Add support for title-casing letters (bug#24603)

* src/casefiddle.c (struct casing_context, prepare_casing_context): Add
titlecase_char_table member.  It’s set to the ‘titlecase’ Unicode
property table if capitalisation has been requested.
(case_character): Make use of the titlecase_char_table to title-case
initial characters when capitalising.

* test/src/casefiddle-tests.el (casefiddle-tests--characters,
casefiddle-tests-casing): Update test cases which are now passing.

1 files changed, 26 insertions, 13 deletions

diff --git a/test/src/casefiddle-tests.el b/test/src/casefiddle-tests.el
index 152d85de006..e83cb00059b 100644
--- a/test/src/casefiddle-tests.el
+++ b/test/src/casefiddle-tests.el
@@ -63,13 +63,9 @@
     (?Ł ?Ł ?ł ?Ł)
     (?ł ?Ł ?ł ?Ł)
 
-    ;; FIXME(bug#24603): Commented ones are what we want.
-    ;;(?DŽ ?DŽ ?dž ?Dž)
-    (?DŽ ?DŽ ?dž ?DŽ)
-    ;;(?Dž ?DŽ ?dž ?Dž)
-    (?Dž ?DŽ ?dž ?DŽ)
-    ;;(?dž ?DŽ ?dž ?Dž)
-    (?dž ?DŽ ?dž ?DŽ)
+    (?DŽ ?DŽ ?dž ?Dž)
+    (?Dž ?DŽ ?dž ?Dž)
+    (?dž ?DŽ ?dž ?Dž)
 
     (?Σ ?Σ ?σ ?Σ)
     (?σ ?Σ ?σ ?Σ)
@@ -186,19 +182,19 @@
       ;; input     upper     lower    capitalize up-initials
       '(("Foo baR" "FOO BAR" "foo bar" "Foo Bar" "Foo BaR")
         ("Ⅷ ⅷ" "Ⅷ Ⅷ" "ⅷ ⅷ" "Ⅷ Ⅷ" "Ⅷ Ⅷ")
+        ;; "DžUNGLA" is an unfortunate result but it’s really best we can
+        ;; do while still being consistent.  Hopefully, users only ever
+        ;; use upcase-initials on camelCase identifiers not real words.
+        ("DŽUNGLA" "DŽUNGLA" "džungla" "Džungla" "DžUNGLA")
+        ("Džungla" "DŽUNGLA" "džungla" "Džungla" "Džungla")
+        ("džungla" "DŽUNGLA" "džungla" "Džungla" "Džungla")
         ;; FIXME(bug#24603): Everything below is broken at the moment.
         ;; Here’s what should happen:
-        ;;("DŽUNGLA" "DŽUNGLA" "džungla" "Džungla" "DžUNGLA")
-        ;;("Džungla" "DŽUNGLA" "džungla" "Džungla" "Džungla")
-        ;;("džungla" "DŽUNGLA" "džungla" "Džungla" "Džungla")
         ;;("define" "DEFINE" "define" "Define" "Define")
         ;;("fish" "FIsh" "fish" "Fish" "Fish")
         ;;("Straße" "STRASSE" "straße" "Straße" "Straße")
         ;;("ΌΣΟΣ" "ΌΣΟΣ" "όσος" "Όσος" "Όσος")
         ;; And here’s what is actually happening:
-        ("DŽUNGLA" "DŽUNGLA" "džungla" "DŽungla" "DŽUNGLA")
-        ("Džungla" "DŽUNGLA" "džungla" "DŽungla" "DŽungla")
-        ("džungla" "DŽUNGLA" "džungla" "DŽungla" "DŽungla")
         ("define" "DEfiNE" "define" "Define" "Define")
         ("fish" "fiSH" "fish" "fish" "fish")
         ("Straße" "STRAßE" "straße" "Straße" "Straße")
@@ -243,4 +239,21 @@
                 "\xef\xff\xef Zażółć GĘŚlą \xcf\xcf")))))))
 
 
+(ert-deftest casefiddle-tests-char-casing ()
+  ;;             input upcase downcase [titlecase]
+  (dolist (test '((?a ?A ?a) (?A ?A ?a)
+                  (?ł ?Ł ?ł) (?Ł ?Ł ?ł)
+                  (?ß ?ß ?ß) (?ẞ ?ẞ ?ß)
+                  (?ⅷ ?Ⅷ ?ⅷ) (?Ⅷ ?Ⅷ ?ⅷ)
+                  (?DŽ ?DŽ ?dž ?Dž) (?Dž ?DŽ ?dž ?Dž) (?dž ?DŽ ?dž ?Dž)))
+    (let ((ch (car test))
+          (up (nth 1 test))
+          (lo (nth 2 test))
+          (tc (or (nth 3 test) (nth 1 test))))
+      (should (eq up (upcase ch)))
+      (should (eq lo (downcase ch)))
+      (should (eq tc (capitalize ch)))
+      (should (eq tc (upcase-initials ch))))))
+
+
 ;;; casefiddle-tests.el ends here