diff --git a/R/construct_repair.R b/R/construct_repair.R
new file mode 100644
index 00000000..9acee103
--- /dev/null
+++ b/R/construct_repair.R
@@ -0,0 +1,117 @@
+# FIXME: append() scrapes the class and attributes
+#   we might use an append replacement depending on the class
+#   or we just reconstruct all attrs after append(), but this might not be very minimal
+
+construct_repair <- function(target, ref) {
+  ref_code <- deparse_call(substitute(ref))
+  calls <- rec(target, ref, template = NULL)
+  code <- pipe(ref_code, calls, pipe = "magrittr", one_liner = FALSE)
+  code[[length(code)]] <- sub(" %>%$", "", code[[length(code)]])
+  styler::style_text(code)
+}
+
+#TODO
+
+rec <- function(target, ref, ind = NULL, ...) {
+
+  # remove or add at top level
+  l_target <- length(target)
+  l_ref <-  length(ref)
+  attrs_ref <- attributes(ref)
+  attrs_target <- attributes(target)
+  attrs_ref$names <- NULL
+  attrs_target$names <- NULL
+  n_common <- min(l_target, l_ref)
+  calls <- character()
+
+  # FIXME: we might make this a unlist(sapply()) once we return rather than print
+  for (i in seq_len(n_common)) {
+    if (!identical(target[[i]], ref[[i]])) {
+      if (!is.list(target[[i]]) || !is.list(ref[[i]])) {
+        # FIXME: deal with the case where only attributes need to be repaired
+        ind_code <- construct_raw(c(ind, i), ...)
+        target_code <- construct_raw(target[[i]], ...)
+        target_code <- paste0("~", target_code)
+        call <- construct_apply(list(ind_code, target_code), "purrr::modify_in", language = TRUE, ...)
+        calls <- c(calls, pipe(call, NULL, pipe = "magrittr", one_liner = FALSE))
+      } else {
+        call <- rec(target[[i]], ref[[i]] , c(ind, i), ...)
+        calls <- c(call, calls)
+      }
+    }
+  }
+
+  if (l_ref > l_target) {
+    # remove
+    for (i in (l_target + 1):l_ref) {
+      ind_code <- construct_raw(c(ind, i), ...)
+      target_code <- "~NULL"
+      calls <- construct_apply(list(ind_code, target_code), "purrr::modify_in", language = TRUE, ...)
+      calls <- c(calls, pipe(call, NULL, pipe = "magrittr", one_liner = FALSE))
+    }
+  }
+
+  if (l_target > l_ref) {
+    for (i in (l_ref + 1):l_target) {
+      if (is.null(ind)) {
+        call <- construct_apply(list(target[i]), "append", ...)
+      } else {
+        # ind_code <- construct_raw(c(ind, i), ...)
+        # target_code <- construct_raw(target[[i]], ...)
+        call <- construct_apply(list(c(ind, i), "append", target[i]), "purrr::modify_in", ...)
+      }
+      calls <- c(calls, pipe(call, NULL, pipe = "magrittr", one_liner = FALSE))
+    }
+    if(!identical(names(ref), names(target)[seq_along(ref)])) {
+      if (is.null(ind)) {
+        call <- construct_apply(list(names(target)[seq_along(ref)]), "setNames", ...)
+      } else {
+        call <- construct_apply(list(ind, "setNames", names(target)[seq_along(ref)]), "purrr::modify_in", ...)
+      }
+      calls <- c(calls, pipe(call, NULL, pipe = "magrittr", one_liner = FALSE))
+    }
+  }
+
+  if (!identical(attrs_ref, attrs_target)) {
+    # we loop through the args and ignore as long as they are the same and named identically
+    for (i in seq_along(attrs_target)) {
+      if (identical(names(attrs_target)[[1]], names(attrs_ref)[[1]]) &&
+          identical(attrs_target[[i]], attrs_ref[[i]])) {
+        attrs_target[[i]] <- NULL
+        attrs_ref[[i]] <- NULL
+      } else {
+        break
+      }
+    }
+    # attributes to remove from ref
+    if (length(attrs_ref)) {
+      attrs_ref[] <- list(NULL)
+    }
+    attrs <- c(attrs_ref, attrs_target)
+
+    if (is.null(ind)) {
+      call <- construct_apply(attrs, "structure", ...)
+    } else {
+      call <- construct_apply(c(list(ind), "structure", attrs), "purrr::modify_in", ...)
+    }
+    calls <- c(calls, pipe(call, NULL, pipe = "magrittr", one_liner = FALSE))
+  }
+
+  calls
+}
+
+# foo <- list(1)
+# attributes(foo) <- list(a1=1,a2=2)
+# bar <- list(1)
+# attributes(bar) <- list(a1=1,a3=2)
+# x <- list(foo)
+# y <- list(bar)
+# construct_repair(x, y)
+# x <- list(a=1, b= list(u =2, v = 3))
+# y <- list(a=1, b= data.frame(u =2, v = 3))
+# y <-  list(a=1, b= list(u =2, v = factor("c", levels = letters[1:3])))
+# y <-  list(a=1)
+# y <-  list(a=1, b = 3, c = )
+#
+#
+# construct_repair(x, y)