2017-04-16 17:21 GMT+02:00 Vassil Ognyanov Keremidchiev
1) It's not a problem, it's a improvement in syntax with lowering verbosity.
If it's not a real problem, it probably shouldn't be done: Every tiny change in the syntax, even if it's somehow backwards compatible, has a high cost in the whole ecosystem: The compiler has to be changed (probably by far the easiest part), libraries for parsing/pretty-printing Haskell have to be adapted, Editors/syntax highlighting rules have to be changed, books/tutorials have to be rewritten and people have to be retrained (yes, even if they don't use the new syntax: others might use it). To outweigh this pain, there should be be a real gain, saving just 4 keystrokes isn't worth it. And for me, and probably others, it's not an improvement in syntax, it actually makes things worse by removing a syntactic cue.
It's similar with the difference between Pascal and C syntax. One of the reasons we all love Haskell is because it's not so verbose.
I think it's actually not the non-verbosity which makes Haskell attractive, it's its expressiveness. These are two quite different things.
I have asked often why do-block is so different, than non-do-block.
Because it is fundamentally different from the rest, having a sequential nature (for some meaning of "sequential" given by the underlying monad).
Exchanging "x = foo" with "x <- foo" will result in error, so there is no problem that the difference is small.
Of course a machine will see the difference easily and immediately, the question is: Will people do so, too?
2) you're right. May be lazyness could solve that? I'm not sure here.
So what are the desugaring rules for your proposal? I have the gut feeling that they will be quite a bit more complicated and non-local than the current ones. Remember the famous quote: "If you can't explain it to a six year old, you don't understand it yourself." ;-)