I think I'm pretty much doing pi approximations in every language now, so, here it is in F#!
The interesting thing about F# is that, while a functional language, it is actually quite like R which is not functional.
I still have the same issue with NASM and am working on that one side-by-side with the other languages. If you can help fix the issue, please let me know at https://repl.it/talk/ask/NASM-Print-Floating-Point/41105.
Here are the other approximations so far:
Lua - https://repl.it/talk/share/p-in-Lua/41251
Dart - https://repl.it/talk/share/p-in-Dart/41240
R - https://repl.it/talk/share/p-in-R/41205
Haskell - https://repl.it/talk/share/p-in-Haskell/41199
Raku - https://repl.it/talk/share/p-in-Raku/41111
Rust - https://repl.it/talk/share/p-in-Rust/41056
Go - https://repl.it/talk/share/p-in-Go/40950
Swift - https://repl.it/talk/share/p-in-Swift/36150
C# - https://repl.it/talk/share/p-in-C/36141
Bash - https://repl.it/talk/share/p-in-Bash/36133
Kotlin - https://repl.it/talk/share/p-in-Kotlin/36125
Ruby - https://repl.it/talk/share/p-in-Ruby/34982
Java - https://repl.it/talk/share/p-in-Java/34978
QBasic - https://repl.it/talk/share/p-in-QBasic/34973
Fortran - https://repl.it/talk/share/p-in-Fortran/34890
APL - https://repl.it/talk/share/p-in-APL/34888
Forth - https://repl.it/talk/share/p-in-Forth/34652
LOLCODE - https://repl.it/talk/share/p-in-LOLCODE/34421
Python and Node.js (Node is linked in post) - https://repl.it/talk/share/2-Approximations-of-p-In-Only-Four-Lines-of-Code/32773
C - https://repl.it/talk/share/p-Approximations-in-C/33461
Credit to @NoelBryan, @TheForArkLD , @Warhawk947 , and @LizFoster for inspiring these approximations. Most of these use the Nilakantha Series, although I also use the arctangent method (multiplying the radian arctangent of 1 by 4 to get pi and getting the arctangent with an infinite series) in three of them (Python, Node, and C).
Also, credit to @Jakman for suggesting F#!
Next up is Crystal and then L ( @theangryepicbanana 's language). (I'm still working on NASM, but can't really tell when I'll be able to get that one done.) If you have any suggestions for after those, please let me know!