Difference between pages "D45 General Platform Maintenance" and "The Use of Theories in Code Generation"

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= Overview =
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= Defining Translations Using The Theory Plug-in =
The Rodin platform versions concerned by this deliverable are:
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The theory plug-in is used to add mathematical extensions to Rodin. The theories are created, and deployed, and can then be used in any models in the workspace. When dealing with implementation level models, such as in Tasking Event-B, we need to consider how to translate newly added types and operators into code. We have augmented the theory interface with a Translation Rules section. This enables a user to define translation rules that map Event-B formulas to code.
* 2.1(08.02.2011),
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== Translation Rules==
* 2.2(01.06.2011),
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<div id="fig:Translation Rules">
* 2.2.2(01.08.2011),
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<br/>
* 2.3(04.10.2011),
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[[Image:TheoryCGRules.png|center||caption text]]
* 2.4(31.01.2011),
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<center>'''Figure 1''': Translation Rules</center>
* 2.5(30.04.2011).
+
<br/>
This year, the maintenance carried on fixing identified bugs, although an emphasis was put on correcting usability issues. Indeed, during the annual meeting in Nice, the WP9 members agreed to refocus on the needed tasks to address some specific bugs and issues reported by DEPLOY partners, and wished resolved by the end of DEPLOY. Thus, no new features were implemented but those appearing in the description of work. The tasks to be performed by the WP9 members were then scheduled, prioritized and regularly updated during the WP9 bi-weekly meetings. The updates allowed to capture and integrate rapidly some minor changes to enhance the usability of the platform which were required by the DEPLOY partners. The following paragraphs will give an overview of the the work that has been performed concerning maintenance on the existing platform components (i.e. core platform and plug-ins).
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</div>
  
See the Release Notes<ref name="documentation">http://wiki.event-b.org/index.php/D32_General_Platform_Maintenance#Available_Documentation</ref> and the SourceForge<ref name=documentation>http://wiki.event-b.org/index.php/D45_General_Platform_Maintenance#Available_Documentation</ref> databases (bugs and feature requests) for details about the previous and upcoming releases of the Rodin platform.
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Figure 1 shows the interface, and some translations rules of the mapping to Ada.
  
* General platform maintenance
+
The theory is given a name, and may import some other theories. Type parameters can be added, and we use them here to type the meta-variables. The meta-variable ''a'' is restricted to be an integer type, but meta-variable ''c'' can be any type. Meta-variables are used in the translator rules for pattern matching.
The maintenance done to overcome Rodin scalability weaknesses and enhance the proving experience will be detailed in a separate chapter. However, some features initially planned and some other which were later added and prioritized are worth to mention:
 
:*Possibility to highlight patterns in the ProverUI,
 
:*A better output providing warnings and errors in case of wrong or missing building configurations,
 
:*The switch to Eclipse 3.7,
 
:*A Handbook to complete and enhance the existing documentation.
 
  
* {{TODO}} An overview of the contribution about Mathematical extensions / Theory Plug-in (Issam Maamria)
+
Translator rules are templates, which are used in pattern matching. Event-B formulas are defined on the left hand side of the rule, and the code to be output (as text) appears on the right hand side of the matching rule. During translation an abstract syntax tree (AST) representation of the formula is used. The theory plug-in attempts to match the formulas in the rules with each syntactic element of the AST. As it does so it builds the textual output as a string, until the whole AST has been successfully matched. When a complete tree is matched, the target code is returned. If the AST is not matched, a warning is issued, and a string representation of the original formula is returned.
  
* {{TODO}} An overview of the contribution about Plug-in Incompatibilities (All partners)
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== Type Rules for Code Generation ==
  
* {{TODO}} An overview of the contribution about Modularisation (Alexei Illiasov)
+
The type rules section, shown in Figure 1, is where the relationship is defined, between Event-B types and the type system of the implementation.
  
* {{TODO}} An overview of the contribution about Decomposition (Renato Silva)
+
= Adding New (implementation-level) Types =
 +
When we are working at abstraction levels close to the implementation level, we may make an implementation decision which requires the introduction of a new type to the development. We give an example of our approach, where we add a new array type, shown in Figure 2, and then define its translation to code.
  
