Consider using record syntax for the AST to reduce extra work when adding more fields

[anka-213]

For example, with this:

data FooBar
  = Foo {x :: Int, _y :: Char}
  | Bar {x :: Int}
  
 showFoo :: FooBar -> String
 showFoo Foo {_y = y} = "Foo with " ++ show y
 showFoo Bar {}       = "Not foo"

we could add any number of fields to Foo and Bar without having to modify showFoo at all.

[Martin-Strecker]

OK, I was not aware of that, looks useful, and we can generalize its use.

[mengwong]

similarly for annotations, we can have { getType : … , getPos : … }