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Documents authored by Alves, Sandra


Document
Linear Rank Intersection Types

Authors: Fábio Reis, Sandra Alves, and Mário Florido

Published in: LIPIcs, Volume 269, 28th International Conference on Types for Proofs and Programs (TYPES 2022)


Abstract
Non-idempotent intersection types provide quantitative information about typed programs, and have been used to obtain time and space complexity measures. Intersection type systems characterize termination, so restrictions need to be made in order to make typability decidable. One such restriction consists in using a notion of finite rank for the idempotent intersection types. In this work, we define a new notion of rank for the non-idempotent intersection types. We then define a novel type system and a type inference algorithm for the λ-calculus, using the new notion of rank 2. In the second part of this work, we extend the type system and the type inference algorithm to use the quantitative properties of the non-idempotent intersection types to infer quantitative information related to resource usage.

Cite as

Fábio Reis, Sandra Alves, and Mário Florido. Linear Rank Intersection Types. In 28th International Conference on Types for Proofs and Programs (TYPES 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 269, pp. 8:1-8:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{reis_et_al:LIPIcs.TYPES.2022.8,
  author =	{Reis, F\'{a}bio and Alves, Sandra and Florido, M\'{a}rio},
  title =	{{Linear Rank Intersection Types}},
  booktitle =	{28th International Conference on Types for Proofs and Programs (TYPES 2022)},
  pages =	{8:1--8:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-285-3},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{269},
  editor =	{Kesner, Delia and P\'{e}drot, Pierre-Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2022.8},
  URN =		{urn:nbn:de:0030-drops-184513},
  doi =		{10.4230/LIPIcs.TYPES.2022.8},
  annote =	{Keywords: Lambda-Calculus, Intersection Types, Quantitative Types, Tight Typings}
}
Document
A Quantitative Understanding of Pattern Matching

Authors: Sandra Alves, Delia Kesner, and Daniel Ventura

Published in: LIPIcs, Volume 175, 25th International Conference on Types for Proofs and Programs (TYPES 2019)


Abstract
This paper shows that the recent approach to quantitative typing systems for programming languages can be extended to pattern matching features. Indeed, we define two resource-aware type systems, named U and E, for a λ-calculus equipped with pairs for both patterns and terms. Our typing systems borrow some basic ideas from [Antonio Bucciarelli et al., 2015], which characterises (head) normalisation in a qualitative way, in the sense that typability and normalisation coincide. But, in contrast to [Antonio Bucciarelli et al., 2015], our systems also provide quantitative information about the dynamics of the calculus. Indeed, system U provides upper bounds for the length of (head) normalisation sequences plus the size of their corresponding normal forms, while system E, which can be seen as a refinement of system U, produces exact bounds for each of them. This is achieved by means of a non-idempotent intersection type system equipped with different technical tools. First of all, we use product types to type pairs instead of the disjoint unions in [Antonio Bucciarelli et al., 2015], which turn out to be an essential quantitative tool because they remove the confusion between "being a pair" and "being duplicable". Secondly, typing sequents in system E are decorated with tuples of integers, which provide quantitative information about normalisation sequences, notably time (cf. length) and space (cf. size). Moreover, the time resource information is remarkably refined, because it discriminates between different kinds of reduction steps performed during evaluation, so that beta, substitution and matching steps are counted separately. Another key tool of system E is that the type system distinguishes between consuming (contributing to time) and persistent (contributing to space) constructors.

Cite as

Sandra Alves, Delia Kesner, and Daniel Ventura. A Quantitative Understanding of Pattern Matching. In 25th International Conference on Types for Proofs and Programs (TYPES 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 175, pp. 3:1-3:36, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{alves_et_al:LIPIcs.TYPES.2019.3,
  author =	{Alves, Sandra and Kesner, Delia and Ventura, Daniel},
  title =	{{A Quantitative Understanding of Pattern Matching}},
  booktitle =	{25th International Conference on Types for Proofs and Programs (TYPES 2019)},
  pages =	{3:1--3:36},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-158-0},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{175},
  editor =	{Bezem, Marc and Mahboubi, Assia},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2019.3},
  URN =		{urn:nbn:de:0030-drops-130672},
  doi =		{10.4230/LIPIcs.TYPES.2019.3},
  annote =	{Keywords: Intersection Types, Pattern Matching, Exact Bounds}
}
Document
A Unifying Framework for Type Inhabitation

Authors: Sandra Alves and Sabine Broda

Published in: LIPIcs, Volume 108, 3rd International Conference on Formal Structures for Computation and Deduction (FSCD 2018)


Abstract
In this paper we define a framework to address different kinds of problems related to type inhabitation, such as type checking, the emptiness problem, generation of inhabitants and counting, in a uniform way. Our framework uses an alternative representation for types, called the pre-grammar of the type, on which different methods for these problems are based. Furthermore, we define a scheme for a decision algorithm that, for particular instantiations of the parameters, can be used to show different inhabitation related problems to be in PSPACE.

Cite as

Sandra Alves and Sabine Broda. A Unifying Framework for Type Inhabitation. In 3rd International Conference on Formal Structures for Computation and Deduction (FSCD 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 108, pp. 5:1-5:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{alves_et_al:LIPIcs.FSCD.2018.5,
  author =	{Alves, Sandra and Broda, Sabine},
  title =	{{A Unifying Framework for Type Inhabitation}},
  booktitle =	{3rd International Conference on Formal Structures for Computation and Deduction (FSCD 2018)},
  pages =	{5:1--5:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-077-4},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{108},
  editor =	{Kirchner, H\'{e}l\`{e}ne},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2018.5},
  URN =		{urn:nbn:de:0030-drops-91758},
  doi =		{10.4230/LIPIcs.FSCD.2018.5},
  annote =	{Keywords: simple types, type inhabitation, rewriting, PSPACE}
}
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