ICFP Papers

PACMPL (ICFP) seeks contributions on the design, implementations, principles, and uses of functional programming, covering the entire spectrum of work, from practice to theory, including its peripheries. Authors of papers published in this issue of PACMPL will present their work at during the in-person conference, providing an opportunity for researchers and developers to hear about the latest work in functional programming.

Call for Papers

PACMPL issue ICFP 2025 seeks original papers on the art and science of functional programming. Submissions are invited on all topics from principles to practice, from foundations to features, and from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects, concurrency, or parallelism. Topics of interest include (but are not limited to):

• Language Design: concurrency, parallelism, and distribution; modularity; components and composition; meta-programming; macros; pattern matching; type systems; type inference; dependent types; effect types; gradual types; refinement types; session types; interoperability; domain-specific languages; imperative programming; object-oriented programming; logic programming; probabilistic programming; reactive programming; generic programming; bidirectional programming.

• Implementation: abstract machines; virtual machines; interpretation; compilation; compile-time and run-time optimisation; garbage collection and memory management; runtime systems; multi-threading; exploiting parallel hardware; interfaces to foreign functions, services, components, or low-level machine resources.

• Software-Development Techniques: algorithms and data structures; design patterns; specification; verification; validation; proof assistants; debugging; testing; tracing; profiling; build systems; program synthesis.

• Foundations: formal semantics; lambda calculus; program equivalence; rewriting; type theory; logic; category theory; computational effects; continuations; control; state; names and binding; program verification.

• Analysis and Transformation: control flow; data flow; abstract interpretation; partial evaluation; program calculation.

• Applications: symbolic computing; formal-methods tools; artificial intelligence; systems programming; distributed systems and web programming; hardware design; databases; scientific and numerical computing; graphical user interfaces; graphics and multimedia; GPU programming; scripting; system administration; security.

• Education: teaching introductory programming; mathematical proof; algebra.

Submissions will be evaluated according to their relevance, correctness, significance, originality, and clarity. Each submission should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. The technical content should be accessible to a broad audience.

PACMPL issue ICFP 2025 also welcomes submissions in two separate categories — Functional Pearls and Experience Reports — that must be marked as such when submitted and that need not report original research results. Detailed guidelines on both categories are given at the end of this call.

In an effort to achieve a balanced, diverse program, each author may be listed as a (co)author on a maximum of four submissions. Authors who require financial support to attend the conference can apply for PAC funding (http://www.sigplan.org/PAC/).

The General Chair and PC Chair may not submit papers. PC members (other than the PC Chair) may submit papers.

Please contact the Program Chair if you have questions or are concerned about the appropriateness of a topic.

Full Double-Blind Reviewing Process

ICFP 2025 will use a full double-blind reviewing process (similar to the one used for ICFP 2024 but different from the lightweight double-blind process used in previous years). This means that identities of authors will not be made visible to reviewers until after conditional-acceptance decisions have been made, and then only for the conditionally-accepted papers. The use of full double-blind reviewing has several consequences for authors.

Submissions: Authors must omit their names and institutions from their paper submissions. In addition, references to authors’ own prior work should be in the third person (e.g., not “We build on our previous work …” but rather “We build on the work of …”).

Supplementary material: Authors must fully anonymize any supplementary material (see below). Links to supplementary material on external websites are not permitted.

Author response: In responding to reviews, authors should not say anything that reveals their identity, since author identities will not be revealed to reviewers at that stage of the reviewing process.

Dissemination of work under submission: Authors are welcome to disseminate their ideas and post draft versions of their paper(s) on their personal website, institutional repository, or arXiv (reviewers will be asked to turn off arXiv notifications during the review period). But authors should not take steps that would almost certainly reveal their identities to members of the Program Committee, e.g., directly contacting PC members or publicizing the work on widely-visible social media or major mailing lists used by the community.

