The ability to extend programming languages with domain-specific concepts is becoming an essential technology for developing complex software. However, many domain-specific languages are implemented in a way that interact poorly with the host language. There are a number of tools that aim to improve the situation by simplifying the creation of domain-specific languages, and allow easier interactions between the host language and the domain-specific language. However, many of these tools are limited to a single host language, and rarely allow extending the language used for language creation. To improve the situation, we created the language platform Storm, which aims to make the creation and usage of multiple extensible languages easy and seamless. This is accomplished by means of a shared, standardized namespace and in-process code generation, which gives Storm a high degree of extensibility, making it possible to extend or replace the built-in languages at will.
{"title":"Storm: a language platform for interacting and extensible languages (tool demo)","authors":"Filip Strömbäck","doi":"10.1145/3276604.3276982","DOIUrl":"https://doi.org/10.1145/3276604.3276982","url":null,"abstract":"The ability to extend programming languages with domain-specific concepts is becoming an essential technology for developing complex software. However, many domain-specific languages are implemented in a way that interact poorly with the host language. There are a number of tools that aim to improve the situation by simplifying the creation of domain-specific languages, and allow easier interactions between the host language and the domain-specific language. However, many of these tools are limited to a single host language, and rarely allow extending the language used for language creation. To improve the situation, we created the language platform Storm, which aims to make the creation and usage of multiple extensible languages easy and seamless. This is accomplished by means of a shared, standardized namespace and in-process code generation, which gives Storm a high degree of extensibility, making it possible to extend or replace the built-in languages at will.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131930430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Live modeling enables modelers to incrementally update models as they are running and get immediate feedback about the impact of their changes. Changes introduced in a model may trigger inconsistencies between the model and its run-time state (e.g., deleting the current state in a statemachine); effectively requiring to migrate the run-time state to comply with the updated model. In this paper, we introduce an approach that enables to automatically migrate such run-time state based on declarative constraints defined by the language designer. We illustrate the approach using Nextep, a meta-modeling language for defining invariants and migration constraints on run-time state models. When a model changes, Nextep employs model finding techniques, backed by a solver, to automatically infer a new run-time model that satisfies the declared constraints. We apply Nextep to define migration strategies for two DSLs, and report on its expressiveness and performance.
{"title":"Constraint-based run-time state migration for live modeling","authors":"U. Tikhonova, J. Stoel, T. Storm, Thomas Degueule","doi":"10.1145/3276604.3276611","DOIUrl":"https://doi.org/10.1145/3276604.3276611","url":null,"abstract":"Live modeling enables modelers to incrementally update models as they are running and get immediate feedback about the impact of their changes. Changes introduced in a model may trigger inconsistencies between the model and its run-time state (e.g., deleting the current state in a statemachine); effectively requiring to migrate the run-time state to comply with the updated model. In this paper, we introduce an approach that enables to automatically migrate such run-time state based on declarative constraints defined by the language designer. We illustrate the approach using Nextep, a meta-modeling language for defining invariants and migration constraints on run-time state models. When a model changes, Nextep employs model finding techniques, backed by a solver, to automatically infer a new run-time model that satisfies the declared constraints. We apply Nextep to define migration strategies for two DSLs, and report on its expressiveness and performance.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"330 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124656825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interactive notebooks allow people to communicate and collaborate through a single rich document that might include live code, multimedia, computed results, and documentation, which is persisted as a whole for reproducibility. Notebooks are currently being used extensively in domains such as data science, data journalism, and machine learning. However, constructing a notebook interface for a new language requires a lot of effort. In this tool paper, we present Bacatá, a language parametric notebook generator for domain-specific languages (DSL) based on the Jupyter framework. Bacatá is designed so that language engineers may reuse existing language components (such as parsers, code generators, interpreters, etc.) as much as possible. Moreover, we explain the design of Bacatá and how DSL notebooks can be generated with minimum effort in the context of the Rascal meta programming system and language workbench.