* {{TODO}} An overview of the contribution about Team-based Development (Colin Snook, Vitaly Savicks)
+
== An Array Type Definition ==
 +
<div id="fig:Extension with an Array Type">
 +
<br/>
 +
[[Image:ArrayDef.png|center||caption text]]
 +
<center>'''Figure 2''': Array Definition</center>
 +
<br/>
 +
</div>
  
* {{TODO}} An overview of the contribution about UML-B (Colin Snook, Vitaly Savicks)
+
The array operator notation is defined in the expression array(s: P(T)); and the semantics is defined in the direct definition. arrayN constrains the arrays to be of fixed length. Array lookup, update, and constructor operators are subsequently defined. In the next step we need to define any translations required to implement the array in code.
  
== An overview of the contribution about ProR (Michael Jastram) ==
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== Translation Rules ==
  
ProR is a replacement of the original requirements plug-in, which got discontinued in 2010.  It is based on the OMG ReqIF standard (<ref name="reqif">http://www.omg.org/spec/ReqIF/</ref>), which provides interoperability with industry tools. It evolved into the Eclipse Foundation project "Requirements Modeling Framework" (RMF, <ref name="rmf">http://eclipse.org/rmf</ref>), resulting in significant visibility.  ProR is independent from Rodin.  Integration is achieved with a separate plug-in that provides support for traceability and model integration.
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<div id="Translation Rules for the Array Type">
 +
<br/>
 +
[[Image:ArrayTrans.png|center||caption text]]
 +
<center>'''Figure 3''': Translation Rules for the Array Type</center>
 +
<br/>
 +
</div>
  
= Motivations =
+
Figure 3 shows the Ada translation; beginning with the meta-variable definitions that are used for pattern matching in the translation rules. Each of the operators; ''newArray'', and ''update'', and an expression using the ''lookup'' operator, are mapped to their implementations on the right hand side of the rule. The ''Type Rules'' section describes the implementation's description of the ''arrayN'' type.
The tasks to solve the issues faced by the DEPLOY partners have been listed and have been assigned to groups according to their priority. A high priority means a high need in the outcome of a given task. The group 1 has the highest priority, the group 2 has an intermediate priority, and the group 3 has the lowest priority. The group 4 concerns topics that could not be resourced during the lifetime of DEPLOY.The prover integrity item, although not being directly covered, has been partially addressed thanks to Isabelle and SMT integration. Unfortunately, the originally planned export of full proofs and integrity check was too ambitious to be fully achieved in the scope of DEPLOY.
 
 
 
{{SimpleHeader}}
 
|-
 
! scope=col | Group 1 (highest priority) || Responsible
 
|-
 
|Performance <br /> - Core (large models, etc.) <br /> - GUI (incl. prover UI, edition, etc.) || SYSTEREL
 
|-
 
|Prover Performances <br /> - New rewriting rules / inference rules <br /> - Automatic tactics (preferences, timeout, etc.) || SYSTEREL
 
|-
 
|ProB Disprover (incl. counter examples to DLF POs) || Düsseldorf
 
|-
 
|Stability (crash, corruption, etc.)  || SYSTEREL
 
|-
 
|Editors || SYSTEREL/Düsseldorf
 
|-
 
|}
 
{{SimpleHeader}}
 
|-
 
! scope=col | Group 2 || Responsible
 
|-
 
| Prover Performances <br /> - SMT provers integration <br /> - connection with Isabelle  <br /> - Mathematical extensions <br /> - ProB || <br />SYSTEREL <br /> ETH Zürich <br /> Southampton/SYSTEREL <br /> Düsseldorf
 
|-
 
|Scalability <br /> - Decomposition <br /> - Modularisation plug-in <br /> - Team-based development || <br /> Southampton <br /> Newcastle <br /> Southampton
 
|-
 
|Plug-in incompatibilities || Newcastle
 
|-
 
|Model-based testing || Pitesti/Düsseldorf
 
|-
 
|ProR || Düsseldorf
 
|}
 
{{SimpleHeader}}
 
|-
 
! scope=col | Group 3 || Responsible
 
|-
 
|Scalability <br /> - Generic instantiation <br /> - UML-B maintenance <br /> || <br /> Southampton <br /> ETH Zürich/Southampton
 
|-
 
|Code Generation || Southampton
 
|}
 
{{SimpleHeader}}
 
|-
 
! scope=col | Group 4
 
|-
 
|Prover Integrity
 
|-
 
|Integrity of Code Generation
 
|}
 
== Platform maintenance ==
 
The platform maintenance, as it can be deduced from the above tables in section [[#Motivations | Motivations]], mainly concerned stability and performance improvement. These topics will be discussed and detailed in a separate chapter about scalability improvements.<br>
 
However, other improvements of utmost importance were made on the platform. These improvements either came from DEPLOY partners specific needs, or were corresponding to previously identified needs (listed in D32 - Model Construction tools & Analysis III Deliverable).
 
