Merge #1232

1232: feat(interface-types) Implement the WAT decoder r=Hywan a=Hywan

WIP

The goal is the define a minimal WAT to AST decoder for WIT, so that it's muuuuuuch easier to develop and debug.

Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## **[Unreleased]**
 
+- [#1232](https://github.com/wasmerio/wasmer/pull/1232) `wasmer-interface-types` has a WAT decoder.
+
 ## 0.14.0 - 2020-02-20
 
 - [#1233](https://github.com/wasmerio/wasmer/pull/1233) Improved Wasmer C API release artifacts.

lib/interface-types/Cargo.toml

@@ -9,3 +9,4 @@ edition = "2018"
 
 [dependencies]
 nom = "5.1"
+wast = "8.0"

lib/interface-types/src/ast.rs

@@ -5,7 +5,7 @@ use crate::interpreter::Instruction;
 use std::str;
 
 /// Represents the types supported by WIT.
-#[derive(PartialEq, Clone, Debug)]
+#[derive(PartialEq, Debug)]
 pub enum InterfaceType {
     /// An integer.
     Int,
@@ -190,7 +190,7 @@ pub struct Forward<'input> {
 
 /// Represents a set of interfaces, i.e. it entirely describes a WIT
 /// definition.
-#[derive(PartialEq, Debug)]
+#[derive(PartialEq, Default, Debug)]
 pub struct Interfaces<'input> {
     /// All the exported functions.
     pub exports: Vec<Export<'input>>,

lib/interface-types/src/decoders/binary.rs

@@ -1,4 +1,4 @@
-//! Parse the WIT binary representation into an AST.
+//! Parse the WIT binary representation into an [AST](crate::ast).
 
 use crate::{ast::*, interpreter::Instruction};
 use nom::{
@@ -432,7 +432,8 @@ fn interfaces<'input, E: ParseError<&'input [u8]>>(
 }
 
 /// Parse a sequence of bytes, expecting it to be a valid WIT binary
-/// representation, into an `ast::Interfaces`.
+/// representation, into an [`Interfaces`](crate::ast::Interfaces)
+/// structure.
 ///
 /// # Example
 ///

lib/interface-types/src/decoders/mod.rs

@@ -1,4 +1,6 @@
 //! Reads the AST from a particular data representation; for instance,
-//! `decoders::binary` reads the AST from a binary.
+//! [`decoders::binary`](binary) reads the [AST](crate::ast)
+//! from a binary.
 
 pub mod binary;
+pub mod wat;