When WebSharper compiles F# to JavaScript it preserves namespaces, module and class nesting to make it easy to navigate the compiled code from JavaScript shell. Roughly speaking, A.B.C.D.E identifier in F# can be found by typing A.B.C.D.E in JavaScript. This poses a challenge: as you can imagine, emitting long qualified identifiers everywhere is not a good idea for compact code generation. To save space WebSharper 2.4 does class/module interning. The basic idea is to say L=Microsoft.FSharp.Core.ListMod[...]

Can anyone explain why this code leaks memory? Looks like using Async.StartAsTask makes it complete in constant space.

Recent FPish FPish discussion focused on some hacks available in F# to write code that resembles using Haskell type classes. I particularly enjoyed the comments by Gustavo Leon and Loic Denuziere. To cut the long story short, before compiling to .NET F# expands methods delcared inline and does overload resolution. This was intended to support flexible operator overloading, but opens up the door for interesting hacks. Even code that generalizes over higher kinds and therefore cannot exist at .NET level [...]

In this article I discuss why F# Async is a good thing for writing concurrent software on .NET and show how to implement your own Async specialized for low-concurrency use. As a sample application, I look at a simple CML-style blocking channel. 30-50 lines of custom async and threadpool implementation increase the throughput from 100-400 K to 1M messages a second. Concurrency? Again? It is hard to believe that after so many man-years of computer science research anyone would still ha[...]

I found some more time to study Coq. One place where I stumble very frequently is case analysis of value-indexed inductive types. There are often cases that lead to contradiction. Other cases intuitively imply some variables to be equal. Vanilla match constructs gives you no help, leaving you stranded. In proof mode, inversion tactic helps a lot. However, generated proofs are huge and hard to navigate. Another option is to use dependent pattern matching directly (which is what inversion generates for[...]