#181 - introduced list.eachi

src/main/eo/org/eolang/collections/list.eo

@@ -59,6 +59,13 @@
           arr.length
           i
 
+  # @todo #181:30min Wrong order of the attributes of object "f". For some
+  #  reason "reducedi" is the only object that walks through array and where
+  #  function has attributes in next order: accumulator, index, item. All
+  #  other objects like mappedi, filteredi, eachi have attributes in the next
+  #  order: item, index. So "index" must be after "item" object. Also need to
+  #  change the order of attributes in all other objects that use "reducedi"
+  #
   # Reduce with index from start "a" using the function "f".
   # Here "f" must be an abstract
   # object with three free attributes. The first
@@ -123,16 +130,28 @@
 
   # For each array element dataize the object
   # Here "f" must be an abstract object with
-  # one free attribute, the element of the
-  # array.
-  [f] > each
+  # two free attributes: the element of the
+  # array and its index.
+  [f] > eachi
     seq > @
-      ^.reduced
+      ^.reducedi
         TRUE
-        [a x]
-          f x > @
+        [a i x]
+          &.f > @
+            x
+            i
       TRUE
 
+  # For each array element dataize the object
+  # Here "f" must be an abstract object with
+  # one free attribute, the element of the
+  # array.
+  [f] > each
+    ^.eachi > @
+      [x i]
+        &.f > @
+          x
+
   # Create a new list without the i-th element
   [i] > withouti
     ^.reducedi > @

src/test/eo/org/eolang/collections/list-tests.eo

@@ -277,6 +277,20 @@
   .each > @
     [i] (stdout i > @)
 
+[] > iterates-with-eachi
+  list
+    *
+      "one"
+      "two"
+      "three"
+  .eachi > @
+    [item index]
+      stdout > @
+        sprintf
+          "[%d]: %s\n"
+          index
+          item
+
 [] > list-withouti
   assert-that > @
     withouti.