lib: add Array::+

[nit.git] / lib / standard / collection / array.nit

diff --git a/lib/standard/collection/array.nit b/lib/standard/collection/array.nit
index 61e8700..70e0b94 100644 (file)
--- a/lib/standard/collection/array.nit
+++ b/lib/standard/collection/array.nit
@@ -370,6 +370,30 @@ class Array[E]
                end
                return true
        end
+
+       # Concatenation of arrays.
+       #
+       # Returns a new array built by concatenating `self` and `other` together.
+       #
+       #     var a1 = [1,2,3]
+       #     var a2 = [4,5,6]
+       #     var a3 = a1 + a2
+       #     assert a3 == [1,2,3,4,5,6]
+       #
+       # Because a new array is always created, future modification on `self` and `other`
+       # does not impact the previously computed result.
+       #
+       #     a1.add(30)
+       #     a2.add(60)
+       #     assert a3      == [1,2,3,4,5,6] # unchanged
+       #     assert a1 + a2 == [1,2,3,30,4,5,6,60]
+       fun +(other: Array[E]): Array[E]
+       do
+               var res = new Array[E].with_capacity(length + other.length)
+               res.append(self)
+               res.append(other)
+               return res
+       end
 end
 
 # An `Iterator` on `AbstractArray`
@@ -416,7 +440,7 @@ class ArraySet[E: Object]
        super Set[E]
 
        # The stored elements.
-       private var array: Array[E]
+       private var array: Array[E] is noinit
 
        redef fun has(e) do return _array.has(e)