Hence we review below the motivations of some noteworthy implemented features:
 
* A Possibility to highlight patterns in the Prover UI.
 
This feature came from a request of DEPLOY partners<ref name="searchInPUI">https://sourceforge.net/tracker/?func=detail&atid=651672&aid=3092835&group_id=108850</ref>, often facing the need to find particular patterns such as expressions in long predicates (e.g. long goals). Since Rodin 2.2, and its new Proving UI interface, a nice feature was added, allowing to search and highlight a string pattern into the whole Proving UI views and editors. This function as also been enabled on direct selection of text in this UI.
 
* A better output providing warnings and errors in case of wrong or missing building configurations.
 
This issue, often seen as a bug or as a plug-in incompatibility, was raised when a user imports and tries to use a model on a platform with some missing required plug-ins. The user often thought his models corrupted whereas Rodin was not able to build them, and hid this information to the user. This is why, since Rodin 2.3, an output has been provided in such case, taking the form of warnings or errors that any user can understand and review. This is a first answer to Rodin plug-in incompatibilities issues.
 
* The switch to Eclipse 3.7.
 
Due to the major improvements made every year in Eclipse releases and the continuously growing number of contributing projects which are for some of them used as basis for Rodin plug-ins, the Rodin platform follows the evolution and is adapted every year quickly to the latest Eclipse version available. This year, Rodin 2.3 originated the switch from Eclipse 3.6 to Eclipse 3.7.
 
* A Handbook to complete and enhance the existing documentation.
 
At the DEPLOY Plenary Meeting in Zürich in 2010, it has been stated that the current documentation, in its state at that time, would not support a engineer starting using the tools without significant help of an expert <ref name="documentationoverhaul>http://wiki.event-b.org/index.php/User_Documentation_Overhaul</ref>. Significant efforts to improve the documentation were performed and coordinated by Düsseldorf, and took form of a handbook<ref name="RodinHandbook">http://handbook.event-b.org/</ref>. The Rodin handbook has the aim to minimize the access to an expert, by providing the necessary assistance to an engineer in the need to be productive using Event-B and the Rodin toolset. The contents of the handbook, user oriented, were originated by some contents of the Event-B wiki.
 
 
 
== Mathematical extensions / Theory Plug-in ==
 
{{TODO}} ''To be completed by Issam Maamria''
 
== Plug-in Incompatibilities ==
 
By its extensibility nature, the Rodin platform is susceptible to incompatibilities. Indeed, there are many ways in which incompatibilities could occur, and it occurred in the lifetime of DEPLOY. A good example, is the dependency management. Suppose that a bundle x_v1.0 is needed by a plug-in A (i.e. a dependency from A has been defined to x in at most the version 1.0) and installed in Rodin. Then the plug-in x_v1.1 is needed by a plug-in B. The both versions 1.0 and 1.1 of x could not be installed and used at the same time and create thus some usage incompatibility.
 
 
 
== Modularisation ==
 
{{TODO}} ''To be completed by Alexei Illiasov''
 
== Decomposition ==
 
{{TODO}} ''To be completed by Renato Silva'' 
 
== Team-based Development ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== UML-B ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== ProR ==
 
 
 
While the original requirements plug-in for Rodin was useful as a prototype, a number of shortcomings lead to a new development.  In particular, the original plug-in was a traceability tool with externally managed requirements.  With ProR, requirements are authored and edited within Eclipse.  The original plug-in supported only a limited number of attributes and flat (unstructured) requirements.  ProR supports all data structures that the ReqIF standard<ref name="reqif">http://www.omg.org/spec/ReqIF/</ref> supports. Further, ReqIF-support for industry tools like Rational DOORS, MKS or IRqA is expected in the near future, while the original plug-in required a custom adaptor for each data format.
 
 
 
ProR is developed independently from Rodin.  Dependencies to Rodin exist only in the Rodin integration plug-in.  This significantly decreases the maintenance effort for the integration plugin, while increasing the visibility of ProR in the Open Source community.  The move of ProR from the University of Düsseldorf to the Eclipse Foundation increases visibility even further.  The Rodin integration plug-in is maintained as an independent project at github.
 
