webidl: initial enum support

Add enum support to the WebIDL interface generator.

crates/webidl/tests/all/enums.rs

@@ -0,0 +1,64 @@
+use super::project;
+
+#[test]
+fn top_level_enum() {
+    project()
+        .file(
+            "shape.webidl",
+            r#"
+            enum ShapeType { "circle", "square" };
+            
+            [Constructor(ShapeType kind)]
+            interface Shape {
+                [Pure]
+                boolean isSquare();
+
+                [Pure]
+                boolean isCircle();
+            };
+        "#,
+        )
+        .file(
+            "shape.mjs",
+            r#"
+            export class Shape {
+                constructor(kind) {
+                    this.kind = kind;
+                }
+
+                isSquare() {
+                    return this.kind === 'square';
+                }
+
+                isCircle() {
+                    return this.kind === 'circle';
+                }
+            }
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+            #![feature(proc_macro, wasm_custom_section, wasm_import_module)]
+
+            extern crate wasm_bindgen;
+
+            use wasm_bindgen::prelude::*;
+
+            pub mod shape;
+
+            use shape::{Shape, ShapeType};
+
+            #[wasm_bindgen]
+            pub fn test() {
+                let circle = Shape::new(ShapeType::Circle);
+                let square = Shape::new(ShapeType::Square);
+                assert!(circle.is_circle());
+                assert!(!circle.is_square());
+                assert!(square.is_square());
+                assert!(!square.is_circle());
+            }
+        "#,
+        )
+        .test();
+}

crates/webidl/tests/all/main.rs

@@ -2,3 +2,4 @@ extern crate wasm_bindgen_test_project_builder as project_builder;
 use project_builder::project;
 
 mod simple;
+mod enums;