Added reduce function

main.roc

@@ -2,20 +2,42 @@ app [main] { pf: platform "https://github.com/roc-lang/basic-cli/releases/downlo
 
 import pf.Stdout
 
+# Functions to work with in the reduce function
+add = \a, b -> a + b
+mult = \a, b -> a * b
+
 
 # Recusivly incrementing counter until it hits maxLen
 # The plus one on the recursive call would be the current element of the list
 # Counter will be the current list index
-#sum : Num a, (List (Num a)) -> Num a where a implements Bool.Eq #Type Annotations are weird :(
+reduce : (List (Num a)), U64, Num a, (Num a, Num a -> Num a) -> Num a 
-sum = \counter, nums ->
+reduce = \nums, counter, neutral, func ->
+    if counter == (List.len nums) then
+        neutral
+    else
+        currentValue = listI nums counter
+        (func currentValue (reduce nums (counter + 1) neutral func))
+
+
+# Reduce with HeadAsTail      
+#reduce : (List(Num a)), Num a, (Num a, Num a -> Num a) -> Num a
+#reduce = \nums, neutral, func ->
+#    when nums is
+#        [] -> neutral
+#        [head, .. as tail] -> (func head (reduce tail neutral func))
+
+
+
+# Recusivly incrementing counter until it hits maxLen
+# The plus one on the recursive call would be the current element of the list
+# Counter will be the current list index
+sum : (List (Num a)), U64 -> Num a 
+sum = \nums, counter ->
     if counter == (List.len nums) then
         0
     else
         currentValue = listI nums counter
-        # Try to make type annotions work
+        ((sum nums (counter + 1)) + currentValue)
-        #newCounter: Num a where a implements Bool.Eq 
-        newCounter = counter + 1
-        ((sum newCounter nums) + currentValue)
 
 
 # Gets the value in a list at a given index
@@ -29,10 +51,28 @@ listI = \list, i ->
 
 
 main =
+    
     nums = [1, 20, 3, 1, 1]
-    #firstHun = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]
+    firstHun = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]
-    # Correct value for the first hundred list sum is 5050
+    firstTen = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
-    sumValue = sum 0 nums
+    
+    sumValue = sum nums 0
+    firstHunValue = sum firstHun 0
+    
+    reduceValue = reduce nums 0 0 add
+    reduceFirstHunValue = reduce firstHun 0 0 add
+
+    reduceMultNums = reduce nums 0 1 mult
+    reduceMultTen = reduce firstTen 0 1 mult
+
+
     dbg sumValue
+    dbg firstHunValue
+    
+    dbg reduceValue
+    dbg reduceFirstHunValue
+    
+    dbg reduceMultNums
+    dbg reduceMultTen
 
     Stdout.line! ("Finished!")