Add lua as an internal library in libs/lua

1 files changed, 40 insertions, 0 deletions

diff --git a/libs/lua/test/fib.lua b/libs/lua/test/fib.lua
new file mode 100644
index 0000000..97a921b
--- /dev/null
+++ b/libs/lua/test/fib.lua
@@ -0,0 +1,40 @@
+-- fibonacci function with cache
+
+-- very inefficient fibonacci function
+function fib(n)
+        N=N+1
+        if n<2 then
+                return n
+        else
+                return fib(n-1)+fib(n-2)
+        end
+end
+
+-- a general-purpose value cache
+function cache(f)
+        local c={}
+        return function (x)
+                local y=c[x]
+                if not y then
+                        y=f(x)
+                        c[x]=y
+                end
+                return y
+        end
+end
+
+-- run and time it
+function test(s,f)
+        N=0
+        local c=os.clock()
+        local v=f(n)
+        local t=os.clock()-c
+        print(s,n,v,t,N)
+end
+
+n=arg[1] or 24          -- for other values, do lua fib.lua XX
+n=tonumber(n)
+print("","n","value","time","evals")
+test("plain",fib)
+fib=cache(fib)
+test("cached",fib)