that and why should I care?
Hands-On : Play with it and integrate it in a DSL.

5. The plan for today :
1. Xtext 2.0
What is Xtext and what’s new in 2.0?
Hands-On : Develop a DSL.
2. Xbase
What’s that and why should I care?
Hands-On : Play with it and integrate it in a DSL.
3. Xtend
Yet another language? Are you serious?
Hands-On :Write a codegenerator with Xtend.

6. What is
?

7. Eclipse Project

8. IDE Framework

9. Language Framework

10. (Domain-Specific)
Language Framework

11. Users
Users

15. Eclipse IDE Framework (JFace Text, etc.)

16. Java
Development
Tools
(JDT)
Eclipse IDE Framework (JFace Text, etc.)

17. Java
Development
Tools
(JDT)
Eclipse IDE Framework (JFace Text, etc.)

18. Java
Development
Tools
(JDT)
Eclipse IDE Framework (JFace Text, etc.) Eclipse Modeling Framework (EMF)

19. Java
Development
Tools
(JDT)
Antlr Parser
Generator
Eclipse IDE Framework (JFace Text, etc.) Eclipse Modeling Framework (EMF)

20. is Highly Adaptable

21. Advanced Language-Specific Editing Features
by Default

22. Advanced Language-Specific Editing Features
by Default
Syntax Coloring

23. Advanced Language-Specific Editing Features
by Default
Syntax Coloring
Wizards

24. Advanced Language-Specific Editing Features
by Default
Content Assist
Syntax Coloring
Wizards

25. Advanced Language-Specific Editing Features
by Default
Content Assist
Syntax Coloring
Code Folding
Wizards

26. Advanced Language-Specific Editing Features
by Default
Content Assist
Find References
Syntax Coloring
Code Folding
Wizards

27. Advanced Language-Specific Editing Features
by Default
Global Indexing
Content Assist
Find References
Syntax Coloring
Code Folding
Wizards

28. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist
Find References
Syntax Coloring
Code Folding
Wizards

29. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist
Find References
Syntax Coloring
Code Folding
Wizards Bracket Matching

30. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist
Find References
Syntax Coloring
Auto Editing
Code Folding
Wizards Bracket Matching

31. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist
Find References
Syntax Coloring
Incremental Builders
Auto Editing
Code Folding
Wizards Bracket Matching

32. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist Outline View
Find References
Syntax Coloring
Incremental Builders
Auto Editing
Code Folding
Wizards Bracket Matching

33. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Global Indexing
Content Assist Outline View
Find References
Incremental Builders
Validation Syntax Coloring
Auto Editing
Code Folding
Wizards Bracket Matching

34. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Template Proposals
Global Indexing
Content Assist Outline View
Find References
Incremental Builders
Validation Syntax Coloring
Auto Editing
Code Folding
Wizards Bracket Matching

35. Advanced Language-Specific Editing Features
by Default
Go To Declaration
Template Proposals
Global Indexing
Content Assist Outline View
Quick Fixes
Find References
Incremental Builders
Validation Syntax Coloring
Auto Editing
Code Folding
Wizards Bracket Matching

36. Advanced Language-Specific Editing Features
by Default
Refactoring Go To Declaration
Template Proposals
Global Indexing
Content Assist Outline View
Quick Fixes
Find References
Incremental Builders
Validation Syntax Coloring
Auto Editing
Code Folding
Wizards Bracket Matching

37. Advanced Language-Specific Editing Features
by Default
Refactoring Go To Declaration
Template Proposals
Global Indexing
Content Assist Outline View
Quick Fixes
Find References
Incremental Builders
Validation Syntax Coloring
Rich Hovers Auto Editing
Code Folding
Wizards Bracket Matching

38. ... but there is a problem
with external DSLs

39. What about
Expressions?

41. Expressions are
complicated !

43. Protected Regions

44. Protected Regions
• generated and manually written code mixed
up

45. Protected Regions
• generated and manually written code mixed
up
• manual deletion of artifacts

46. Protected Regions
• generated and manually written code mixed
up
• manual deletion of artifacts
• platform dependent information

47. Protected Regions
• generated and manually written code mixed
up
• manual deletion of artifacts
• platform dependent information
• information is spreaded!

48. Generation Gap Pattern

49. Generation Gap Pattern
technically required type hierarchies

50. Generation Gap Pattern
technically required type hierarchies
additional complexity

51. Generation Gap Pattern
technically required type hierarchies
additional complexity
platform dependent information

52. Generation Gap Pattern
technically required type hierarchies
additional complexity
platform dependent information
information spreaded!

53. Black box
target language literals

54. Black box
target language literals
• bound to target platform

55. Black box
target language literals
• bound to target platform
• no option for MDA friends

56. Black box
target language literals
• bound to target platform
• no option for MDA friends
• no tooling!

57. Black box
target language literals
• bound to target platform
• no option for MDA friends
• no tooling!
• long turnarounds!

