change indentation and finish naive_mul

polynome.ml

@@ -7,8 +7,9 @@ module type Coefficient =
     type coeff
     val print: coeff -> string
     val is_null: coeff -> bool
-    val add: coeff -> coeff -> coeff
     val equal: coeff -> coeff -> bool
+    val add: coeff -> coeff -> coeff
+    val mul: coeff -> coeff -> coeff
   end
 ;;
   
@@ -42,8 +43,7 @@ module Polynome (C : Coefficient) (D : Degree) =
       |NotNull (cc, dd, pp)->
 	      (C.print cc)^"X^"^(D.print dd)^"+"^(print pp)
     let rec equal x y = match x with
-      |Null ->
-	(match y with
+      |Null -> (match y with
 	      |Null -> true
 	      |NotNull (_, _, _)-> false)
       |NotNull (cx, dx, xx)->
@@ -55,7 +55,8 @@ module Polynome (C : Coefficient) (D : Degree) =
 	            if C.equal cx cy
 	            then equal xx yy
               else false
-           else false)
+            else false
+          )
     let rec add x y = match x with
       |Null -> y
       |NotNull (cx, dx, xx)->
@@ -73,17 +74,24 @@ module Polynome (C : Coefficient) (D : Degree) =
 	          then add xx yy
 	          else NotNull (m, dx, add xx yy)
 	      )
-    (*let rec naive_mul x y = match x with
+    (*private function for incrementing the degree of a polynome*)
+    let rec increment_degree d x = match x with 
+      |Null -> Null
+      |NotNull (cx, dx, xx)-> NotNull (cx, (D.add d dx), (increment_degree d xx))
+    (*private function in order to multiply all the coeffs of a pol*)
+    let rec multiply_coeffs c x = match x with 
       |Null -> Null
-      |NotNull -> (cx, dx, xx)->
+      |NotNull (cx, dx, xx) -> 
+          if C.is_null c then Null
+          else NotNull ((C.mul c cx), dx, (multiply_coeffs c xx))
+    (*Naive multiplication of two polynomes*)
+    let rec naive_mul x y = match x with
+      |Null -> Null
+      |NotNull (cx, dx, xx) ->
 	      (match y with
 	        |Null -> Null
-	 |NotNull (cy, dy, yy)->
-	   match xx with
-	   |Null
-	   |NotNull
+	        |NotNull (_, _, _)->
+            add (increment_degree dx (multiply_coeffs cx y))(naive_mul xx y)
 	      )
-     *)	  
-      
   end
 ;;