[Haskell-cafe] What is the meaning of tilde ("~") symbol

[Andrew Coppin]

Here's an idea... maybe we should make a small page on the Wiki 
explaining what all the various symbols in Haskell mean?

There are a couple which are rare enough that most tutorials don't 
mention them that often. And there are of course symbols which mean 
different things in different contexts. (I especially love how curly 
braces are used for overriding layout *and* for named fields...)