Updatre NEWS.md for 0.5.0

NEWS.md

@@ -1,3 +1,31 @@
+# emld 0.5.0
+
+User-facing changes:
+
+- Rewrote logic around how `emld` works with `schemaLocation`:
+  - The `schemaLocation` argument on `as_xml` used to fill in a default value that pointed to a local copy of `eml.xsd`. Now, it automatically fills in a web-resolvable location to make validating documents easier out of the box. 
+
+  See [#44](https://github.com/ropensci/emld/issues/44) & [#45](https://github.com/ropensci/emld/issues/45).
+
+- Re-worked the logic for handling `schemaLocation` when serializing to XML:
+  - When `schemaLocation` is present on the `emld` object, it is used verbatim (no change in API here) regardless of the `schemaLocation` argument of `as_xml`.
+  - When `schemaLocation` is absent on the `emld` object:
+    - `as_xml(..., schemaLocation = TRUE)` causes a value to be guessed.
+    - `as_xml(..., schemaLocation = FALSE)` explicitly prevents a value from being filled in when serialized.
+    - `as_xml(..., schemaLocation = "Some value)` explicitly sets the provided value.
+
+  See [#44](https://github.com/ropensci/emld/issues/44) & [#45](https://github.com/ropensci/emld/issues/45).
+
+- `emld::eml_validate` no longer depends on `schemaLocation` to determine the correct XSD to use during schema validation and now uses two helpers (See below) to find the correct schema file. See [#52](https://github.com/ropensci/emld/issues/44) & [#45](https://github.com/ropensci/emld/issues/53).
+
+Developer-facing (non-exported) changes:
+
+- Added two new helper methods:
+  1. `find_real_root_name(doc : xml_document) : list(prefix : character, name: character)` which returns the namespace prefix and the local name of the root element on an `xml_document`.
+  2. `guess_root_schema(doc : xml_document) : list(module : character, version : character, namespace : character)` which returns the module, schema version, and namespace URI of the root element on an `xml_document`.
+- `schemaLocation` is now ignored during roundtrip testing because of the new (above) behavior of `emld` with respect to `schemaLocation`.
+- Roundtrip testing can now handle documents that are supposed to be invalid but still roundtripped. Specify intentionally invalid files by adding "invalid" (case insensitive) to the filename in `inst/tests`.
+
 # emld 0.4.0
 
 - Fixed serialization bug for `references` attributes [#48](https://github.com/ropensci/emld/issues/48)