add docs

src/lib.rs

@@ -14,11 +14,47 @@
  * limitations under the License.
  */
 
-//! Rust backend SDK for applications on the Fluence network. This crate is just a wrapper for two
-//! other crates: `main` and `macro`. The `main` crate is used for all memory relative operations
-//! and logging, while the `macro` crate contains the invocation macro to simplify entry point
-//! functions.
+//! Rust backend SDK for applications on the Fluence network. This crate defines the procedure macro
+//! `#[fce]` that could be applied to a function, structure or extern block.
 //!
+//! Structures with `#[fce]` could be used then in function arguments and values
+//! (hereinafter they'll be called records). All fields of a record should be public and have one of the
+//! following primitive Rust types
+//! (`bool, u8, u16, u32, u64, i8, i16, i32, i64, f32, f64, String, Vec<u8>`).
+//! ```rust
+//! use fluence::fce;
+//!
+//! #[fce]
+//! struct T {
+//!     field_1: i32,
+//!     field_2: Vec<u8>,
+//! }
+//! ```
+//!
+//! Functions with `#[fce]` will be exported from this module:
+//!
+//! ```rust
+//! use fluence::fce;
+//!
+//! #[fce]
+//! pub fn get(url: String) -> String {
+//!    // ...
+//! }
+//! ```
+//! At now, such functions could have arguments with primitive Rust types and record and only one
+//! return argument with such type could be used.
+//!
+//! Finally, to import other wasm modules to your project use similar code:
+//! ```rust
+//! use fluence::fce;
+//!
+//! #[fce]
+//! #[link(wasm_import_module = "wasm_curl.wasm")]
+//! extern "C" {
+//!     #[link_name = "get"]
+//!     pub fn curl_get(url: String) -> String;
+//! }
+//! ```
 #![doc(html_root_url = "https://docs.rs/fluence/0.2.0")]
 #![deny(
     dead_code,