Types

Shell Types

• Shell :: * -> * -- a top-level effect
• Transform :: * -> * -> * -- a transformation
• Rewrite :: * -> * -- a transformation from something to something of the same type
• Name :: * -- name of a binder

Examples

• display :: Shell ()
• try :: Rewrite a -> Rewrite a
• idR :: Rewrite a
• rewrite :: Rewrite ? -> Shell ()
• query :: Transformation ? b -> Shell b

Running things

Some functions directly use Shell:

HERMIT> display

Others need promotion functions:

HERMIT> rewrite (try idR)

Others need

HERMIT> query (...)

And other