py_to_r method for keras SharedObjectConfig

Author: t-kalinowski

NAMESPACE

@@ -14,6 +14,7 @@ S3method(print,keras_training_history)
 S3method(print,kerastools.model.RModel)
 S3method(print,py_R6ClassGenerator)
 S3method(py_str,keras.engine.training.Model)
+S3method(py_to_r,keras.utils.generic_utils.SharedObjectConfig)
 S3method(py_to_r_wrapper,keras.engine.base_layer.Layer)
 S3method(py_to_r_wrapper,keras.engine.training.Model)
 S3method(py_to_r_wrapper,kerastools.model.RModel)

NEWS.md

@@ -12,6 +12,9 @@
     layer_add(block_1_output)
   ```
 
+- `model$get_config()` method now returns an R object that can be safely serialized 
+  to rds.
+
 # keras 2.9.0
 
 - New functions for constructing custom keras subclasses:

R/layer-methods.R

@@ -38,12 +38,27 @@ get_config <- function(object) {
   config
 }
 
+# model$get_config() returns a nested object of list/dicts, but the contract
+# is that the object is serializable to json, which means that once
+# reticulate conversion rules are redone, the config will be guaranteed to be safe
+# to convert to R and back.
+
+# this py_to_r method is so that model$get_config() can return a pure R object.
+# A keras SharedObjectConfig is a keras dictionary
+#' @export
+py_to_r.keras.utils.generic_utils.SharedObjectConfig <- function(x) {
+  import_builtins()$dict(x)
+}
+
 
 #' @rdname get_config
 #' @export
-from_config <- function(config) {
-  class <- attr(config, "config_class")
-  class$from_config(config)
+from_config <- function(config, custom_objects = NULL) {
+  class <- attr(config, "config_class") %||% keras$Model
+  args <- list(config)
+  if(length(custom_objects))
+    args[[2L]] <- objects_with_py_function_names(custom_objects)
+  do.call(class$from_config, args)
 }
 
 #' Layer/Model weights as R arrays