I was only wondering why doesn't that work. The two functions were just an example of how I thought OverloadedLists should/could work. I got an answer on irc that ':' constructor is not desugared, but I expected it is. Compiler can see when overloading is for "real" list and skip it, preserving performance.

-------- Original Message -------- Subject: Re: [Haskell-cafe] Pattern matching with OverloadedLists From: Alejandro Serrano Mena To: vlatko.basic@gmail.com Cc: haskell-cafe Date: 06/11/15 16:38

You need to write `toList` in both branches:

f (toList -> ('9':_)) = 1 f (toList -> ('1':_)) = 2

2015-11-06 16:20 GMT+01:00 Vlatko Basic mailto:vlatko.basic@gmail.com>:

Hello Cafe,

wiki for OverloadedLists says that

g [x,y,z] = ...

is treated as

g (toList-> [x,y,z]) =

Shouldn't this work? Both 'f's should be treated the same.

f :: Text -> Int f (toList -> ('9':_)) = 1 -- OK f ('1':_) = 2 -- Couldn't match expected type ‘Text’ with actual type ‘[Char]’

(OverloadedStrings is also on)

Am I missing something?

br, vlatko

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