 
 
= Choices / Decisions =
 
== Platform maintenance ==
 
* Revisited task priority
 
This year, the process of giving priority to maintenance tasks was revisited according the the refocus mentioned above. The aim was to address all the major scalability issues before the end of DEPLOY. Thus, the requests coming from DEPLOY partners were given high priorities, and they were also prioritized against the already planned tasks coming from both DEPLOY partners and the Description of Work.
 
* Keep 32-bit versions of the Rodin platform on linux and windows systems
 
It was asked by end users to make both 32-bit and 64-bit versions of the Rodin platform available for Linux and Windows platforms. Only a 64-bit version of Rodin is available on Mac platforms as 32-bit Mac (early 2006) platforms are no longer maintained. The request to offer 64-bit was motivated by the possibility to increase for them the available Java heap size for some memory greedy platforms (these before 2.3). However, the drawbacks of assembling and maintaining more platforms (5 platforms instead of 3) and the corrections brought to the database which improved the memory consumption pushed away the limitations of the platform, made this request not relevant for now.
 
 
 
== Mathematical extensions / Theory Plug-in ==
 
{{TODO}} ''To be completed by Issam Maamria''
 
== Plug-in Incompatibilities ==
 
It has been decided in cooperation with all the WP9 partners to find better ways to address the plug-in incompatibility issues. First of all, the various partners refined the concept of "plug-in incompatibility". Hence, various aspects could be identified and some specific answers were given to each of them. The user could then defined more clearly the incompatibility faced. Plug-in incompatibilities can be separated in two categories:
 
:* Rodin platform/plug-in incompatibilities, due to some wrong match between Rodin included packages and the plug-in dependencies (i.e. needed packages). These incompatibilities, when reported, allowed the plug-in developers to contact SYSTEREL in charge of managing the packages shipped with a given version of Rodin. It could also allow traceability of incompatibilities and information to the user through a specific and actualized table on each Rodin release notes page on the Wiki<ref name="incompTableA">http://wiki.event-b.org/index.php/Rodin_Platform_Releases#Current_plug-ins</ref>.
 
:* Plug-in/plug-in incompatibilities, due to some wrong match between needed/installed packages, or API/resources incompatible usage. A table was created on each release notes wiki page, and a procedure was defined<ref name="incompTableB">http://wiki.event-b.org/index.php/Rodin_Platform_Releases#Known_plug-in_incompatibilities</ref> so that identified incompatibilities are listed and corrected by the concerned developers.
 
It appeared that cases of using a model which references some missing plug-ins were formerly often seen as compatibility issues although they were not.<br>
 
After the incompatibilities have been identified, the developing counterparts being concerned assigned special tasks and coordination to solve issues the soonest as possible. Incompatibilities are often due to little glitches or desynchronisation and such direct coordination of counterpart appeared appropriate because quick and effective.
 
 
 
== Modularisation ==
 
{{TODO}} ''To be completed by Alexei Illiasov''
 
== Decomposition ==
 
{{TODO}} ''To be completed by Renato Silva'' 
 
== Team-based Development ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== UML-B ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== ProR ==
 
 
 
The following key decisions were made when developing ProR:
 
 
 
* '''New development, rather than continuing the original plug-in''' - the architecture of ProR differs significantly from that of the original plug-in (see [[D45_General_Platform_Maintenance#ProR]].  In addition, new technologies like EMF promised a cleaner, more powerful framework for an implementation.
 
 
 
* '''ReqIF as the underlying data model''' - the ReqIF standard <ref name="reqif">http://www.omg.org/spec/ReqIF/</ref> is gaining traction and promises interoperability with industry tools.  In addition, a digital version of the data model was available for free and could serve as the foundation for the model code.
 
 
 
* '''The Eclipse Modeling Framework''' (EMF) was identified as a technology that would allow a quick and clean foundation for an implementation. Further, the Rodin EMF-plug-in represents a convenient interface for integrating ProR and ProB.  Last, the digital data model from the OMG could be imported directly into EMF and used for generating the model code.
 
 
 
* '''Keeping ProR independent from Rodin''' - There is significant interest in ReqIF right now, but this interest is unrelated to formal methods.  By providing an implementation that is independent from Rodin, we have a much larger target group of potential users and developers.  By carefully designing extension points, we can still provide a powerful Rodin integration.
 
 
 
* '''Eclipse Foundation Project''' - we were actively establishing an open source community around ProR.  By recruiting engaged partners early on, development progressed faster than anticipated.  By becoming an Eclipse Foundation project <ref name="rmf">http://eclipse.org/rmf</ref>, we exceeded our goals in this respect.
 
