NEWS: add news for 2.7.0

NEWS

@@ -1,3 +1,51 @@
+2.7.0 (April 19, 2024)
+----------------------
+
+This release marks a major improvement in Enchant’s maintainability: the
+main library has been translated into Vala, a modern object-oriented
+language with automatic memory management that, like Enchant, is based on
+GLib.
+
+Developers and packagers need not worry: this release is API and
+ABI-compatible with previous releases (with some minor changes, noted below,
+that is unrelated to the use of Vala), and you do not even need a Vala
+compiler to build it, thanks to Automake, which distributes the C source
+files generated by the Vala compiler. The build-time and run-time
+dependencies therefore remain unchanged.
+
+The library code is 33% smaller, and the total code-base has reduced
+by 12%. Thanks in particular to Vala’s more modern string and collection
+handling, I anticipate it being much easier to add functionality in future.
+The use of Vala may also be extended in future to those provider back-ends
+written in C.
+
+The provider API is now declared private. No third-party providers have been
+available for Enchant for many years to my knowledge, and the only new
+provider in the last ten years, Nuspell, was implemented by Nuspell’s
+authors in Enchant. The provider interface has changed in this release; and
+of course all the current providers have been updated, including the
+still-experimental Zemberek provider.
+
+There is a small change to the semantics of dictionaries: in the past,
+requesting a dictionary with the same language tag twice from a given
+provider returned the same dictionary object. This is no longer the case.
+This allows an application to have multiple active spelling sessions with
+the same broker object in any given language. Applications that relied on
+this functionality must in future keep track of the identity of spelling
+sessions themselves. I do not regard this as an API/ABI change, since it was
+only documented in a vague way by saying that dictionaries were
+“reference-counted”. This language has been removed from the documentation.
+
+Finally, a big thank-you to Eric Scott Albright, who wrote the test suite,
+and SIL, for funding his work. Enchant has an excellent test suite; one of
+my first contributions to the project was to get the test suite running on
+all platforms, as it was originally written just for Windows. It’s an
+impressive set of tests that covers a huge range of normal and edge cases,
+and has often saved me before now; but it has never been more valuable than
+when rewriting the entire core library. Hopefully it has kept the number of
+new bugs I’ve introduced to a minimum!
+
+
 2.6.9 (April 4, 2024)
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