Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | ACM Digital Library |
|---|---|
| Author | Pitts, Andrew M. |
| Abstract | Tell category theorists about the concept of abstract syntax for a language and they may say "that's just the initial algebra for a sum-of-products functor on the category of sets". Despite what you might think, they are trying to be helpful since the initiality property is the common denominator of both definitions by structural recursion and proofs by structural induction [5, Sect. 4.4]. In recent years we have learned how to extend this initial algebra view of abstract syntax to encompass languages with statically scoped binders. In the presence of such binders one wants to abstract away from the specific names of bound variables, either by quotienting parse trees by a suitable notion of alpha-equivalence, or by replacing conventional trees with ones containing de Bruijn indices [1]. By changing from the category of sets to other well-known, but still 'set-like' categories of sheaves or presheaves, one can regain an initial algebra view of this even more than normally abstract syntax---the pay-off being new and automatically generated forms of structural recursion and induction that respect alpha-equivalence [2, 3]. One good test of these new ideas is to see if they give rise to new forms of functional programming. In fact they do. The paper [6] sketches a functional programming language for representing and manipulating syntactical structure involving binders, based on the mathematical model of variable-binding in [3, 4]. In this ML-like language there are new forms of type for names and name-binding that come along with facilities for declaring fresh names, for binding names in abstractions and for pulling apart such name-abstractions via pattern-matching. The key idea is that properly abstract uses of names, i.e. ones that do not descend below the level of alpha-conversion, can be imposed on the user by a static type system that deduces information about the freshness of names. Even though we appear to be giving users a 'gensym' facility, the type system restricts the way it can be used to the extent that we keep within effect-free functional programming, in the sense that the usual laws of pure functional programming remain valid (augmented with new laws for names and name-abstractions). In this talk I will introduce this new approach to representing languages static binders in functional programming and discuss some of the difficulties we have had verifying its semantic properties. |
| Starting Page | 1 |
| Ending Page | 1 |
| Page Count | 1 |
| File Format | |
| DOI | 10.1145/507546.507637 |
| Journal | ACM SIGPLAN Notices (SIGP) |
| Volume Number | 36 |
| Issue Number | 10 |
| Language | English |
| Publisher | Association for Computing Machinery (ACM) |
| Publisher Date | 1983-05-01 |
| Publisher Place | New York |
| Access Restriction | Subscribed |
| Content Type | Text |
| Resource Type | Article |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|