Merge pull request #597 from olafurpg/gsoc-scalafmt

Add abstract for scalafmt gsoc project

Author: julienrf

gsoc/2017.md

@@ -184,6 +184,24 @@ the JVM) and web-based visualization libraries such as d3.
 
 Supervised by [@julienrf](https://github.com/julienrf)
 
+### New line-wrapping algorithm for scalafmt
+
+[Scalafmt](https://olafurpg.github.io/scalafmt/) is a code formatter for Scala.
+A key feature of scalafmt is that users can define a maximum width (for example 80 characters)
+so that long code lines get automatically wrapped into shorter lines.
+Currently, scalafmt uses a [token-based best-first search algorithm](https://geirsson.com/assets/olafur.geirsson-scalafmt-thesis.pdf) to wrap long lines.
+Both [dartfmt](http://journal.stuffwithstuff.com/2015/09/08/the-hardest-program-ive-ever-written/)
+and [clang-format](https://www.youtube.com/watch?v=s7JmdCfI__c) use a similar approach.
+This token-based best-first algorithm has [known issues](https://olafurpg.github.io/scalafmt/#Deeplynestedcode) in scalafmt.
+
+The goal of this project would be to explore and implement an alternative line wrapping algorithm for scalafmt.
+One promising alternative is the [dynamic-programming algorithm employed by rfmt](https://www.researchgate.net/profile/Phillip_Yelland/publication/284724851_A_New_Approach_to_Optimal_Code_Formatting/links/5657f1e608ae4988a7b58558.pdf)
+(see [Python implementation](https://github.com/google/rfmt)).
+Another promising algorithm is Philip Wadler's ["prettier printer"](http://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf).
+The prettier-printer algorithm has been successfully employed by the [prettier](https://github.com/jlongster/prettier) JavaScript formatter.
+
+Supervised by [@olafurpg](https://github.com/olafurpg)
+
 *... Mentors: please insert your projects here. You can use the following template and submit a PR [here](https://github.com/scala/scala-lang). Note that student applications will end on April 3, 2017 ...*
 
 ### *Project name*