The purpose of the above restrictions is to help the Program Committee and external reviewers come to a judgment about the paper without bias, not to make it impossible for them to discover the authors’ identities if they were to try. In particular, nothing should be done in the name of anonymity that weakens the quality of the submission. However, there are occasionally cases where adhering to the above restrictions is truly difficult or impossible for one reason or another. In such cases, the authors should contact the Program Chair to discuss the situation and how to handle it. The FAQ on Double-Blind Reviewing (https://popl24.sigplan.org/track/POPL-2024-popl-research-papers#FAQ-on-Double-Blind-Reviewing) addresses many common scenarios and answers many common questions about this topic. But there remain many grey areas and trade-offs. If you have any doubts about how to interpret the double-blind rules or you encounter a complex case that is not clearly covered by the FAQ, please contact the Program Chair for guidance.

Preparation of submissions

Deadline: The deadline for submissions is Thursday, 27 February , 2025, Anywhere on Earth (https://www.timeanddate.com/time/zones/aoe). This deadline will be strictly enforced.

Formatting: Submissions must be in PDF format, printable in black and white on US Letter sized paper and interpretable by common PDF tools. All submissions must adhere to the “ACM Small” template that is available (in both LaTeX and Word formats) from https://www.acm.org/publications/authors/submissions.

Please download the latest version of the ACM style from https://www.acm.org/publications/authors/submissions, since the citation format has recently been changed.

See also PACMPL’s Information and Guidelines for Authors at https://pacmpl.acm.org/authors.cfm.

There is a limit of 25 pages for a full paper or Functional Pearl and 12 pages for an Experience Report; in either case, the bibliography and an optional clearly marked appendix will not be counted against these limits. Submissions that exceed the page limits or, for other reasons, do not meet the requirements for formatting, will be summarily rejected.

Submission: Submissions will be accepted at https://icfp25.hotcrp.com/

Improved versions of a paper may be submitted at any point before the submission deadline using the same web interface.

Author Response Period: Authors will have a 96-hour period, starting at 00:00 (midnight) AOE on Monday, 28 April, 2025, to read reviews and respond to them.

Appendix and Supplementary Material: Authors have the option to include a clearly marked appendix and/or to attach supplementary material to a submission, on the understanding that reviewers may choose not to look at such an appendix or supplementary material. Supplementary material may be uploaded as a separate PDF document or tarball. Any supplementary material must be uploaded at submission time, not by providing a URL in the paper that points to an external repository. All supplementary material must be anonymised.

Authorship Policies: All submissions are expected to comply with the ACM Policies for Authorship that are detailed at https://www.acm.org/publications/authors/information-for-authors.

Republication Policies: Each submission must adhere to SIGPLAN’s republication policy, as explained on the web at http://www.sigplan.org/Resources/Policies/Republication.

Review Process

This section outlines the two-stage process with double-blind reviewing that will be used to select papers for PACMPL issue ICFP 2025. Like last year, ICFP 2025 will adapt a full double-blind reviewing process. More information see below.

ICFP 2025 will have an Associate Chair who will help the PC Chair monitor reviews, solicit external expert reviews for submissions when there is not enough expertise on the committee, and facilitate reviewer discussions.

ICFP 2025 will employ a two-stage review process. The first stage in the review process will assess submitted papers using the criteria stated above and will allow for feedback and input on initial reviews through the author response period mentioned previously. As a result of the review process, a set of papers will be conditionally accepted and all other papers will be rejected. Authors will be notified of these decisions on 23 May, 2025.

Authors of conditionally accepted papers will be provided with committee reviews along with a set of mandatory revisions. By 12 June, 2025, the authors should provide a second revised submission. The second and final reviewing phase assesses whether the mandatory revisions have been adequately addressed by the authors and thereby determines the final accept/reject status of the paper. The intent and expectation is that the mandatory revisions can feasibly be addressed within three weeks.

The second submission should clearly identify how the mandatory revisions were addressed. To that end, the second submission must be accompanied by a cover letter mapping each mandatory revision request to specific parts of the paper. The cover letter will facilitate a quick second review, allowing for confirmation of final acceptance within two weeks. Conversely, the absence of a cover letter will be grounds for the paper’s rejection.

