yogsototh/snoyman.com-content
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Last minute changes

Browse source
This commit is contained in:
Michael Snoyman 2017-10-27 14:23:37 +02:00
parent 234ac63b19
commit 5033b49946
No known key found for this signature in database
GPG key ID: A048E8C057E86876
1 changed files with 5 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
reveal/monad-transformer-state.md
View file

@ -289,7 +289,7 @@ Next: let's define those classes
## But does it lift?
Which of these functions can be safely converted to `StateT s IO`?
Which of these functions can be converted to `StateT s IO` with `lift`?
```haskell
putStrLn :: String -> IO a
@ -320,6 +320,7 @@ newtype ExceptT e m a = ExceptT ( m (Either e a))
## Unlifting
* Also a made up term :)
* Unlifting is taking a control operation living in `IO` and moving it
into a transformer
* Transformers with no monadic state can safely "unlift" control
@ -431,6 +432,8 @@ But it's not exactly the type signature people expect.
Two basic approaches today for typeclass-based control function
lifting.
----
## exceptions
Define an `mtl`-style typeclass for each operation.
@ -487,7 +490,7 @@ recommendations:
* Feel free to use any monad transformer "in the small," where you're
not forking threads or acquiring resources
* Keep your overall applications to `ReaderT env IO`
* Keep your overall applications to `ReaderT env IO` (or use `RIO`)
Prepare torches and pitchforks for the next two slides
@ -511,7 +514,6 @@ Prepare torches and pitchforks for the next two slides
* But that's the Haskell runtime system
* Also, you have to deal with async exceptions anyway
* Caveat emptor: Many people disagree with me here
* I still think I'm right :)
---