diff options
Diffstat (limited to 'libs/lua-5.1.5/test/factorial.lua')
-rw-r--r-- | libs/lua-5.1.5/test/factorial.lua | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/libs/lua-5.1.5/test/factorial.lua b/libs/lua-5.1.5/test/factorial.lua new file mode 100644 index 0000000..7c4cf0f --- /dev/null +++ b/libs/lua-5.1.5/test/factorial.lua @@ -0,0 +1,32 @@ +-- function closures are powerful + +-- traditional fixed-point operator from functional programming +Y = function (g) + local a = function (f) return f(f) end + return a(function (f) + return g(function (x) + local c=f(f) + return c(x) + end) + end) +end + + +-- factorial without recursion +F = function (f) + return function (n) + if n == 0 then return 1 + else return n*f(n-1) end + end + end + +factorial = Y(F) -- factorial is the fixed point of F + +-- now test it +function test(x) + io.write(x,"! = ",factorial(x),"\n") +end + +for n=0,16 do + test(n) +end |