feat(interface-types) Implement the WAT decoder

lib/interface-types/Cargo.toml

@@ -8,4 +8,5 @@ repository = "https://github.com/wasmerio/wasmer"
 edition = "2018"
 
 [dependencies]
-nom = "5.1"
+nom = "5.1"
+wast = "8.0"

lib/interface-types/src/ast.rs

@@ -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/mod.rs

@@ -2,3 +2,4 @@
 //! `decoders::binary` reads the AST from a binary.
 
 pub mod binary;
+pub mod wat;