lookup f >>= \expected ->
let accST = (\(s,ts,es) e->infer e >>= \(s_,et,e_)-> pure (compose s_ s,ts++[et],es++[e_])) in
foldM accST (zero,[],[]) args >>= \(s1, argTs, args_)->
lookup f >>= \expected ->
let accST = (\(s,ts,es) e->infer e >>= \(s_,et,e_)-> pure (compose s_ s,ts++[et],es++[e_])) in
foldM accST (zero,[],[]) args >>= \(s1, argTs, args_)->