March 2014 update

Task/Y-combinator/Objective-C/y-combinator.m

@@ -16,27 +16,27 @@ Func fix (FuncFunc f) {
 }
 
 int main (int argc, const char *argv[]) {
-  NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
+  @autoreleasepool {
 
-  FuncFunc almost_fac = ^Func(Func f) {
-    return [[^(int n) {
-      if (n <= 1) return 1;
-      return n * f(n - 1);
-    } copy] autorelease];
-  };
+    FuncFunc almost_fac = ^Func(Func f) {
+      return ^(int n) {
+        if (n <= 1) return 1;
+        return n * f(n - 1);
+      };
+    };
 
-  FuncFunc almost_fib = ^Func(Func f) {
-    return [[^(int n) {
-      if (n <= 2) return 1;
-      return  f(n - 1) + f(n - 2);
-    } copy] autorelease];
-  };
+    FuncFunc almost_fib = ^Func(Func f) {
+      return ^(int n) {
+        if (n <= 2) return 1;
+        return  f(n - 1) + f(n - 2);
+      };
+    };
 
-  Func fib = fix(almost_fib);
-  Func fac = fix(almost_fac);
-  NSLog(@"fib(10) = %d", fib(10));
-  NSLog(@"fac(10) = %d", fac(10));
+    Func fib = fix(almost_fib);
+    Func fac = fix(almost_fac);
+    NSLog(@"fib(10) = %d", fib(10));
+    NSLog(@"fac(10) = %d", fac(10));
 
-  [pool release];
+  }
   return 0;
 }

Task/Y-combinator/TXR/y-combinator.txr

@@ -0,0 +1,14 @@
+@(do
+  ;; The Y combinator:
+  (defun y (f)
+    [(op @1 @1)
+     (op f (op [@@1 @@1]))])
+
+  ;; The Y-combinator-based factorial:
+  (defun fac (f)
+    (do if (zerop @1)
+           1
+           (* @1 [f (- @1 1)])))
+
+  ;; Test:
+  (format t "~s\n" [[y fac] 4]))

Task/Y-combinator/XQuery/y-combinator-1.xquery

@@ -0,0 +1,9 @@
+let $Y := function($f) {
+    (function($x) { ($x)($x) })( function($g) { $f( (function($a) { $g($g) ($a)})  ) } )
+  }
+let $fac := $Y(function($f) { function($n) { if($n <  2) then 1  else $n * $f($n - 1) } })
+let $fib := $Y(function($f) { function($n) { if($n <= 1) then $n else $f($n - 1) + $f($n - 2) } })
+return (
+    $fac(6),
+    $fib(6)
+)

Task/Y-combinator/XQuery/y-combinator-2.xquery

@@ -0,0 +1 @@
+720 8