A newtype declaration in Haskell introduces a new type renaming an existing type. The two types are viewed by the programmer as semantically different, but share the same runtime representation. When operations on the two semantic views coincide, the run-time cost of conversion between the two types is reduced to zero (in both directions) because of this common representation. We describe a new language feature called Shared Subtypes (SSubtypes), which generalizes these properties of the newtype declaration. SSubtypes allow programmers to specify subtype rules between types and sharing rules between data constructors. A value of a type T, where T is a subtype of U, can always be cast, at no cost, to value of type U. This free up-casting allows library functions that consume the supertype to be applied without cost to subtypes. Yet any semantic interpretations desired by the programmer can be enforced by the compiler. SSubtype declarations work particularly well with GADTs. GADTs use differing type indexes to make explicit semantic differences, by using a different index for each way of viewing the data. Shared subtypes allow GADTs to share the same runtime representation as a reference type, of which the GADT is a refinement.
{"title":"Shared subtypes: subtyping recursive parametrized algebraic data types","authors":"Ki Yung Ahn, T. Sheard","doi":"10.1145/1411286.1411297","DOIUrl":"https://doi.org/10.1145/1411286.1411297","url":null,"abstract":"A newtype declaration in Haskell introduces a new type renaming an existing type. The two types are viewed by the programmer as semantically different, but share the same runtime representation. When operations on the two semantic views coincide, the run-time cost of conversion between the two types is reduced to zero (in both directions) because of this common representation.\u0000 We describe a new language feature called Shared Subtypes (SSubtypes), which generalizes these properties of the newtype declaration. SSubtypes allow programmers to specify subtype rules between types and sharing rules between data constructors. A value of a type T, where T is a subtype of U, can always be cast, at no cost, to value of type U. This free up-casting allows library functions that consume the supertype to be applied without cost to subtypes. Yet any semantic interpretations desired by the programmer can be enforced by the compiler. SSubtype declarations work particularly well with GADTs. GADTs use differing type indexes to make explicit semantic differences, by using a different index for each way of viewing the data. Shared subtypes allow GADTs to share the same runtime representation as a reference type, of which the GADT is a refinement.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116225233","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 describe an implementation of session types in Haskell. Session types statically enforce that client-server communication proceeds according to protocols. They have been added to several concurrent calculi, but few implementations of session types are available. Our embedding takes advantage of Haskell where appropriate, but we rely on no exotic features. Thus our approach translates with minimal modification to other polymorphic, typed languages such as ML and Java. Our implementation works with existing Haskell concurrency mechanisms, handles multiple communication channels and recursive session types, and infers protocols automatically. While our implementation uses unsafe operations in Haskell, it does not violate Haskell's safety guarantees. We formalize this claim in a concurrent calculus with unsafe communication primitives over which we layer our implementation of session types, and we prove that the session types layer is safe. In particular, it enforces that channel-based communication follows consistent protocols.
{"title":"Haskell session types with (almost) no class","authors":"Riccardo Pucella, Jesse A. Tov","doi":"10.1145/1411286.1411290","DOIUrl":"https://doi.org/10.1145/1411286.1411290","url":null,"abstract":"We describe an implementation of session types in Haskell. Session types statically enforce that client-server communication proceeds according to protocols. They have been added to several concurrent calculi, but few implementations of session types are available.\u0000 Our embedding takes advantage of Haskell where appropriate, but we rely on no exotic features. Thus our approach translates with minimal modification to other polymorphic, typed languages such as ML and Java. Our implementation works with existing Haskell concurrency mechanisms, handles multiple communication channels and recursive session types, and infers protocols automatically.\u0000 While our implementation uses unsafe operations in Haskell, it does not violate Haskell's safety guarantees. We formalize this claim in a concurrent calculus with unsafe communication primitives over which we layer our implementation of session types, and we prove that the session types layer is safe. In particular, it enforces that channel-based communication follows consistent protocols.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115066243","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}
A. R. Yakushev, J. Jeuring, Patrik Jansson, Alex Gerdes, O. Kiselyov, B. C. D. S. Oliveira
Datatype-generic programming is defining functions that depend on the structure, or "shape", of datatypes. It has been around for more than 10 years, and a lot of progress has been made, in particular in the lazy functional programming language Haskell. There are morethan 10 proposals for generic programming libraries orlanguage extensions for Haskell. To compare and characterise the many generic programming libraries in atyped functional language, we introduce a set of criteria and develop a generic programming benchmark: a set of characteristic examples testing various facets of datatype-generic programming. We have implemented the benchmark for nine existing Haskell generic programming libraries and present the evaluation of the libraries. The comparison is useful for reaching a common standard for generic programming, but also for a programmer who has to choose a particular approach for datatype-generic programming.
