there and back again · 2011. 1. 8. · there and back again bidirectional computation for software...

Bidirectional ComputationBidirectional Computation is WANTED in SE

BiX: A Bidirectional Tree Transformation LanguageBidirectional Graph Computation: Bidirectionalizing ATL

Conclusion

There and Back AgainBidirectional Computation for Software Engineering

Zhenjiang Hu

GRACE CenterNational Institute of Informaticc

November 12, 2008

Zhenjiang Hu There and Back Again



Conclusion

How do you synchronize your calenders?




Conclusion

DefinitionBasic PropertiesDirect Applications

Bidirectional Computation (Bidirectional Transformation)




Conclusion



src tgt




Conclusion



src tgt

tgt’

mod




Conclusion



src tgt

tgt’

mod

src’




Conclusion



src tgt

tgt’

mod

src’

get

put

It consists of a pair of computation forward and backward.




Conclusion


Stability

No change on the target implies no change on the source.

src tgt

tgt

no modification

src

get

put

put(get(s), s) = s




Conclusion


Reflectivity

Permitted changes on the target should be reflected to the source.

src tgt

tgt’

mod

src’

get

put

get(put(t ′, s)) = t ′




Conclusion


View Updating

Reflect changes on the view to the original relational database.

DB View

Ref: many studies in the database community[Bancilhon&Spyratos:81, Dayal&Bernstein, Gottlob et. al.:88 ]




Conclusion


Replicated Data Synchronization

Synchronization of data in different formats.

Ref: the Harmony project in Univ. of Pennsylvania[Pierce et. al: POPL’05, PODS’06, POPL’08].




Conclusion

Bidirectional Computation is WANTED in SE




Conclusion

Bidirectional Transformation in ABC

ABC: Architecture-Based Component composition (Peking Univ.)




Conclusion

Bidirectional Transformation in ABC

ABC: Architecture-Based Component composition (Peking Univ.)

Hu & Mei: Natural Science Funds for Distinguished Oversea Young Scholars

(2006-2008). Welcome to our workshop next January.




Conclusion

Challenges of BC for SE

Software Artifacts: Graphs

Software Development: Graph Transformations




Conclusion

Challenges of BC for SE

Software Artifacts: Graphs

Software Development: Graph Transformations

Perdita Stevens: Bidirectional Model Transformations in QVT:

Semantic Issues and Open Questions, Best Paper in MoDELS2007.

It is a big challenge to design a powerful language for

specifying graph computation with clear bidirectional

semantics that can support practical software

development.




Conclusion

BiXHow Powerful is BiX?

Languages for Bidirectional Computation

Languages with both forward and backward computationsemantics:

src tgt

tgtsrc

get

put




Conclusion


BiX: A Bidirectional XML Transformation Language




Conclusion



Inv: an injective language for revertible computation[MPC’04, APLAS’04]

X: a domain-specific bidirectional language for interactivedocument construction (with the dup primitive)[ACM PEPM’04, HOCS:08]

BiX: a bidirectional transformation language for general XMLprocessing (with function definitions and local bindings)[ACM PEPM’07]

... A general bidirectional functional language [ACM ICFP’07]




Conclusion



Inv: an injective language for revertible computation[MPC’04, APLAS’04]

X: a domain-specific bidirectional language for interactivedocument construction (with the dup primitive)[ACM PEPM’04, HOCS:08]

BiX: a bidirectional transformation language for general XMLprocessing (with function definitions and local bindings)[ACM PEPM’07]

... A general bidirectional functional language [ACM ICFP’07]

Write forward transformation and get backward transformation for free!




Conclusion


BiX

A Combinator-based language




Conclusion


BiX


Primitive bidirectional transformations for tree manipulation,which is extensible.




Conclusion


BiX


Primitive bidirectional transformations for tree manipulation,which is extensible.Combinators for composing smaller bidirectionaltransformations




Conclusion


BiX


Primitive bidirectional transformations for tree manipulation,which is extensible.Combinators for composing smaller bidirectionaltransformations

We only need to prepare a pair of transformations for eachprimitive bidirectional transformation, other backwardtransformations are obtained for free.




Conclusion


Primitive Bi-Transformations

Primitive bidirectional transformations for tree manipulation:

for tree destruction, e.g.,

xid

xleftchild

for tree construction, e.g.,

xconst t

xdup

xnewroot n




Conclusion


xid

Identity Transformation




Conclusion


xid


s s




Conclusion


xid


s s

t’

mod




Conclusion


xid


s s

t’

mod

t’

get

put




Conclusion


xid


s s

t’

mod

t’

get

put

get s = s

put t ′ s = t ′




Conclusion


xleftchild

Select the leftmost child of the root




Conclusion


xleftchild


s1 sn· · ·

s1




Conclusion


xleftchild


s1 sn· · ·

s1

s ′1

mod




Conclusion


xleftchild


s1 sn· · ·

s1

s ′1

mod

s ′1 sn· · ·

get

put




Conclusion


xleftchild


s1 sn· · ·

s1

s ′1

mod

s ′1 sn· · ·

get

put

get (Node n [s1, . . . , sn]) = s1put s ′1 (Node n [s1, . . . , sn]) = Node n [s ′1, . . . , sn]




Conclusion


Combinators

Used to construct bigger bidirectional transformations bycomposing smaller bidirectional transformations.