58. base

59. base
Modern Expression Language

60. base
Modern Expression Language
JVM-Integration

61. base
Modern Expression Language
JVM-Integration
Statically Typed

62. base
Modern Expression Language
JVM-Integration
Statically Typed
Highly Reusable

63. Your Language
o.e.xtext.common.Terminals
EMF

64. Your Language
common.Types
o.e.xtext.common.Terminals
JDT JVM EMF

65. Your Language
Xbase Ecore
Xbase Grammar
common.Types
o.e.xtext.common.Terminals
JDT JVM EMF

66. @Override
protected IScope createLocalVarScope(~) {
if (context instanceof Operation) {
IScope actualScope =
super.createLocalVarScope(~);
Operation operation = (Operation) context;
return createScope(operation.getParams(),
actualScope);
}
return super.createLocalVarScope(~);
}

67. Using Xbase

68. Using Xbase
Mixin the Grammar

69. Using Xbase
Mixin the Grammar
JVM Model Inference

70. Using Xbase
Mixin the Grammar
JVM Model Inference
Scoping

71. Using Xbase
Mixin the Grammar
JVM Model Inference
Scoping
Type System

72. Using Xbase
Mixin the Grammar
JVM Model Inference
Scoping
Type System
Compiler / Interpreter

73. A DSL for Generating Code

74. Model Code
Code
Generator

75. Model Code
package base;
public class Address {
private String street;
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
private String city;
Code
public String getCity() {
return city;
Generator
}
public void setCity(String city) {
this.city = city;
}
private String state;
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
private String postalCode;
public String getPostalCode() {
return postalCode;
}
public void setPostalCode(String postalCode) {
this.postalCode = postalCode;
}
}

76. BUT I CAN
DO THAT IN

78. package example.codegen;
import org.eclipse.xtext.common.types.JvmFormalParameter;
import org.eclipse.xtext.common.types.JvmTypeReference;
import org.eclipse.xtext.example.domainmodel.domainmodel.Entity;
import org.eclipse.xtext.example.domainmodel.domainmodel.Feature;
import org.eclipse.xtext.example.domainmodel.domainmodel.Operation;
import org.eclipse.xtext.example.domainmodel.domainmodel.Property;
public class JavaGenerator {
public String compile(Entity e) {
StringBuilder b = new StringBuilder();
b.append("package " + packageName(e) + "n");
b.append("n");
b.append("/**n");
b.append(" * Automatically generated. Direct modification is futile.n");
b.append(" */n");
b.append("public class ").append(e.getName());
if(e.getSuperType() != null) {
b.append(" extends ").append(compile(e.getSuperType()));
}
b.append(" {n");
for(Feature f: e.getFeatures()) {
if(f instanceof Property)
feature((Property)f);
else if(f instanceof Operation)
feature((Operation)f);
}
b.append("}n");
return b.toString();

79. package example.codegen;
import org.eclipse.xtext.common.types.JvmFormalParameter;
import org.eclipse.xtext.common.types.JvmTypeReference;
import org.eclipse.xtext.example.domainmodel.domainmodel.Entity;
import org.eclipse.xtext.example.domainmodel.domainmodel.Feature;
import org.eclipse.xtext.example.domainmodel.domainmodel.Operation;
import org.eclipse.xtext.example.domainmodel.domainmodel.Property;
public class JavaGenerator { No Multiline
public String compile(Entity e) {
StringBuilder b = new StringBuilder();
String Literals
b.append("package " + packageName(e) + "n");
b.append("n");
b.append("/**n");
b.append(" * Automatically generated. Direct modification is futile.n");
b.append(" */n");
b.append("public class ").append(e.getName());
if(e.getSuperType() != null) {
b.append(" extends ").append(compile(e.getSuperType()));
}
b.append(" {n");
for(Feature f: e.getFeatures()) {
if(f instanceof Property)
feature((Property)f);
else if(f instanceof Operation)
feature((Operation)f);
}
b.append("}n");
return b.toString();

80. public String compile(Entity e) {
StringBuilder b = new StringBuilder();
b.append("package " + packageName(e) + "n");
b.append("n");
b.append("/**n");
b.append(" * Automatically generated. Direct modification is futile.n");
b.append(" */n");
b.append("public class ").append(e.getName());
if(e.getSuperType() != null) {
b.append(" extends ").append(compile(e.getSuperType()));
}
b.append(" {n");
for(Feature f: e.getFeatures()) {
if(f instanceof Property)
feature((Property)f);
Instanceof
else if(f instanceof Operation)
feature((Operation)f);
Cascades
}
b.append("}n");
return b.toString();
}
public String feature(Property property) {
StringBuilder b = new StringBuilder();
String type = compile(property.getType());
String name = property.getName();
b.append("// property ").append(name).append("n");
b.append("private ").append(type).append(" ").append(name).append("n");
b.append("n");
b.append("public ").append(type).append("get").append(name).append("() {n");
b.append(" return ").append(name).append(";n");

81. }
b.append("}n");
return b.toString();
}
public String feature(Property property) {
StringBuilder b = new StringBuilder();
String type = compile(property.getType());
String name = property.getName();
b.append("// property ").append(name).append("n");
b.append("private ").append(type).append(" ").append(name).append("n");
b.append("n");
b.append("public ").append(type).append("get").append(name).append("() {n");
b.append(" return ").append(name).append(";n");
b.append("}n");
b.append("n");
b.append("public ").append("set").append(name)
.append("(").append(type).append(" ").append(name).append("){n");
b.append(" this.").append(name).append(" = ").append(name).append(";n");
b.append("}n");
b.append("n");
return b.toString();
}
Noisy String
public String feature(Operation operation) {
StringBuilder b = new StringBuilder(); Concatenation
String name = operation.getName();
b.append("// operation ").append(name).append("n");
b.append(compile(operation.getType())).append(" ").append(name).append("(");
boolean isFirst = true;
for(JvmFormalParameter p: operation.getParams()) {

85. Statically
Typed

86. Statically Xbase
Typed Expressions

87. « RICH STRINGS »

88. POLYMORPHIC
dispatch

89. COMPILES TO

90. DEPENDENCY
@InjectION

91. TOOLING

92. Indigo - June 22nd