{"title":"Comparing libraries for generic programming in haskell","authors":"A. R. Yakushev, J. Jeuring, Patrik Jansson, Alex Gerdes, O. Kiselyov, B. C. D. S. Oliveira","doi":"10.1145/1411286.1411301","DOIUrl":"https://doi.org/10.1145/1411286.1411301","url":null,"abstract":"Datatype-generic programming is defining functions that depend on the structure, or \"shape\", of datatypes. It has been around for more than 10 years, and a lot of progress has been made, in particular in the lazy functional programming language Haskell. There are morethan 10 proposals for generic programming libraries orlanguage extensions for Haskell. To compare and characterise the many generic programming libraries in atyped functional language, we introduce a set of criteria and develop a generic programming benchmark: a set of characteristic examples testing various facets of datatype-generic programming. We have implemented the benchmark for nine existing Haskell generic programming libraries and present the evaluation of the libraries. The comparison is useful for reaching a common standard for generic programming, but also for a programmer who has to choose a particular approach for datatype-generic programming.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121486784","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}
Yi is a text editor written in Haskell and extensible in Haskell. We take advantage of Haskell's expressive power to define embedded DSLs that form the foundation of the editor. In turn, these DSLs provide a flexible mechanism to create extended versions of the editor. Yi also provides some support for editing Haskell code.
{"title":"Yi: an editor in haskell for haskell","authors":"Jean-Philippe Bernardy","doi":"10.1145/1411286.1411294","DOIUrl":"https://doi.org/10.1145/1411286.1411294","url":null,"abstract":"Yi is a text editor written in Haskell and extensible in Haskell. We take advantage of Haskell's expressive power to define embedded DSLs that form the foundation of the editor. In turn, these DSLs provide a flexible mechanism to create extended versions of the editor. Yi also provides some support for editing Haskell code.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116198519","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}
Protecting confidentiality of data has become increasingly important for computing systems. Information-flow techniques have been developed over the years to achieve that purpose, leading to special-purpose languages that guarantee information-flow security in programs. However, rather than producing a new language from scratch, information-flow security can also be provided as a library. This has been done previously in Haskell using the arrow framework. In this paper, we show that arrows are not necessary to design such libraries and that a less general notion, namely monads, is sufficient to achieve the same goals. We present a monadic library to provide information-flow security for Haskell programs. The library introduces mechanisms to protect confidentiality of data for pure computations, that we then easily, and modularly, extend to include dealing with side-effects. We also present combinators to dynamically enforce different declassification policies when release of information is required in a controlled manner. It is possible to enforce policies related to what, by whom, and when information is released or a combination of them. The well-known concept of monads together with the light-weight characteristic of our approach makes the library suitable to build applications where confidentiality of data is an issue.
{"title":"A library for light-weight information-flow security in haskell","authors":"Alejandro Russo, Koen Claessen, John Hughes","doi":"10.1145/1411286.1411289","DOIUrl":"https://doi.org/10.1145/1411286.1411289","url":null,"abstract":"Protecting confidentiality of data has become increasingly important for computing systems. Information-flow techniques have been developed over the years to achieve that purpose, leading to special-purpose languages that guarantee information-flow security in programs. However, rather than producing a new language from scratch, information-flow security can also be provided as a library. This has been done previously in Haskell using the arrow framework. In this paper, we show that arrows are not necessary to design such libraries and that a less general notion, namely monads, is sufficient to achieve the same goals. We present a monadic library to provide information-flow security for Haskell programs. The library introduces mechanisms to protect confidentiality of data for pure computations, that we then easily, and modularly, extend to include dealing with side-effects. We also present combinators to dynamically enforce different declassification policies when release of information is required in a controlled manner. It is possible to enforce policies related to what, by whom, and when information is released or a combination of them. The well-known concept of monads together with the light-weight characteristic of our approach makes the library suitable to build applications where confidentiality of data is an issue.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"210 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120899764","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}
It can be very difficult to debug impure code, let alone prove its correctness. To address these problems, we provide a functional specification of three central components of Peyton Jones's awkward squad: teletype IO, mutable state, and concurrency. By constructing an internal model of such concepts within our programming language, we can test, debug, and reason about programs that perform IO as if they were pure. In particular, we demonstrate how our specifications may be used in tandem with QuickCheck to automatically test complex pointer algorithms and concurrent programs.
