Merge pull request #432 from chriseth/alloc

Allocating arrays.

docs/types.rst

@@ -291,6 +291,27 @@ So `bytes` should always be preferred over `byte[]` because it is cheaper.
     that you are accessing the low-level bytes of the utf-8 representation,
     and not the individual characters!
 
+.. index:: ! array;allocating, new
+
+Allocating Memory Arrays
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+Creating arrays with variable length in memory can be done using the `new` keyword.
+As opposed to storage arrays, it is **not** possible to resize memory arrays by assigning to
+the `.length` member.
+
+::
+
+    contract C {
+      function f(uint len) {
+        uint[] memory a = new uint[](7);
+        bytes memory b = new bytes(len);
+        // Here we have a.length == 7 and b.length == len
+        a[6] = 8;
+      }
+    }
+
+
 .. index:: ! array;length, length, push, !array;push
 
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