Information for Authors of Accepted Papers

• As a condition of acceptance, final versions of all papers must adhere to the ACM Small format. The page limit for the final versions of papers will be increased by two pages to help authors respond to reviewer comments and mandatory revisions: 27 pages plus bibliography for a regular paper or Functional Pearl, 14 pages plus bibliography for an Experience Report.

• Authors of accepted submissions will be required to agree to one of the three ACM licensing options, one of which is Creative Commons CC-BY publication; this is the option recommended by the PACMPL editorial board. A reasoned argument in favour of this option can be found in the article Why CC-BY? published by OASPA, the Open Access Scholarly Publishers Association. The other options are copyright transfer to ACM or retaining copyright but granting ACM exclusive publication rights.

• PACMPL is a Gold Open Access journal, and authors are encouraged to publish their work under a CC-BY license. Gold Open Access guarantees permanent free online access to the definitive version in the ACM Digital Library, and the recommended CC-BY option also allows anyone to copy and distribute the work with attribution. Gold Open Access has been made possible by generous funding through ACM SIGPLAN, which will cover all open access costs in the event authors cannot. Authors who can cover the costs may do so by paying an Article Processing Charge (APC). PACMPL, SIGPLAN, and ACM Headquarters are committed to exploring routes to making Gold Open Access publication both affordable and sustainable.

• ACM Author-Izer is a unique service that enables ACM authors to generate and post links on either their home page or institutional repository for visitors to download the definitive version of their articles from the ACM Digital Library at no charge. Downloads through Author-Izer links are captured in official ACM statistics, improving the accuracy of usage and impact measurements. Consistently linking to the definitive version of an ACM article should reduce user confusion over article versioning. After an article has been published and assigned to the appropriate ACM Author Profile pages, authors should visit http://www.acm.org/publications/acm-author-izer-service to learn how to create links for free downloads from the ACM DL.

• The official publication date is the date the papers are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work.

• Authors of each accepted submission are invited to attend and be available for the presentation of that paper at the conference. The schedule for presentations will be determined and shared with authors after the full program has been selected.

ORCID: ORCID provides a persistent digital identifier (an ORCID iD) that you own and control, and that distinguishes you from every other researcher: https://orcid.org/. ACM now require an ORCID iD for every author of a paper, not just the corresponding author. So, the author who is filling out the permission form should make sure they have the ORCID iDs for all of their coauthors before filling out the form. Any authors who do not yet have an ORCID iD can go to https://orcid.org/register to have one assigned.

Artifact Evaluation

Authors of papers that are conditionally accepted in the first phase of the review process will be encouraged (but not required) to submit supporting materials for Artifact Evaluation. These items will then be reviewed by an Artifact Evaluation Committee, separate from the paper Review Committee, whose task is to assess how the artifacts support the work described in the associated paper. Papers that go through the Artifact Evaluation process successfully will receive a seal of approval printed on the papers themselves. Authors of accepted papers will be encouraged to make the supporting materials publicly available upon publication of the papers, for example, by including them as “source materials” in the ACM Digital Library. An additional seal will mark papers whose artifacts are made available, as outlined in the ACM guidelines for artifact badging.

Participation in Artifact Evaluation is voluntary and will not influence the final decision regarding paper acceptance.

Special categories of papers

In addition to research papers, PACMPL issue ICFP solicits two kinds of papers that do not require original research contributions: Functional Pearls, which are full papers, and Experience Reports, which are limited to half the length of a full paper. Authors submitting such papers should consider the following guidelines.

Functional Pearls

A Functional Pearl is an elegant essay about something related to functional programming. Examples include, but are not limited to:

• a new and thought-provoking way of looking at an old idea
• an instructive example of program calculation or proof
• a nifty presentation of an old or new data structure
• an interesting application of functional programming techniques
• a novel use or exposition of functional programming in the classroom

While pearls often demonstrate an idea through the development of a short program, there is no requirement or expectation that they do so. Thus, they encompass the notions of theoretical and educational pearls.

