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| -rw-r--r-- | docs/abi-spec.rst | 92 |
1 files changed, 89 insertions, 3 deletions
diff --git a/docs/abi-spec.rst b/docs/abi-spec.rst index f75a6885..6df9f1d5 100644 --- a/docs/abi-spec.rst +++ b/docs/abi-spec.rst @@ -289,14 +289,16 @@ In effect, a log entry using this ABI is described as: JSON ==== -The JSON format for a contract's interface is given by an array of function and/or event descriptions. A function description is a JSON object with the fields: +The JSON format for a contract's interface is given by an array of function and/or event descriptions. +A function description is a JSON object with the fields: - ``type``: ``"function"``, ``"constructor"``, or ``"fallback"`` (the :ref:`unnamed "default" function <fallback-function>`); - ``name``: the name of the function; - ``inputs``: an array of objects, each of which contains: * ``name``: the name of the parameter; - * ``type``: the canonical type of the parameter. + * ``type``: the canonical type of the parameter (more below). + * ``components``: used for tuple types (more below). - ``outputs``: an array of objects similar to ``inputs``, can be omitted if function doesn't return anything; - ``payable``: ``true`` if function accepts ether, defaults to ``false``; @@ -316,7 +318,8 @@ An event description is a JSON object with fairly similar fields: - ``inputs``: an array of objects, each of which contains: * ``name``: the name of the parameter; - * ``type``: the canonical type of the parameter. + * ``type``: the canonical type of the parameter (more below). + * ``components``: used for tuple types (more below). * ``indexed``: ``true`` if the field is part of the log's topics, ``false`` if it one of the log's data segment. - ``anonymous``: ``true`` if the event was declared as ``anonymous``. @@ -353,3 +356,86 @@ would result in the JSON: "name":"foo", "outputs": [] }] + +Use of Structs in Types +----------------------- + +If structs are part of the type, we still want to know the name of the components. Because of that, +the json structure gets arbitrarily nested in the following way: + +An object with members ``name``, ``type`` and potentially ``components`` describes a typed variable. +The canonical type is determined until a struct type is reached and the string description up +to that point is stored in ``type``, i.e. it will be a sequence of ``[]`` and ``[k]`` with +integers ``k``. The components of the struct are then stored in the member ``components``, +which is of array type and has the same structure as the top-level object except that +``indexed`` is not allowed there. + +As an example, the code + +:: + + contract Test { + struct S { uint a; uint[] b; T[] c; } + struct T { uint x; uint y; } + function f(S s, T t, uint a) { } + } + +would result in the JSON: + +.. code:: json + + [ + { + "name": "f", + "type": "function", + "inputs": [ + { + "name": "s", + "type": "", + "components": [ + { + "name": "a", + "type": "uint256" + }, + { + "name": "b", + "type": "uint256[]" + }, + { + "name": "c", + "type": "[]", + "components": [ + { + "name": "x", + "type": "uint256" + }, + { + "name": "y", + "type": "uint256" + } + ] + } + ] + }, + { + "name": "t", + "type": "", + "components": [ + { + "name": "x", + "type": "uint256" + }, + { + "name": "y", + "type": "uint256" + } + ] + }, + { + "name": "a", + "type": "uint256" + } + ], + "outputs": [] + } + ] |