Data commit

Task/Roman-numerals-Decode/XQuery/roman-numerals-decode.xquery

@@ -0,0 +1,47 @@
+xquery version "3.1";
+
+declare function local:decode-roman-numeral($roman-numeral as xs:string) {
+    $roman-numeral
+    => upper-case()
+    => for-each(
+        function($roman-numeral-uppercase) {
+            analyze-string($roman-numeral-uppercase, ".")/fn:match
+            ! map { "M": 1000, "D": 500, "C": 100, "L": 50, "X": 10, "V": 5, "I": 1 }(.)
+        }
+    )
+    => fold-right([0,0],
+        function($number as xs:integer, $accumulator as array(*)) {
+            let $running-total := $accumulator?1
+            let $previous-number := $accumulator?2
+            return
+                if ($number lt $previous-number) then
+                    [ $running-total - $number, $number ]
+                else
+                    [ $running-total + $number, $number ]
+        }
+    )
+    => array:get(1)
+};
+
+let $roman-numerals :=
+    map {
+        "MCMXCIX": 1999,
+        "MDCLXVI": 1666,
+        "XXV": 25,
+        "XIX": 19,
+        "XI": 11,
+        "CMLIV": 954,
+        "MMXI": 2011,
+        "CD": 400,
+        "MCMXC": 1990,
+        "MMVIII": 2008,
+        "MMIX": 2009,
+        "MMMDCCCLXXXVIII": 3888
+    }
+return
+    map:for-each(
+        $roman-numerals,
+        function($roman-numeral, $expected-value) {
+            local:decode-roman-numeral($roman-numeral) eq $expected-value
+        }
+    )