Coend

[bond15]

Should the Set-Coend go in a separate "Instances" file?

[maxsnew]

Looks good except for minor notational comments. Also fix the line lengths and white space. You can just run the fix-whitespace utility (cabal install fix-whitespace to install IIRC)

[bond15]

@maxsnew
So should I scrap this and use a similar construction to your definition of Ends ?

[maxsnew]

Typically we would have two versions: one concrete like yours which is easy to read and understand and one compositional like mine where it's easier to get common properties. Then we would define a function that goes from the concrete to the compositional one.

[bond15]

Typically we would have two versions: one concrete like yours which is easy to read and understand and one compositional like mine where it's easier to get common properties. Then we would define a function that goes from the concrete to the compositional one.

I can attempt this once both branches are merged in.