Here are the slides from my presentation at GR8Conf Europe 2011. I showed Groovy-Eclipse's new DSLD feature that improved DSL support in the editor.

1. What’s new in Groovy & Grails Support?
DSL Support in Groovy-Eclipse
Andrew Eisenberg, SpringSource Tools Team
© 2011 SpringSource, A division of VMware. All rights reserved

2. What’s new in Groovy & Grails Support?
Part 1
© 2011 SpringSource, A division of VMware. All rights reserved

3. New Groovy-Eclipse Support in 2.5.0
 DSL Descriptors (discussed later)
 Groovy 1.8
 Parameter guessing content assist
 Script outline view
 Distinguish read vs. write access in search
 Conditional breakpoints in Groovy files (STS only)
3

4. New Grails tooling support in STS 2.7.0.M1
 Service field content assist
 Groovy search results in GSPs
4

5. Gradle support in STS
Part 1.5
© 2011 SpringSource, A division of VMware. All rights reserved

6. First cut at Gradle support now available in STS
 Demoed this morning in the Gradle talk
 Yay!
6

7. DSL Support in Groovy-Eclipse
Part 2
© 2011 SpringSource, A division of VMware. All rights reserved

8. The Problem
8

9. A DSL for distance calculations
3.m + 2.yd + 2.mi - 1.km
In the Groovy editor:
Uh oh!
Can we do better???
9

10. The Solution:
DSL Descriptors (DSLDs)
10

11. DSL Descriptors
 Teach the IDE about DSLs through scripting
CONFIDENTIAL 11

12. DSL Descriptors
 In English:
• “Any subtype of Number should have the following properties: m, yd, mi, km”
 In DSLD:
• “Any subtype of Number”:
currentType( subType( Number ) )!
• “…the following properties…”:
[ “m”, “yd”, “cm”, “mi”, “km” ].each {!
property name:it, type:"Distance”!
}!
3.m + 2.yd + 2.mi - 1.km
12

13. Let’s see that
 Ex 1: Distances
13

14. Anatomy of a DSLD file
14

15. DSLD and the Inferencing Engine
 Hooks into Groovy-Eclipse’s type inferencing engine
• Visit each expression AST node
• Determine type using previous expression
• Move to next expression
 DSLD operates on Groovy AST Expression nodes
• Exposes Groovy AST nodes and uses Groovy API
 In the background, while typing (reconciling)
org.codehaus.groovy.ast.expr.Expression!
15

16. Pointcuts and Contribution blocks
 Pointcuts:
• Where to do it.
• What is the current expression?
• Declaring type? class Other {!
• Enclosing class? def x!
}!
 Contribution blocks: class Foo {!
• What to do def method() {!
• “Add” method new Other().x!
• “Add” property }!
}!
• (not at runtime, in the editor only)
16

17. What goes in a Contribution Block?
 property : “adds” a property (…).accept {!
• arguments property name: “myName”!
• name: “blarb” method name: “getMyName”!
}!
• type: “java.lang.String”
• declaringType :”com.foo.Frumble”
• isStatic: false
• doc: “Some html”
• provider: “My DSL”
 method : “adds” a method
• all arguments above, and
• params: [firstName:“java.lang.String”, lastName:“java.lang.String”]
• useNamedArgs: true
 name is required, others optional
17

18. Pointcuts
 currentType() : Matches on the current declaring type
 enclosingClass() : Matches on the enclosing class
 currentType(“com.bar.Foo”)
 methods(“run”)
 annotatedBy(“org.junit.runner.RunWith”)
 enclosingClass(
annotatedBy(“org.junit.runner.RunWith”) ) &
currentType(methods(“run”) )
18

19. Where does this pointcut match? What does it add?
(enclosingClass(annotatedBy(“org.junit.runner.RunWith”)) &
currentType(methods(“run”))).accept { property name:”blarb” }!
Looking for an expression that:
@RunWith(Sumthin) !
class Foo {!
def someTest() {! enclosed by
@RunWith
print “Hello”!
def x = new MyRunner()!
x.blarb! has run method
}!
blarb
}!
class MyRunner { def run() {…} }!
19

20. Wait…isn’t this Aspect-Oriented Programming?
 Pointcut
• Intentionally borrowed from AOP
 AspectJ: pointcuts and advice
• operates on Java instructions at runtime
class Foo {!
 DSLD: pointcuts and contribution blocks def x = {!
• operates on AST def i = 0!
org.codehaus.groovy.ast.expr.*!
 Join Point Model i++!
}!
• Join points (e.g., instructions, expressions)
}!
• Mechanism for quantifying join points (e.g., pointcuts)
• Means of affect at a join point (e.g., advice,
contribution blocks)
20

21. Other things to help with DSLDs
21

22. New DSLD Wizard
 File  New  Groovy DSL Descriptor
22

23. DSLD Preferences Page
23

24. Groovy Event Console
 Keep this open while implementing DSLDs:
• Shows exceptions
• Pointcuts
• Matches
 Find the Console here:
24

25. Groovy AST Viewer
 Exploration of AST of current Groovy file
25

26. Examples
26

27. Basic Script
Ex 2: Using the DSLD wizard
27

28. Meta DSL
Ex 3: DSLD script for editing DSLDs
28

29. AST Transforms
Ex 3: Standard AST Transforms
29

30. SwingBuilder
Ex 4: Long script, but simple to understand
30

31. Grails Constraints DSL
Ex 5: encapsulate Grails domain knowledge in a script
31

32. Criteria Queries
Ex 6: simple script, large effect
32

33. Griffon
Ex 7: from last night
33

34. What’s next?
34

35. DSLD is not complete
 Guided by user feedback
 Collaboration with library developers
• Grails, Gaelyk, Griffon, etc.
 Release standard DSLDs (AST Transforms, Builders, etc.)
• With Groovy-Eclipse?
• With Groovy core?
 More pointcuts
• What do users need that isn’t implemented?
• regex(), instanceof(), superType(), enclosingEnum(), etc.
 What about IntelliJ’s GDSL?
35

36. Thanks!
 More information:
• Google: groovy eclipse dsld
 Full documentation on Codehaus.org:
• http://docs.codehaus.org/display/GROOVY/DSL+Descriptors+for+Groovy-Eclipse
 Install from update site:
• http://dist.codehaus.org/groovy/distributions/greclipse/snapshot/e3.6/
 Mailing list:
• eclipse-plugin-users@codehaus.org
 Or chat with me whenever
36