 
 
= Available Documentation =
 
* Core platform:
 
:The following pages give useful information about the Rodin platform releases:
 
:* Release notes<ref>http://wiki.event-b.org/index.php/Rodin_Platform_Releases</ref>.
 
:* Bugs<ref>https://sourceforge.net/tracker/?group_id=108850&atid=651669</ref>.
 
:* Feature requests<ref>https://sourceforge.net/tracker/?group_id=108850&atid=651672</ref>.
 
*The Rodin handbook is proposed as a PDF version and a HTML version and a dedicated plug-in makes it available as help within Rodin<ref name="RodinHandbook">http://handbook.event-b.org/</ref>.
 
 
 
*{{TODO}}  Links for Mathematical extensions / Theory Plug-in
 
*{{TODO}}  Links for Modularisation
 
*{{TODO}}  Links for Decomposition
 
*{{TODO}}  Links for Team-based Development
 
*{{TODO}}  Links for UML-B
 
* Links for ProR
 
** ProR at the Eclipse Foundation <ref name="rmf">http://eclipse.org/rmf</ref>
 
** ProR Documentation for end users and plugin developers <ref>http://pror.org</ref>
 
 
 
= Status =
 
== Platform maintenance ==
 
By the end of the project, there are :
 
* xx bugs reported and open. All with a priority lower or equal to 5.
 
* xx feature requests expressed and still open.
 
 
 
== Mathematical extensions / Theory Plug-in ==
 
{{TODO}} ''To be completed by Issam Maamria''
 
== Plug-in Incompatibilities ==
 
As the time of writing this deliverable, no plug-in incompatibilities are left or known to exist between the platform and plug-ins or between plug-ins.
 
 
 
== Modularisation ==
 
{{TODO}} ''To be completed by Alexei Illiasov''
 
== Decomposition ==
 
{{TODO}} ''To be completed by Renato Silva'' 
 
== Team-based Development ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== UML-B ==
 
{{TODO}} ''To be completed by Colin Snook, Vitaly Savicks''
 
== ProR ==
 
{{TODO}} ''To be completed by Michael Jastram''
 
 
 
 
 
= References =
 
<references/>
 
 
 
[[Category:D45 Deliverable]]
 

Revision as of 15:51, 15 May 2012

Defining Translations Using The Theory Plug-in

The theory plug-in is used to add mathematical extensions to Rodin. The theories are created, and deployed, and can then be used in any models in the workspace. When dealing with implementation level models, such as in Tasking Event-B, we need to consider how to translate newly added types and operators into code. We have augmented the theory interface with a Translation Rules section. This enables a user to define translation rules that map Event-B formulas to code.

Translation Rules


caption text
Figure 1: Translation Rules


Figure 1 shows the interface, and some translations rules of the mapping to Ada.

The theory is given a name, and may import some other theories. Type parameters can be added, and we use them here to type the meta-variables. The meta-variable a is restricted to be an integer type, but meta-variable c can be any type. Meta-variables are used in the translator rules for pattern matching.

Translator rules are templates, which are used in pattern matching. Event-B formulas are defined on the left hand side of the rule, and the code to be output (as text) appears on the right hand side of the matching rule. During translation an abstract syntax tree (AST) representation of the formula is used. The theory plug-in attempts to match the formulas in the rules with each syntactic element of the AST. As it does so it builds the textual output as a string, until the whole AST has been successfully matched. When a complete tree is matched, the target code is returned. If the AST is not matched, a warning is issued, and a string representation of the original formula is returned.

Type Rules for Code Generation

The type rules section, shown in Figure 1, is where the relationship is defined, between Event-B types and the type system of the implementation.

Adding New (implementation-level) Types

When we are working at abstraction levels close to the implementation level, we may make an implementation decision which requires the introduction of a new type to the development. We give an example of our approach, where we add a new array type, shown in Figure 2, and then define its translation to code.

An Array Type Definition


caption text
Figure 2: Array Definition


The array operator notation is defined in the expression array(s: P(T)); and the semantics is defined in the direct definition. arrayN constrains the arrays to be of fixed length. Array lookup, update, and constructor operators are subsequently defined. In the next step we need to define any translations required to implement the array in code.

Translation Rules


caption text
Figure 3: Translation Rules for the Array Type


Figure 3 shows the Ada translation; beginning with the meta-variable definitions that are used for pattern matching in the translation rules. Each of the operators; newArray, and update, and an expression using the lookup operator, are mapped to their implementations on the right hand side of the rule. The Type Rules section describes the implementation's description of the arrayN type.