Polymorphism in the Spotlight: Studying Its Prevalence in Java and Smalltalk

Milojković, Nevena; Caracciolo, Andrea; Lungu, Mircea; Nierstrasz, Oscar; Roethlisberger, David; Robbes, Romain

doi:10.1109/icpc.2015.29

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…The actual type of the variable at run time is ColorForm, which is a subclass of Form. However, this is a common situation in object-oriented languages, due to a heavy use of polymorphism [41].…”

Section: Motivationmentioning

confidence: 99%

Exploiting Type Hints in Method Argument Names to Improve Lightweight Type Inference

Milojković

Ghafari

Nierstrasz

2017

2017 IEEE/ACM 25th International Conference on Program Comprehension (ICPC)

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The lack of static type information is one of the main obstacles to program comprehension in dynamically-typed languages. While static type inference algorithms try to remedy this problem, they usually suffer from the problem of false positives or false negatives. In order to partially compensate for the lack of static type information, a common practice in dynamically-typed languages is to name or annotate method arguments in such a way that they reveal their expected type, e.g., aString, anInt, or string: String. Recent studies confirmed that these type annotations are indeed frequently used by developers in dynamically-typed languages. We propose a lightweight heuristic that uses these hints from method argument names to augment the performance of a static type inference algorithm. The evaluation through a proof-ofconcept prototype implemented in Pharo Smalltalk shows that the augmented algorithm outperforms the basic algorithm, and correctly infers types for 81% more method arguments.

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Section: Motivationmentioning

confidence: 99%

Exploiting Type Hints in Method Argument Names to Improve Lightweight Type Inference

Milojković

Ghafari

Nierstrasz

2017

2017 IEEE/ACM 25th International Conference on Program Comprehension (ICPC)

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“…The only available information is that this variable needs to understand messages with 100 selectors methodClass and selector. Polymorphic selectors are frequently used in Smalltalk [21] which means that a large number of methods implement these selectors. In the Pharo image 4 we used for our experiments, there are 20 methods with selector methodClass and 67 methods with selector selector.…”

Section: Motivationmentioning

confidence: 99%

Mining inline cache data to order inferred types in dynamic languages

Milojković

Béra

Ghafari

et al. 2018

Science of Computer Programming

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The lack of static type information in dynamically-typed languages often poses obstacles for developers. Type inference algorithms can help, but inferring precise type information requires complex algorithms that are often slow.A simple approach that considers only the locally used interface of variables can identify potential classes for variables, but popular interfaces can generate a large number of false positives. We propose an approach called inline-cache type inference (ICTI) to augment the precision of fast and simple type inference algorithms. ICTI uses type information available in the inline caches during multiple software runs, to provide a ranked list of possible classes that most likely represent a variable's type. We evaluate ICTI through a proof-of-concept that we implement in Pharo Smalltalk. The analysis of the top-n+2 inferred types (where n is the number of recorded run-time types for a variable) for 5486 variables from four different software systems shows that ICTI produces promising results for about 75% of the variables. For more than 90% of variables, the correct runtime type is present among first six inferred types. Our ordering shows a twofold improvement when compared with the unordered basic approach, i.e., for a significant number of variables for which the basic approach offered ambiguous results, ICTI was able to promote the correct type to the top of the list.

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“…In the past he has been interested in assessing the prevalence of reuse by inheritance and invocation of software in different languages [1]. Currently he wants to expand his analysis to subtype polymorphism [2]. He believes that although polymorphism can be an elegant solution for modelling variability, it can make systems more difficult to understand.…”

Section: Introductionmentioning

confidence: 99%

“…This could represent an excellent candidate for applying the Goal-Question-Metric paradigm (GQM) [5]. GQM provides a three-step framework in which one must: (1) define a goal, (2) derive questions to determine if the goal is met, and (3) decide what metrics are suitable to answer the questions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Explora: A visualisation tool for metric analysis of software corpora

Merino

Lungu

Nierstrasz

2015

2015 IEEE 3rd Working Conference on Software Visualization (VISSOFT)

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Abstract-When analysing software metrics, users find that visualisation tools lack support for (1) the detection of patterns within metrics; and (2) enabling analysis of software corpora.In this paper we present Explora, a visualisation tool designed for the simultaneous analysis of multiple metrics of systems in software corpora. Explora incorporates a novel lightweight visualisation technique called PolyGrid that promotes the detection of graphical patterns. We present an example where we analyse the relation of subtype polymorphism with inheritance and invocation in corpora of Smalltalk and Java systems and find that (1) subtype polymorphism is more likely to be found in large hierarchies; (2) as class hierarchies grow horizontally, they also do so vertically; and (3) in polymorphic hierarchies the length of the name of the classes is orthogonal to the cardinality of the call sites.

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Polymorphism in the Spotlight: Studying Its Prevalence in Java and Smalltalk

Cited by 7 publications

References 24 publications

Exploiting Type Hints in Method Argument Names to Improve Lightweight Type Inference

Exploiting Type Hints in Method Argument Names to Improve Lightweight Type Inference

Mining inline cache data to order inferred types in dynamic languages

Explora: A visualisation tool for metric analysis of software corpora

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