List.first, .classify

Author: moritz

lib/List.pod

@@ -32,10 +32,34 @@ the return values are accessed.
 =head2 grep
 
     multi sub    grep(Mu $matcher, *@elems) returns List:D
-    multi method grep(List:D:, Mu $matcher) returns List:D
+    multi method grep(List:D:  Mu $matcher) returns List:D
 
 Returns a lazy list of elements against which C<$matcher> smart-matches.
 The elements are returned in the order in which they appear in the original
 list.
 
+=head2 first
+
+    multi sub    first(Mu $matcher, *@elems)
+    multi method first(List:D:  Mu $matcher)
+
+Returns the first item of the list which smart-matches against C<$matcher>.
+
+=head2 classify
+
+    multi sub    classify(&mapper, *@values) returns Hash:D
+    multi method classify(List:D: &mapper)   returns Hash:D
+
+C<classify> transforms a list or array of values into a hash
+representing the classification of those values according to a mapper;
+each hash key represents the classification for one or more of the
+incoming list values, and the corresponding hash value contains
+an array of those list values classified by the mapper into the category
+of the associated key.  For example:
+
+  my @list = (1, 2, 3, 4);
+  my %h = classify { $_ % 2 ?? 'odd' !! 'even' }, @list;
+
+Creates the hash C<< { odd => [1, 3], even => [2, 4] } >> in C<%h>.
+
 =end pod