Beyond Annotations: A Proposal for Extensible Java XJ

1
Beyond AnnotationsA Proposal for Extensible
Java(XJ)

• Tony Clark, Thames Valley University
• Paul Sammut, HSBC
• James Willans, Ceteva
• tony.clark_at_tvu.ac.uk
• www.ceteva.com/home/tony.html

2
Domain Specific Languages

• Aims to provide a tailored language to support
  mixed languages language evolution.
• Pros declarative maintenance reuse
  verification
• Cons specialist skills no standard technology
  lack of integration.
• Technologies macros pre-processing
  roll-your-own chained calls.

3
DSLs Technology Problems

• Communication distributing new languages.
• Integration IDEs Analysis Tools.
• Modularity clear definition of syntax and
  semantics.
• DSL Types Internal and External.
• Syntax (concrete and abstract) standard
  extension mechanisms.

4
DSLs An OO Proposal

• Syntax Classes
• Modular class-based language constructs.
• Conservative extends base language.
• Fully Integrated static dynamic IDE.
• Standardized syntax extension AST manipulation
  static processing execution.

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Syntax Classes DSL Architecture
package p.q import language java.syntax.grammar
class mylang implements java.syntax.AST ...
_at_grammar // language definition
import language p.q.mylang class C void
m(...) ... _at_mylang //
Syntax and semantics defined // by class
mylang.

• modular.
• nesting.
• conservative.
• standard.

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Example DSL Constructs
public VectorltIntegergt add1(VectorltIntegergt nums)
return _at_Cmp(x 1) int x lt- nums

_at_Reader CallReader map(SVCL,ServiceCall)
4-18CustomerName 19-23CustomerID
24-27CallTypeCode 28-35DataOfCallString
end map(USGE,Usage) 4-8CustomerID
9-22CustomerName 30-30Cycle
31-36ReadDate end do ServiceCall Usage
_at_EntityBean Order persistAs "ORDER_TABLE"
private int id persistAs "ORDER_ID" (get,set)
private int address persistAs "SHIPPING_ADDRESS"
(get,set)
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Syntax Classes Technologies

• Grammars basic library synthesizes abstract
  syntax various languages possible.
• AST interface factories types eval compile
• Quasi-quotes working with concrete/abstract
  syntax ltogt.m(ltagt,1)
• Language import _at_ grammar .

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Review

• Implemented in XMF commercial tool open-source
  (www.ceteva.com)
• Superlanguages book (www.ceteva.com/docs/Superlan
  guages.pdf)
• DSLs require standard technology.
• Open up Java to define new languages.
• Issues language interaction IDE support
  analysis tool requirements.

9
Statement

• New languages and constructs can/should implement
  a standard interface to facilitate program
  analysis.