{"title":"Bacatá: a language parametric notebook generator (tool demo)","authors":"M. V. Merino, J. Vinju, T. Storm","doi":"10.1145/3276604.3276981","DOIUrl":"https://doi.org/10.1145/3276604.3276981","url":null,"abstract":"Interactive notebooks allow people to communicate and collaborate through a single rich document that might include live code, multimedia, computed results, and documentation, which is persisted as a whole for reproducibility. Notebooks are currently being used extensively in domains such as data science, data journalism, and machine learning. However, constructing a notebook interface for a new language requires a lot of effort. In this tool paper, we present Bacatá, a language parametric notebook generator for domain-specific languages (DSL) based on the Jupyter framework. Bacatá is designed so that language engineers may reuse existing language components (such as parsers, code generators, interpreters, etc.) as much as possible. Moreover, we explain the design of Bacatá and how DSL notebooks can be generated with minimum effort in the context of the Rascal meta programming system and language workbench.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116515098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a tool architecture that supports migrating custom domain-specific language (DSL) implementations to a language workbench. We demonstrate an implementation of this architecture for models in the domains of defining component interfaces (IDL) and modeling system behavior (OIL) which are developed and used at a digital printer manufacturing company. Increasing complexity and the lack of DSL syntax and IDE support for existing implementations in Python based on XML syntax hindered their evolution and adoption. A reimplementation in Spoofax using modular language definition enables composition between IDL and OIL and introduces more concise DSL syntax and IDE support. The presented tool supports migrating to new implementations while being backward compatible with existing syntax and related tooling.
{"title":"Migrating custom DSL implementations to a language workbench (tool demo)","authors":"Jasper Denkers, L. V. Gool, E. Visser","doi":"10.1145/3276604.3276608","DOIUrl":"https://doi.org/10.1145/3276604.3276608","url":null,"abstract":"We present a tool architecture that supports migrating custom domain-specific language (DSL) implementations to a language workbench. We demonstrate an implementation of this architecture for models in the domains of defining component interfaces (IDL) and modeling system behavior (OIL) which are developed and used at a digital printer manufacturing company. Increasing complexity and the lack of DSL syntax and IDE support for existing implementations in Python based on XML syntax hindered their evolution and adoption. A reimplementation in Spoofax using modular language definition enables composition between IDL and OIL and introduces more concise DSL syntax and IDE support. The presented tool supports migrating to new implementations while being backward compatible with existing syntax and related tooling.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130816062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johannes Mey, René Schöne, G. Hedin, Emma Söderberg, Thomas Kühn, Niklas Fors, Jesper Öqvist, U. Assmann
Just like current software systems, models are characterised by increasing complexity and rate of change. Yet, these models only become useful if they can be continuously evaluated and validated. To achieve sufficiently low response times for large models, incremental analysis is required. Reference Attribute Grammars (RAGs) offer mechanisms to perform an incremental analysis efficiently using dynamic dependency tracking. However, not all features used in conceptual modelling are directly available in RAGs. In particular, support for non-containment model relations is only available through manual implementation. We present an approach to directly model uni- and bidirectional non-containment relations in RAGs and provide efficient means for navigating and editing them. This approach is evaluated using a scalable benchmark for incremental model editing and the JastAdd RAG system. Our work demonstrates the suitability of RAGs for validating complex and continuously changing models of current software systems.
{"title":"Continuous model validation using reference attribute grammars","authors":"Johannes Mey, René Schöne, G. Hedin, Emma Söderberg, Thomas Kühn, Niklas Fors, Jesper Öqvist, U. Assmann","doi":"10.1145/3276604.3276616","DOIUrl":"https://doi.org/10.1145/3276604.3276616","url":null,"abstract":"Just like current software systems, models are characterised by increasing complexity and rate of change. Yet, these models only become useful if they can be continuously evaluated and validated. To achieve sufficiently low response times for large models, incremental analysis is required. Reference Attribute Grammars (RAGs) offer mechanisms to perform an incremental analysis efficiently using dynamic dependency tracking. However, not all features used in conceptual modelling are directly available in RAGs. In particular, support for non-containment model relations is only available through manual implementation. We present an approach to directly model uni- and bidirectional non-containment relations in RAGs and provide efficient means for navigating and editing them. This approach is evaluated using a scalable benchmark for incremental model editing and the JastAdd RAG system. Our work demonstrates the suitability of RAGs for validating complex and continuously changing models of current software systems.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131434410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Model-driven engineering (MDE) promotes models as the principal assets in software projects. Models are built using a modelling language whose syntax is defined by a metamodel. Hence, objects in models are typed by a metamodel class, and this typing relation is static as it is established at creation time and cannot be changed later. This way, objects in MDE are closed and fixed with respect to the type they conform to, the slots/properties they have, and the constraints they should obey. This hampers the reuse of model-related artefacts like model transformations, as well as the opportunistic or dynamic combination of metamodels. To alleviate this rigidity, we propose making model objects open so that they can acquire or drop so-called facets, each one contributing a type, slots and constraints to the object. Facets are defined by regular metamodels, hence being a lightweight extension of standard metamodelling. Facet metamodels may declare usage interfaces, and it is possible to specify laws that govern how facets are to be assigned to the instances of a metamodel. In this paper, we describe our proposal, report on an implementation, and illustrate scenarios where facets have advantages over other techniques.