Sequential composition: x1 ; x2

Parallel composition: x1 || x2

Map to each: xmap x

Conditional: xif p x1 x2




Conclusion


Sequential Composition

src tgt

x1

tgt’

x2

src tgt’

x1 ; x2

get(x1 ; x2) s = getx2(getx1

s)

put(x1 ; x2) t ′ s = putx1(putx2

t ′ (getx1s)) s




Conclusion


Parallel Composition

s1 t1

x1

s2 t2

x2

s1 s2 t1 t2

x1 || x2




Conclusion


Map-to-each

si ti

x

s1 sn· · ·

t1 tn

· · ·xmap x




Conclusion


Conditional

If p s holds, then

s tx1

s txif p x1 x2

otherwise,

s tx2

s txif p x1 x2




Conclusion


How Powerful is BiX?

The core XSLT can be bidirectionalized with BiX [JSSST CS’07]

The core XQuery can be bidirectionalized with BiX [ACM PEPM’07]

http://www.ipl.t.u-tokyo.ac.jp/˜liu/BiXQuery.html




Conclusion


Application: Web Site Maintenance

Vu-X: update web pages on browsers in the WYSIWYG manner.

Ref: [PEPM’07, WSE’08]. (About 20,000 loc in BiX)




Conclusion


Application: Web Site Maintenance

Vu-X: update web pages on browsers in the WYSIWYG manner.

http://www.psdlab.org/vux/




Conclusion

ATLBidirectionalizing ATLA Small Demo

Can you bidirectionalize ATL, a popular modeltransformation language?




Conclusion


ATL

ATL (ATLAS Transformation Language) is a modeltransformation language for describing unidirectional modeltransformations.

Developed by the ATLAS Group (INRIA & LINA).

Has more than 100 transformation examples and manynontrivial use cases.




Conclusion


A Simple Model Transformation: UML2Java

A UML Model

<Class name=”Book” description=”a demo class”>

<attrs name=”title” type=”String”/>

<attrs name=”price” type=”Double”/>

</Class><Class name=” draft Authors”/>

⇓

A Java Model

<Class name=”Book”>

<fields name=” title” type=”String”/>

<fields name=” price” type=”Double”/>

</Class>




Conclusion


The Simple Model Transformation in ATL

module UML2Java;

create OUT : Java from IN : UML;

rule Class2Class {from u : UML!Class (

not u.name.startsWith(’ draft ’))to j : Java!Class (

name ← u.name,fields← u.attrs

)}

rule Attribute2Field {from a : UML!Attributeto f : Java!Field (

name ← ’ ’ + a.name,type ← a.type

)}




Conclusion


Bidirectionalzing ATL with BiX+ [ASE 2007]




Conclusion


A Model Transformation in ATL

...

rule Attribute2Field {from a : UML!Attributeto f : Java!Field (

name ← ’ ’ + a.name,type ← a.type

)}




Conclusion


ATL Byte Code

push "UML!Attribute"

push "IN"

call "S.allInstancesFrom(S):QJ"

iterate

store "a"

push "Java!Field"

new

store "f"

load "f"

push "_"

load "a"

get "name"

call "S.Concatenate(S):S"

set "name"

load "f"

load "a"

get "type"

set "type"

enditerate




Conclusion


Interpreting ATL Byte Codes by BiX+

instructions descriptionpush push a constant to the stackpop pop the top of the stackstore store a value into a local variableload load value from local variableif branch if the top of the stack is true

iterate delimitate the beginning of iteration on collection elementsenditerate delimitate the end of iteration on collection elementscall call a methodnew create a new model elementget fetch an attribute of a model elementset set an attribute of a model element

We omit the detailed discussion here.




Conclusion


A Small Demo

A UML Model





⇓

A Java Model




</Class>




Conclusion


A Small Demo

A UML Model




<attrs name=”authors” type=”String”/>


⇓

A Java Model




<comment text=” bookTitle cannot be null”/>

</Class>




Conclusion


A Small Demo

A UML Model






⇓

A Java Model





<comment text=” bookTitle cannot be null”/>

</Class>Zhenjiang Hu There and Back Again



Conclusion


Try it!

http://www.ipl.t.u-tokyo.ac.jp/˜xiong/modelSynchronization.html




Conclusion

Conclusion

Bidirectional transformation is fun!

Static ⇒ dynamic

Bidirectional transformation is useful!

Synchronization of data in different formatsDocument developmentSoftware Engineering

Bidirectional transformation is challenging!

Semantic issues, compositional construction, developmentenvironment, ...




Conclusion

Conclusion

Bidirectional transformation is fun!

Static ⇒ dynamic

Bidirectional transformation is useful!

Synchronization of data in different formatsDocument developmentSoftware Engineering

Bidirectional transformation is challenging!

Semantic issues, compositional construction, developmentenvironment, ...

⇓Linguistic Foundation for Bidirectional Graph Transformation

http://research.nii.ac.jp/˜hu/project/bix.html




Conclusion

Collaborators

University of TokyoE-Society Project (2004-)

Masato TakeichiKazutaka MatsudaYingfei XiongKeisuke Nakano (OB)Dongxi Liu (OB)Susumu Hayashi (OB)Shin-Cheng Mu (OB)

Peking UniversityNSF for DistinguishedOversea Young Scholars(2006-)

Hong MeiHaiyan ZhaoGang HuangHui SongYingfei Xiong

National Institute of InformaticsGrand-Challenge Project at NII (2008-)

Soichiro HidakaHiroyuki Kato




Conclusion

There and Back Again




Conclusion

There and Back Again

Thank You!




Conclusion

GRACE Int’l Meeting on Bidirectional Transformation

The first Dagstuhl-style seminars in Asia

Shonan Village Center (Japan), December 15th-18th, 2008

Organizers: Zhenjiang Hu, Nate Foster, Krzysztof Czarnecki


there and back again · 2011. 1. 8. · there and back again bidirectional computation for software...

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