Add Iterator.any?

This method can be used to check if an Iterator includes a certain
value.

This method does not reuse Iterator.find as the current Ruby compiler
does not know that type parameters are instances of Object, making it
impossible to use not_nil? on a ?T type.

runtime/src/std/iterator.inko

@@ -246,6 +246,26 @@ trait Iterator!(T) {
     Nil
   }
+  # Returns `True` if `self` contains any value for which the `block` argument
+  # returned `True`.
+  #
+  # This method stops iterating over the values after the first matching value.
+  #
+  # # Examples
+  #
+  # Checking if an `Iterator` contains a value:
+  #
+  #     Array.new(10, 20, 30).iter.any? do (value) { value >= 20 } # => True
+  def any?(block: do (T) -> Boolean) -> Boolean {
+    each do (value) {
+      block.call(value).if_true {
+        return True
+      }
+    }
+
+    False
+  }
+
   # Transforms the `Iterator` into an `Array`.
   #
   # This method will advance the iterator to the end.

runtime/tests/test/std/test_iterator.inko

@@ -94,6 +94,15 @@ test.group('std::iterator::Iterator.find') do (g) {
   }
 }
+test.group('std::iterator::Iterator.any?') do (g) {
+  g.test('Checking if an Iterator includes a value') {
+    let iter = SimpleIterator.new
+
+    assert.true(iter.any? do (value) { value == 20 })
+    assert.false(iter.any? do (value) { value == 200 })
+  }
+}
+
 test.group('std::iterator::Iterator.map') do (g) {
   g.test('Mapping the values of an Iterator to a different value') {
     let iter = SimpleIterator.new.map do (val) { val * 2 }