separated into modules, added parser and lexer for miniImp

lib/utility/dune

@@ -0,0 +1,5 @@
+(library
+ (name utility)
+ (public_name utility))
+
+(include_subdirs qualified)

lib/utility/utility.ml

@@ -0,0 +1,13 @@
+let rec pow a = function
+  | 0 -> 1
+  | 1 -> a
+  | n ->
+    let b = pow a (n / 2) in
+    b * b * (if n mod 2 = 0 then 1 else a)
+
+let rec powmod a d = function
+  | 0 -> 1
+  | 1 -> a mod d
+  | n ->
+    let b = (powmod a d (n / 2)) mod d in
+    (((b * b) mod d) * (if n mod 2 = 0 then 1 else a)) mod d

lib/utility/utility.mli

@@ -0,0 +1,3 @@
+val pow : int -> int -> int
+
+val powmod : int -> int -> int -> int