Initial data commit

Task/String-case/Tcl/string-case.tcl

@@ -0,0 +1,30 @@
+set string alphaBETA
+
+# three built-in case conversion commands
+string toupper $string  ;# ==> ALPHABETA
+string tolower $string  ;# ==> alphabeta
+string totitle $string  ;# ==> Alphabeta
+
+# not built-in
+proc swapcase {s} {
+    foreach char [split $s ""] {
+        if {$char eq [set CHAR [string toupper $char]]} {
+            append new [string tolower $char]
+        } else {
+            append new $CHAR
+        }
+    }
+    return $new
+}
+swapcase $string  ;# ==> ALPHAbeta
+
+# better performance, but English alphabet only
+proc swapcase_en {s} {
+    string map {
+        a A b B c C d D e E f F g G h H i I j J k K l L m M n N o O p P q Q r R s S t T u U v V w W x X y Y z Z
+        A a B b C c D d E e F f G g H h I i J j K k L l M m N n O o P p Q q R r S s T t U u V v W w X x Y y Z z
+    } $s
+}
+
+swapcase Père     ;# ==> pÈRE
+swapcase_en Père  ;# ==> pèRE