feat: add struct parsing support for human readable ABI (#226)

* refactor: extract error module and use error macros

* feat: add solidity struct parser

* refactor: add AbiParse and support struct parsing

* test: add more struct parsing tests

ethers-core/src/abi/error.rs

@@ -0,0 +1,25 @@
+//! Boilerplate error definitions.
+use thiserror::Error;
+
+/// A type alias for std's Result with the Error as our error type.
+pub type Result<T, E = ParseError> = std::result::Result<T, E>;
+
+#[derive(Error, Debug)]
+pub enum ParseError {
+    #[error("{0}")]
+    Message(String),
+    #[error(transparent)]
+    ParseError(#[from] super::Error),
+}
+
+macro_rules! _format_err {
+    ($($tt:tt)*) => {
+        $crate::abi::ParseError::Message(format!($($tt)*))
+    };
+}
+pub(crate) use _format_err as format_err;
+
+macro_rules! _bail {
+    ($($tt:tt)*) => { return Err($crate::abi::error::format_err!($($tt)*)) };
+}
+pub(crate) use _bail as bail;