Functional Pearls are valued as highly and judged as rigorously as ordinary papers, but using somewhat different criteria. In particular, a pearl is not required to report original research, but, it should be concise, instructive, and entertaining. A pearl is likely to be rejected if its readers get bored, if the material gets too complicated, if too much-specialised knowledge is needed, or if the writing is inelegant. The key to writing a good pearl is polishing.

A submission that is intended to be treated as a pearl must be marked as such on the submission web page and should contain the words “Functional Pearl” somewhere in its title or subtitle. These steps will alert reviewers to use the appropriate evaluation criteria. Pearls will be combined with ordinary papers, however, for the purpose of computing the conference’s acceptance rate.

Experience Reports

The purpose of an Experience Report is to describe the experience of using functional programming in practice, whether in industrial application, tool development, programming education, or any other area.

Possible topics for an Experience Report include, but are not limited to:

• insights gained from real-world projects using functional programming
• comparison of functional programming with conventional programming in the context of an industrial project or a university curriculum
• project-management, business, or legal issues encountered when using functional programming in a real-world project
• curricular issues encountered when using functional programming in education
• real-world constraints that created special challenges for an implementation of a functional language or for functional programming in general

An Experience Report is distinguished from a normal PACMPL issue ICFP paper by its title, by its length, and by the criteria used to evaluate it.

• Both in the papers and in any citations, the title of each accepted Experience Report must end with the words “(Experience Report)” in parentheses. The acceptance rate for Experience Reports will be computed and reported separately from the rate for ordinary papers.
• Experience Report submissions can be at most 12 pages long, excluding bibliography.
• Each accepted Experience Report will be presented at the conference, but depending on the number of Experience Reports and regular papers accepted, authors of Experience Reports may be asked to give shorter talks.
• Because the purpose of Experience Reports is to enable our community to understand the application of functional programming, an acceptable Experience Report need not add to the body of knowledge of the functional-programming community by presenting novel results or conclusions. It is sufficient if the report describes an illuminating experience with functional programming, or provides evidence for a clear thesis about the use of functional programming. The experience or thesis must be relevant to ICFP, but it need not be novel.

The review committee will accept or reject Experience Reports based on whether they judge the paper to illuminate some aspect of the use of functional programming. Anecdotal evidence will be acceptable provided it is well-argued and the author explains what efforts were made to gather as much evidence as possible. Typically, papers that show how functional programming was used are more convincing than papers that say only that functional programming was used. It can be especially effective to present comparisons of the situations before and after the experience described in the paper, but other kinds of evidence would also make sense, depending on context. Experience drawn from a single person’s experience may be sufficient, but more weight will be given to evidence drawn from the experience of groups of people.

An Experience Report should be short and to the point. For an industrial project, it should make a claim about how well functional programming worked and why; for a pedagogy paper, it might make a claim about the suitability of a particular teaching style or educational exercise. Either way, it should produce evidence to substantiate the claim. If functional programming worked in this case in the same ways it has worked for others, the paper need only summarise the results — the main part of the paper should discuss how well it worked and in what context. Most readers will not want to know all the details of the experience and its implementation, but the paper should characterise it and its context well enough so that readers can judge to what degree this experience is relevant to their own circumstances. The paper should take care to highlight any unusual aspects; specifics about the experience are more valuable than generalities about functional programming.

If the paper not only describes experience but also presents new technical results, or if the experience refutes cherished beliefs of the functional-programming community, it may be better to submit it as a full paper, which will be judged by the usual criteria of novelty, originality, and relevance. The Program Chair will be happy to advise on any concerns about which category to submit to.

About PACMPL

Proceedings of the ACM on Programming Languages (PACMPL https://pacmpl.acm.org/) is a Gold Open Access journal publishing research on all aspects of programming languages, from design to implementation and from mathematical formalisms to empirical studies. Each issue of the journal is devoted to a particular subject area within programming languages and will be announced through publicised Calls for Papers, like this one.