Changed . token to _dot

This change allows the dotfiles to work with chezmoi (e.g: on windows)
and improves grepability with neovim/telescope

dot_config/nushell/nu_scripts/modules/recursion/fib.nu

@@ -0,0 +1,48 @@
+# Recursive Fibonacci programs in Nu
+
+# Returns the Fibonacci number of its input n.
+# This version is non-tail call optimized and might consume large values
+# of stack space even for small values of n. It is also not memoized so run time
+# performance for even quite small values of N is very poor.
+def fib-nontail [n: int] -> int {
+  if $n == 0 {
+  0
+  } else if $n == 1 {
+    1
+  } else {
+    (fib-nontail ($n - 2)) + (fib-nontail ($n - 1))
+  }
+}
+
+
+
+
+
+
+# Returns the Fibonacci number for the index n. Uses the double APS method to
+# ensure the recursive call is in thetail position.
+def fib-aps [n: int, acc: int=1, accp: int=1] -> int {
+  if ($n == 0) or ($n == 1) {
+    $n
+  } else if $n == 2 {
+    $acc
+  } else {
+    fib-aps ($n - 1) ($acc + $accp) $acc
+  }
+}
+
+
+
+# Return the Fibonacci number for given index n
+# This version relies on the trampoline helper
+def fib [n: int, acc: int=1, accp: int=1] -> int {
+  if ($n == 0) or ($n == 1) {
+    $n
+  } else if $n == 2 {
+    $acc
+  } else {
+    {|| fib ($n - 1) ($acc + $accp) $acc }
+  }
+}
+
+