rename unwrap_wirtinger -> unthunk

Author: simeonschaub

src/differentials.jl

@@ -47,8 +47,6 @@ wrapped by `x`, such that mutating `extern(x)` might mutate `x` itself.
 
 abstract type AbstractWirtinger <: AbstractDifferential end
 
-unwrap_wirtinger(x) = x
-
 wirtinger_primal(x) = x
 wirtinger_conjugate(::Any) = Zero()
 
@@ -209,12 +207,13 @@ end
     return element, (externed, new_state)
 end
 
-unwrap_wirtinger(x::Union{Casted,AbstractThunk}) = unwrap_wirtinger(extern(x))
+unthunk(x) = x
+unthunk(x::AbstractThunk) = unthunk(x())
 
-wirtinger_primal(x::Union{Casted,AbstractThunk}) =
-    throw(ArgumentError("`wirtinger_primal` is not defined for $(typeof(x)). Call `unwrap_wirtinger` first"))
-wirtinger_primal(x::Union{Casted,AbstractThunk}) =
-    throw(ArgumentError("`wirtinger_conjugate` is not defined for $(typeof(x)). Call `unwrap_wirtinger` first"))
+wirtinger_primal(::Union{AbstractThunk}) =
+    throw(ArgumentError("`wirtinger_primal` is not defined for `AbstractThunk`. Call `unthunk` first."))
+wirtinger_conjugate(::Union{AbstractThunk}) =
+    throw(ArgumentError("`wirtinger_primal` is not defined for `AbstractThunk`. Call `unthunk` first."))
 
 #####
 ##### `Thunk`