decl_storage as a proc_macro (#1176)

* `decl_storage` parsing of the macro (TODO change tool crate structure)

* Start formatting, for now use inner macro.
Still missing optional formating last part (genesis ...).

* Calling extra genesis macro

* decl_storage lines parsing.

* genesis macro as quote (need some cleaning reorg)

* dirty $crate substitute

* proc crate reorg.

* PR impl : skip usage of phantom data, it only applies in test and
council (others required it).

* Remaining macro of decl_storage, warning stringify behave sometime
oddly.

* Formatting code and some cleaning.

* Include line parsing to main struct (cannot use existing macro anymore).

* Remove genesis phantom data when there is already a field with type
parameter.

* Revert wasm files

* Remove old version of `decl_storage`.

* Fix false positive for phantom trait (additional type check on config
build).

* slight changes:
- return token errors instead of panic
- do not use useless intermediate vec

* Update srml/support/procedural/tools/derive/src/lib.rs

remove indent

Co-Authored-By: cheme <emericchevalier.pro@gmail.com>

* Switch iterations to fold, remove unused import.

substrate/srml/support/procedural/src/lib.rs

@@ -0,0 +1,59 @@
+// Copyright 2017-2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+// tag::description[]
+//! Proc macro of Support code for the runtime.
+// end::description[]
+
+#![recursion_limit="256"]
+
+extern crate proc_macro;
+extern crate proc_macro2;
+
+#[macro_use]
+extern crate syn;
+
+#[macro_use]
+extern crate quote;
+
+#[macro_use]
+extern crate srml_support_procedural_tools;
+
+mod storage;
+
+use proc_macro::TokenStream;
+
+/// Declares strongly-typed wrappers around codec-compatible types in storage.
+///
+/// ## Example
+///
+/// ```compile_fail
+/// decl_storage! {
+/// 	trait Store for Module<T: Trait> as Example {
+/// 		Dummy get(dummy) config(): Option<T::Balance>;
+/// 		Foo get(foo) config(): T::Balance;
+/// 	}
+/// }
+/// ```
+///
+/// For now we implement a convenience trait with pre-specialised associated types, one for each
+/// storage item. This allows you to gain access to publicly visible storage items from a
+/// module type. Currently you must disambiguate by using `<Module as Store>::Item` rather than
+/// the simpler `Module::Item`. Hopefully the rust guys with fix this soon.
+#[proc_macro]
+pub fn decl_storage(input: TokenStream) -> TokenStream {
+	storage::transformation::decl_storage_impl(input)
+}