{"title":"Beauty in the beast","authors":"Wouter Swierstra, Thorsten Altenkirch","doi":"10.1145/1291201.1291206","DOIUrl":"https://doi.org/10.1145/1291201.1291206","url":null,"abstract":"It can be very difficult to debug impure code, let alone prove its correctness. To address these problems, we provide a functional specification of three central components of Peyton Jones's awkward squad: teletype IO, mutable state, and concurrency. By constructing an internal model of such concepts within our programming language, we can test, debug, and reason about programs that perform IO as if they were pure. In particular, we demonstrate how our specifications may be used in tandem with QuickCheck to automatically test complex pointer algorithms and concurrent programs.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133807941","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 propose an extension to list comprehensions that makes it easy to express the kind of queries one would write in SQL using ORDER BY, GROUP BY, and LIMIT. Our extension adds expressive power to comprehensions, and generalises the SQL constructs that inspired it. It is easy to implement, using simple desugaring rules.
{"title":"Comprehensive comprehensions","authors":"S. Jones, P. Wadler","doi":"10.1145/1291201.1291209","DOIUrl":"https://doi.org/10.1145/1291201.1291209","url":null,"abstract":"We propose an extension to list comprehensions that makes it easy to express the kind of queries one would write in SQL using ORDER BY, GROUP BY, and LIMIT. Our extension adds expressive power to comprehensions, and generalises the SQL constructs that inspired it. It is easy to implement, using simple desugaring rules.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129224927","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 describe the design, implementation and use of HPC, a tool-kit to record and display Haskell Program Coverage. HPC includes tools that instrument Haskell programs to record program coverage, run instrumented programs, and display information derived from coverage data in various ways.
{"title":"Haskell program coverage","authors":"Andy Gill, C. Runciman","doi":"10.1145/1291201.1291203","DOIUrl":"https://doi.org/10.1145/1291201.1291203","url":null,"abstract":"We describe the design, implementation and use of HPC, a tool-kit to record and display Haskell Program Coverage. HPC includes tools that instrument Haskell programs to record program coverage, run instrumented programs, and display information derived from coverage data in various ways.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125696051","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}
Quasiquoting allows programmers to use domain specific syntax to construct program fragments. By providing concrete syntax for complex data types, programs become easier to read, easier to write, and easier to reason about and maintain. Haskell is an excellent host language for embedded domain specific languages, and quasiquoting ideally complements the language features that make Haskell perform so well in this area. Unfortunately, until now no Haskell compiler has provided support for quasiquoting. We present an implementation in GHC and demonstrate that by leveraging existing compiler capabilities, building a full quasiquoter requires little more work than writing a parser. Furthermore, we provide a compile-time guarantee that all quasiquoted data is type-correct.
{"title":"Why it's nice to be quoted: quasiquoting for haskell","authors":"G. Mainland","doi":"10.1145/1291201.1291211","DOIUrl":"https://doi.org/10.1145/1291201.1291211","url":null,"abstract":"Quasiquoting allows programmers to use domain specific syntax to construct program fragments. By providing concrete syntax for complex data types, programs become easier to read, easier to write, and easier to reason about and maintain. Haskell is an excellent host language for embedded domain specific languages, and quasiquoting ideally complements the language features that make Haskell perform so well in this area. Unfortunately, until now no Haskell compiler has provided support for quasiquoting. We present an implementation in GHC and demonstrate that by leveraging existing compiler capabilities, building a full quasiquoter requires little more work than writing a parser. Furthermore, we provide a compile-time guarantee that all quasiquoted data is type-correct.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127717615","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}
Circular programs are a powerful technique to express multiple traversal algorithms as a single traversal function in a lazy setting. In this paper, we present a shortcut deforestation technique to calculate circular programs. The technique we propose takes as input the composition of two functions, such that the first builds an intermediate structure and some additional context information which are then processed by the second one, to produce the final result. Our transformation into circular programs achieves intermediate structure deforestation and multiple traversal elimination. Furthermore, the calculated programs preserve the termination properties of the original ones.
{"title":"A shortcut fusion rule for circular program calculation","authors":"J. Fernandes, Alberto Pardo, J. Saraiva","doi":"10.1145/1291201.1291216","DOIUrl":"https://doi.org/10.1145/1291201.1291216","url":null,"abstract":"Circular programs are a powerful technique to express multiple traversal algorithms as a single traversal function in a lazy setting. In this paper, we present a shortcut deforestation technique to calculate circular programs. The technique we propose takes as input the composition of two functions, such that the first builds an intermediate structure and some additional context information which are then processed by the second one, to produce the final result. Our transformation into circular programs achieves intermediate structure deforestation and multiple traversal elimination. Furthermore, the calculated programs preserve the termination properties of the original ones.","PeriodicalId":188691,"journal":{"name":"ACM SIGPLAN Symposium/Workshop on Haskell","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128323276","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：