Merge pull request #618 from chriseth/inlineArrays

Document inline arrays.

1 files changed, 38 insertions, 0 deletions

diff --git a/docs/types.rst b/docs/types.rst
index 6a69f5be..9de83843 100644
--- a/docs/types.rst
+++ b/docs/types.rst
@@ -364,6 +364,44 @@ the ``.length`` member.
         }
     }
 
+.. index:: ! array;literals, !inline;arrays
+
+Array Literals / Inline Arrays
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Array literals are arrays that are written as an expression and are not
+assigned to a variable right away.
+
+::
+
+    contract C {
+        function f() {
+            g([uint(1), 2, 3]);
+        }
+        function g(uint[3] _data) {
+            // ...
+        }
+    }
+
+The type of an array literal is a memory array of fixed size whose base
+type is the common type of the given elements. The type of ``[1, 2, 3]`` is
+``uint8[3] memory``, because the type of each of these constants is ``uint8``.
+Because of that, it was necessary to convert the first element in the example
+above to ``uint``. Note that currently, fixed size memory arrays cannot
+be assigned to dynamically-sized memory arrays, i.e. the following is not
+possible:
+
+::
+
+    contract C {
+        function f() {
+            // The next line creates a type error because uint[3] memory
+            // cannot be converted to uint[] memory.
+            uint[] x = [uint(1), 3, 4];
+    }
+
+It is planned to remove this restriction in the future but currently creates
+some complications because of how arrays are passed in the ABI.
 
 .. index:: ! array;length, length, push, !array;push