{"title":"Facet-oriented modelling: open objects for model-driven engineering","authors":"J. Lara, E. Guerra, J. Kienzle, Yanis Hattab","doi":"10.1145/3276604.3276610","DOIUrl":"https://doi.org/10.1145/3276604.3276610","url":null,"abstract":"Model-driven engineering (MDE) promotes models as the principal assets in software projects. Models are built using a modelling language whose syntax is defined by a metamodel. Hence, objects in models are typed by a metamodel class, and this typing relation is static as it is established at creation time and cannot be changed later. This way, objects in MDE are closed and fixed with respect to the type they conform to, the slots/properties they have, and the constraints they should obey. This hampers the reuse of model-related artefacts like model transformations, as well as the opportunistic or dynamic combination of metamodels. To alleviate this rigidity, we propose making model objects open so that they can acquire or drop so-called facets, each one contributing a type, slots and constraints to the object. Facets are defined by regular metamodels, hence being a lightweight extension of standard metamodelling. Facet metamodels may declare usage interfaces, and it is possible to specify laws that govern how facets are to be assigned to the instances of a metamodel. In this paper, we describe our proposal, report on an implementation, and illustrate scenarios where facets have advantages over other techniques.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131617588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Model-driven engineering advocates the use of models to describe and automate many software development tasks. The syntax of modelling languages is defined by meta-models, making them essential artefacts. A combination of product line engineering methods and meta-models has been proposed to enable specification of modelling language variants, e.g., to describe a range of systems. However, there is a lack of techniques for ensuring syntactic correctness of all meta-models within a family (including their OCL constraints), and semantic correctness related to properties of individual instances of the different variants. The absence of verification methods at the product-line level can cause synthesis of ill-formed meta-models and problematic feature combinations whose effect at the instance level may go unnoticed. To attack this problem, we propose an approach to lifting both the meta-model syntax checking and the satisfiability checking of properties of individual meta-model instances, to the product-line level. We validate the approach via a prototype tool called Merlin, and report on several experiments that show the advantages of our method w.r.t. an enumerative analysis approach.
{"title":"Analysing meta-model product lines","authors":"E. Guerra, J. Lara, M. Chechik, Rick Salay","doi":"10.1145/3276604.3276609","DOIUrl":"https://doi.org/10.1145/3276604.3276609","url":null,"abstract":"Model-driven engineering advocates the use of models to describe and automate many software development tasks. The syntax of modelling languages is defined by meta-models, making them essential artefacts. A combination of product line engineering methods and meta-models has been proposed to enable specification of modelling language variants, e.g., to describe a range of systems. However, there is a lack of techniques for ensuring syntactic correctness of all meta-models within a family (including their OCL constraints), and semantic correctness related to properties of individual instances of the different variants. The absence of verification methods at the product-line level can cause synthesis of ill-formed meta-models and problematic feature combinations whose effect at the instance level may go unnoticed. To attack this problem, we propose an approach to lifting both the meta-model syntax checking and the satisfiability checking of properties of individual meta-model instances, to the product-line level. We validate the approach via a prototype tool called Merlin, and report on several experiments that show the advantages of our method w.r.t. an enumerative analysis approach.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129802997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In scientific applications, physical quantities and units of measurement are used regularly. If the inherent incompatibility between these units is not handled properly it can lead to major, sometimes catastrophic, problems. Although the risk of a miscalculation is high and the cost equally so, almost none of the major programming languages has support for physical quantities. Instead, scientific code developers often make their own tools or rely on external libraries to help them spot or prevent these mistakes. We employed a systematic approach to examine and analyse all available physical quantity open-source libraries. Approximately 3700 search results across seven repository hosting sites were condensed into a list of 82 of the most comprehensive and well-developed libraries currently available. In this group, 30 different programming languages are represented. Out of these 82 libraries, 38 have been updated within the last two years. These 38 are summarised in this paper as they are deemed the most relevant. The conclusion we draw from these results is that there is clearly too much diversity, duplicated efforts, and a lack of code sharing and harmonisation which discourages use and adoption.
