feat(interface-types) Implement the record instructions

lib/interface-types/Cargo.toml

@@ -10,3 +10,11 @@ edition = "2018"
 [dependencies]
 nom = "5.1"
 wast = "8.0"
+
+# `serde` is useful only to simplify the users' life. It is not
+# required by WIT itself, is is used to transform WIT values like
+# `record`s to Rust sum types.
+serde = { version = "1.0", features = ["derive"], optional = true }
+
+[features]
+default = ["serde"]

lib/interface-types/src/ast.rs

@@ -48,20 +48,50 @@ pub enum InterfaceType {
 
     /// A 64-bits integer (as defiend in WebAssembly core).
     I64,
+
+    /// A record.
+    Record(RecordType),
+}
+
+/// Representing a record type.
+#[derive(PartialEq, Debug, Clone)]
+pub struct RecordType {
+    /// Types representing the fields.
+    pub fields: Vec<InterfaceType>,
 }
 
-/// Represents a type signature.
-///
-/// ```wasm,ignore
-/// (@interface type (param i32 i32) (result string))
-/// ```
+/// Represents the kind of type.
 #[derive(PartialEq, Debug)]
-pub struct Type {
-    /// Types for the parameters (`(param …)`).
-    pub inputs: Vec<InterfaceType>,
+pub enum TypeKind {
+    /// A function type.
+    Function,
 
-    /// Types for the results (`(result …)`).
-    pub outputs: Vec<InterfaceType>,
+    /// A record type.
+    Record,
+}
+
+/// Represents a type.
+#[derive(PartialEq, Debug)]
+pub enum Type {
+    /// A function type, like:
+    ///
+    /// ```wasm,ignore
+    /// (@interface type (func (param i32 i32) (result string)))
+    /// ```
+    Function {
+        /// Types for the parameters (`(param …)`).
+        inputs: Vec<InterfaceType>,
+
+        /// Types for the results (`(result …)`).
+        outputs: Vec<InterfaceType>,
+    },
+
+    /// A record type, like:
+    ///
+    /// ```wasm,ignore
+    /// (@interface type (record string i32))
+    /// ```
+    Record(RecordType),
 }
 
 /// Represents an imported function.