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start [2009/09/25 13:51]
aspectscript |
start [2009/10/26 14:43]
aspectscript |
| **AspectScript** is a [[http://en.wikipedia.org/wiki/JavaScript|JavaScript]] extension for Aspect-Oriented Programming (AOP) that currently works in [[http://www.mozilla.com|Mozilla Firefox]]. AspectScript is an aspect language that integrates (with) the main features of JavaScript such as first-class and higher-order functions, dynamic typing, and prototype-based programming. AspectScript is based on the pointcut-advice mechanism and includes the followings state-of-the-art AOP features: | **AspectScript** is a [[http://en.wikipedia.org/wiki/JavaScript|JavaScript]] extension for Aspect-Oriented Programming (AOP) that currently supports [[http://www.mozilla.com|Mozilla Firefox]] (no plug-ins or add-ons required!). AspectScript is an aspect language that integrates with the characterizing features of JavaScript such as first-class and higher-order functions, dynamic typing, and prototype-based programming. AspectScript is based on the pointcut-advice mechanism and includes the followings state-of-the-art AOP features: |
| | * **Higher-order aspects**: AspectScript is directly inspired by [[http://www.cs.usask.ca/~cjd032/downloads/AspectScheme/|AspectScheme]], in which aspects, pointcuts, and advices are first-class values. Consequently, they can be created and manipulated at runtime. An aspect in AspectScript is a pointcut-advice pair; pointcuts and advices are plain JavaScript functions. This feature allows programmers to use the full power of higher-order programming in AOP. |
| * ** An extensible join model**: The join point model is similar to the one found in [[http://www.eclipse.org/aspectj/|AspectJ]]. However, it is possible to extend it to identify other points of interest through customizable join points, similar to [[http://www.cs.iastate.edu/~ptolemy/|Ptolemy]]. | |
| * **Higher-order aspects**: Like [[http://www.cs.usask.ca/~cjd032/downloads/AspectScheme/|AspectScheme]], AspectScript aspects are first-class values (a pair pointcut-advice). Pointcuts and advices are plain JavaScript functions, which are first-class values as well. This feature allows programmers to use the full power of higher-order programming to define and manipulate aspects. | |
| * **Aspects in order**: By default in AspectScript, the base code is executed at a base level (level 0). This level is observed by aspects, which in turn execute at an aspect level (level 1). However, in AspectScript, aspects can also observe higher levels (level 1 for instance), which causes their execution to happen in level 2. AspectScript permits to modify the default behavior of execution levels using the semantics presented in [[http://www.pleiad.cl/research/scope#higher-order_aspects_in_order|Aspects in Order]], which gives complete control over which level a code is finally executed. | |
| * **Dynamic deployment of aspects with scoping strategies**: Aspects in AspectScript are dynamically deployed like in [[http://caesarj.org/|CaesarJ]] and [[http://www.cs.usask.ca/~cjd032/downloads/AspectScheme/|AspectScheme]]. In addition, the deployment of aspects can be expressively refined using [[http://www.pleiad.cl/research/scope#expressive_scoping_of_dynamically-deployed_aspects|Scoping Strategies]]. | |
| * **Control of aspect reentrancy**: As in most aspect languages, it is possible to have aspect reentrancy problems in AspectScript. For this reason, AspectScript allows programmers to control aspect reentrancy in a fine-grained manner following the semantics of [[http://www.pleiad.cl/research/scope#controlling_aspect_reentrancy|Controlling Aspect Reentrancy]]. | |
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| Despite the numerous AspectScript features, sensible default semantics make AspectScript very easy to use. For instance, to define an aspect that shows a message before calls to the **foo** function, it is only necessary to write: | * **Dynamic deployment of aspects with scoping strategies**: Aspects in AspectScript are dynamically deployed like in [[http://caesarj.org/|CaesarJ]] and [[http://www.cs.usask.ca/~cjd032/downloads/AspectScheme/|AspectScheme]]. In addition, the scope of dynamically deployed aspects can be expressively refined using [[http://www.pleiad.cl/research/scope#expressive_scoping_of_dynamically-deployed_aspects|Scoping Strategies]] ([[http://pleiad.dcc.uchile.cl/research/publications?key=tanter-aosd2008|AOSD'08]], [[http://pleiad.dcc.uchile.cl/research/publications?key=tanter-dls2009|DLS'09]]). |
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| | * ** Hybrid join point model**: At its core, AspectScript adopts a join point model in the line of that of [[http://www.eclipse.org/aspectj/| AspectJ]] (see [[jp_list|the join point model]]), but tailored for the JavaScript language. However, AspectScript not only supports implicitly-generated join points following the language model, but also provides the possibility to define custom join points triggered explicitly, as in [[http://www.cs.iastate.edu/~ptolemy/|Ptolemy]]. |
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| | Despite the numerous aspect-oriented features of AspectScript, it is still very easy to use, thanks to sensible default semantics. For instance, to define an aspect that shows a message before calls to the **foo** function, it is only necessary to write: |
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| <code java> | <code java> |
| AspectScript.before(pointcut, advice); | AspectScript.before(pointcut, advice); |
| </code> | </code> |
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| | * Do you want to see AspectScript in action? Please try the tetris game [[tetris|here]]. |
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| * Do you need more examples? You can find them [[examples|here]]. | * Do you need more examples? You can find them [[examples|here]]. |
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| * Does it seem complex? Do not give up!, you can follow our [[tutorial|tutorial]]. | * Do you want to learn more? You can follow our [[tutorial|tutorial]]. |
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| * Do you have any doubt? Please, do not hesitate to ask in our [[http://groups.google.com/group/aspectscript|mailing list]]. | * Do you have any doubt? Please, do not hesitate to ask in our [[http://groups.google.com/group/aspectscript|mailing list]]. |
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| We are convinced that AspectScript can be useful for both researchers and developers: | We are convinced that AspectScript can be useful for both researchers and developers: |
| | * **For developers**: AspectScript is a useful aspect language to modularize crosscutting concerns in the Web. Many common problems can be modularly solved using AspectScript! Take a look at the [[examples]] page. |
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| * **For researchers**: AspectScript provides an extensible testbed for the experimentation with new AOP features. | * **For researchers**: AspectScript provides an extensible testbed for the experimentation with new AOP features. |
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| * **For developers**: AspectScript is a useful aspect language to modularize crosscutting concerns in the Web. Many common problems can be modularly solved using AspectScript! Take a look at the [[examples]] page). | |
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| ====== Credits ====== | ====== Credits ====== |
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| AspectScript is designed and implemented at the [[http://www.pleiad.cl|Pleiad lab]] by [[http://www.pleiad.cl/people/pleger|Paul Leger]] and [[http://www.pleiad.cl/people/rtoledo|Rodolfo Toledo]], under the supervision of the professor [[http://www.pleiad.cl/people/etanter|Eric Tanter]]. | AspectScript is designed and implemented at the [[http://www.pleiad.cl|Pleiad lab]] by [[http://www.pleiad.cl/people/pleger|Paul Leger]] and [[http://www.pleiad.cl/people/rtoledo|Rodolfo Toledo]], under the supervision of the professor [[http://www.pleiad.cl/people/etanter|Éric Tanter]]. |
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