{"title":"The next 700 unit of measurement checkers","authors":"Oscar Bennich-Björkman, S. McKeever","doi":"10.1145/3276604.3276613","DOIUrl":"https://doi.org/10.1145/3276604.3276613","url":null,"abstract":"In scientific applications, physical quantities and units of measurement are used regularly. If the inherent incompatibility between these units is not handled properly it can lead to major, sometimes catastrophic, problems. Although the risk of a miscalculation is high and the cost equally so, almost none of the major programming languages has support for physical quantities. Instead, scientific code developers often make their own tools or rely on external libraries to help them spot or prevent these mistakes. We employed a systematic approach to examine and analyse all available physical quantity open-source libraries. Approximately 3700 search results across seven repository hosting sites were condensed into a list of 82 of the most comprehensive and well-developed libraries currently available. In this group, 30 different programming languages are represented. Out of these 82 libraries, 38 have been updated within the last two years. These 38 are summarised in this paper as they are deemed the most relevant. The conclusion we draw from these results is that there is clearly too much diversity, duplicated efforts, and a lack of code sharing and harmonisation which discourages use and adoption.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122230155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Advanced and mature language workbenches have been proposed in the past decades to develop Domain-Specific Languages (DSL) and rich associated environments. They all come in various flavors, mostly depending on the underlying technological space (e.g., grammarware or modelware). However, when the time comes to start a new DSL project, it often comes with the choice of a unique technological space which later bounds the possible expected features. In this tool paper, we introduce NabLab, a full-fledged industrial environment for scientific computing and High Performance Computing (HPC), involving several metamodels and grammars. Beyond the description of an industrial experience of the development and use of tool-supported DSLs, we report in this paper our lessons learned, and demonstrate the benefits from usefully combining metamodels and grammars in an integrated environment.
{"title":"Fostering metamodels and grammars within a dedicated environment for HPC: the NabLab environment (tool demo)","authors":"B. Lelandais, M. Oudot, B. Combemale","doi":"10.1145/3276604.3276620","DOIUrl":"https://doi.org/10.1145/3276604.3276620","url":null,"abstract":"Advanced and mature language workbenches have been proposed in the past decades to develop Domain-Specific Languages (DSL) and rich associated environments. They all come in various flavors, mostly depending on the underlying technological space (e.g., grammarware or modelware). However, when the time comes to start a new DSL project, it often comes with the choice of a unique technological space which later bounds the possible expected features. In this tool paper, we introduce NabLab, a full-fledged industrial environment for scientific computing and High Performance Computing (HPC), involving several metamodels and grammars. Beyond the description of an industrial experience of the development and use of tool-supported DSLs, we report in this paper our lessons learned, and demonstrate the benefits from usefully combining metamodels and grammars in an integrated environment.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127771842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
At SLE in 2014, Ridge presented the P3 combinator library with which parsers can be developed for left-recursive, non-deterministic and ambiguous grammars. A combinator expression in P3 yields a binarised grammar reflecting the expression's structure. The grammar is given to an underlying, generalised parsing procedure computing all derivations. In this paper we present a combinator library with a similar architecture to P3, adjusting it to avoid grammar binarisation. Avoiding binarisation has a significant positive effect on the running times of the underlying parsing procedure, which we demonstrate using real-world grammars. Binarisation is avoided by restricting the applicability of combinators, resulting in combinator expressions closely resembling BNF fragments. Usability is recovered by defining coercions that automatically convert expressions where necessary. As the underlying parsing procedure, we use a purely functional variant of generalised top-down (GLL) parsing.
{"title":"GLL parsing with flexible combinators","authors":"L. T. V. Binsbergen, E. Scott, A. Johnstone","doi":"10.1145/3276604.3276618","DOIUrl":"https://doi.org/10.1145/3276604.3276618","url":null,"abstract":"At SLE in 2014, Ridge presented the P3 combinator library with which parsers can be developed for left-recursive, non-deterministic and ambiguous grammars. A combinator expression in P3 yields a binarised grammar reflecting the expression's structure. The grammar is given to an underlying, generalised parsing procedure computing all derivations. In this paper we present a combinator library with a similar architecture to P3, adjusting it to avoid grammar binarisation. Avoiding binarisation has a significant positive effect on the running times of the underlying parsing procedure, which we demonstrate using real-world grammars. Binarisation is avoided by restricting the applicability of combinators, resulting in combinator expressions closely resembling BNF fragments. Usability is recovered by defining coercions that automatically convert expressions where necessary. As the underlying parsing procedure, we use a purely functional variant of generalised top-down (GLL) parsing.","PeriodicalId":117525,"journal":{"name":"Proceedings of the 11th ACM SIGPLAN International Conference on Software Language Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129490572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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