new files

Task/Ackermann-function/Tcl/ackermann-function-1.tcl

@@ -0,0 +1,9 @@
+proc ack {m n} {
+    if {$m == 0} {
+        expr {$n + 1}
+    } elseif {$n == 0} {
+        ack [expr {$m - 1}] 1
+    } else {
+        ack [expr {$m - 1}] [ack $m [expr {$n - 1}]]
+    }
+}

Task/Ackermann-function/Tcl/ackermann-function-2.tcl

@@ -0,0 +1,9 @@
+proc ack {m n} {
+    if {$m == 0} {
+        expr {$n + 1}
+    } elseif {$n == 0} {
+        tailcall ack [expr {$m - 1}] 1
+    } else {
+        tailcall ack [expr {$m - 1}] [ack $m [expr {$n - 1}]]
+    }
+}

Task/Ackermann-function/Tcl/ackermann-function-3.tcl

@@ -0,0 +1,55 @@
+package require Tcl 8.6
+
+# A memoization engine, from http://wiki.tcl.tk/18152
+oo::class create cache {
+    filter Memoize
+    variable ValueCache
+    method Memoize args {
+        # Do not filter the core method implementations
+        if {[lindex [self target] 0] eq "::oo::object"} {
+            return [next {*}$args]
+        }
+
+        # Check if the value is already in the cache
+        set key [self target],$args
+        if {[info exist ValueCache($key)]} {
+            return $ValueCache($key)
+        }
+
+        # Compute value, insert into cache, and return it
+        return [set ValueCache($key) [next {*}$args]]
+    }
+    method flushCache {} {
+        unset ValueCache
+        # Skip the cacheing
+        return -level 2 ""
+    }
+}
+
+# Make an object, attach the cache engine to it, and define ack as a method
+oo::object create cached
+oo::objdefine cached {
+    mixin cache
+    method ack {m n} {
+        if {$m==0} {
+            expr {$n+1}
+        } elseif {$m==1} {
+            # From the Mathematica version
+            expr {$m+2}
+        } elseif {$m==2} {
+            # From the Mathematica version
+            expr {2*$n+3}
+        } elseif {$m==3} {
+            # From the Mathematica version
+            expr {8*(2**$n-1)+5}
+        } elseif {$n==0} {
+            tailcall my ack [expr {$m-1}] 1
+        } else {
+            tailcall my ack [expr {$m-1}] [my ack $m [expr {$n-1}]]
+        }
+    }
+}
+
+# Some small tweaks...
+interp recursionlimit {} 100000
+interp alias {} ack {} cacheable ack