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 <trupill@gmail.com>
To: vlatko.basic@gmail.com
Cc: haskell-cafe <Haskell-cafe@haskell.org>
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 <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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