Data update

Task/ISBN13-check-digit/Langur/isbn13-check-digit.langur

@@ -1,18 +1,18 @@
-val .isbn13checkdigit = fn(var .s) {
-    .s = replace(.s, RE/[\- ]/)
-    .s -> re/^[0-9]{13}$/ and
-        fold(fn{+}, map [_, fn{*3}], s2n .s) div 10
+val isbn13checkdigit = fn(var s) {
+    s = replace(s, RE/[\- ]/)
+    s -> re/^[0-9]{13}$/ and
+        fold(fn{+}, map([_, fn{*3}], s2n(s))) div 10
 }
 
-val .tests = h{
+val tests = {
     "978-0596528126": true,
     "978-0596528120": false,
     "978-1788399081": true,
     "978-1788399083": false,
 }
 
-for .key of .tests {
-    val .pass = .isbn13checkdigit(.key)
-    write .key, ": ", if(.pass: "good"; "bad")
-    writeln if(.pass == .tests[.key]: ""; " (ISBN-13 CHECK DIGIT TEST FAILED)")
+for key of tests {
+    val pass = isbn13checkdigit(key)
+    write key, ": ", if(pass: "good"; "bad")
+    writeln if(pass == tests[key]: ""; " (ISBN-13 CHECK DIGIT TEST FAILED)")
 }

Task/ISBN13-check-digit/Standard-ML/isbn13-check-digit-1.ml

@@ -0,0 +1,22 @@
+(* these type decorations are optional, you could just as well put:
+  fun isValidISBN s =
+*)
+fun isValidISBN (s : string) : bool =
+  let
+    val digits = List.filter Char.isDigit (explode s)
+    val nums = map (fn x => ord x - ord #"0") digits
+    val len = length nums
+    fun sumISBN [] = raise Domain
+      | sumISBN [x] = x
+      | sumISBN (x1::x2::xs) = x1 + 3*x2 + sumISBN xs
+  in
+    len = 13 andalso sumISBN nums mod 10 = 0
+  end
+
+val test = ["978-1734314502", "978-1734314509",
+            "978-1788399081", "978-1788399083"]
+
+fun printTest (s : string) : unit =
+  (print s; print (if isValidISBN s then ": good\n" else ": bad\n"))
+
+fun main () = app printTest test

Task/ISBN13-check-digit/Standard-ML/isbn13-check-digit-2.ml

@@ -1,4 +1,4 @@
-local
+let
   fun check (c, p as (m, n)) =
     if Char.isDigit c then
       (not m, (if m then 3 * (ord c - 48) else ord c - 48) + n)