1 files changed, 141 insertions, 0 deletions
diff --git a/third_party/rust/wast/src/component/export.rs b/third_party/rust/wast/src/component/export.rs
new file mode 100644
index 0000000000..a3b2bd7c0e
--- /dev/null
+++ b/third_party/rust/wast/src/component/export.rs
@@ -0,0 +1,141 @@
+use super::ItemRef;
+use crate::kw;
+use crate::parser::{Cursor, Parse, Parser, Peek, Result};
+use crate::token::{Id, Index, Span};
+
+/// An entry in a WebAssembly component's export section.
+#[derive(Debug)]
+pub struct ComponentExport<'a> {
+    /// Where this export was defined.
+    pub span: Span,
+    /// The name of this export from the component.
+    pub name: &'a str,
+    /// The kind of export.
+    pub kind: ComponentExportKind<'a>,
+}
+
+impl<'a> Parse<'a> for ComponentExport<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::export>()?.0;
+        let name = parser.parse()?;
+        let kind = parser.parse()?;
+        Ok(ComponentExport { span, name, kind })
+    }
+}
+
+impl<'a> Parse<'a> for Vec<ComponentExport<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut exports = Vec::new();
+        while !parser.is_empty() {
+            exports.push(parser.parens(|parser| parser.parse())?);
+        }
+        Ok(exports)
+    }
+}
+
+/// The kind of exported item.
+#[derive(Debug)]
+pub enum ComponentExportKind<'a> {
+    /// The export is a core module.
+    ///
+    /// Note this isn't a core item ref as currently only
+    /// components can export core modules.
+    CoreModule(ItemRef<'a, kw::module>),
+    /// The export is a function.
+    Func(ItemRef<'a, kw::func>),
+    /// The export is a value.
+    Value(ItemRef<'a, kw::value>),
+    /// The export is a type.
+    Type(ItemRef<'a, kw::r#type>),
+    /// The export is a component.
+    Component(ItemRef<'a, kw::component>),
+    /// The export is an instance.
+    Instance(ItemRef<'a, kw::instance>),
+}
+
+impl<'a> ComponentExportKind<'a> {
+    pub(crate) fn module(span: Span, id: Id<'a>) -> Self {
+        Self::CoreModule(ItemRef {
+            kind: kw::module(span),
+            idx: Index::Id(id),
+            export_names: Default::default(),
+        })
+    }
+
+    pub(crate) fn component(span: Span, id: Id<'a>) -> Self {
+        Self::Component(ItemRef {
+            kind: kw::component(span),
+            idx: Index::Id(id),
+            export_names: Default::default(),
+        })
+    }
+
+    pub(crate) fn instance(span: Span, id: Id<'a>) -> Self {
+        Self::Instance(ItemRef {
+            kind: kw::instance(span),
+            idx: Index::Id(id),
+            export_names: Default::default(),
+        })
+    }
+
+    pub(crate) fn func(span: Span, id: Id<'a>) -> Self {
+        Self::Func(ItemRef {
+            kind: kw::func(span),
+            idx: Index::Id(id),
+            export_names: Default::default(),
+        })
+    }
+}
+
+impl<'a> Parse<'a> for ComponentExportKind<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parens(|parser| {
+            let mut l = parser.lookahead1();
+            if l.peek::<kw::core>() {
+                // Remove core prefix
+                parser.parse::<kw::core>()?;
+                Ok(Self::CoreModule(parser.parse()?))
+            } else if l.peek::<kw::func>() {
+                Ok(Self::Func(parser.parse()?))
+            } else if l.peek::<kw::value>() {
+                Ok(Self::Value(parser.parse()?))
+            } else if l.peek::<kw::r#type>() {
+                Ok(Self::Type(parser.parse()?))
+            } else if l.peek::<kw::component>() {
+                Ok(Self::Component(parser.parse()?))
+            } else if l.peek::<kw::instance>() {
+                Ok(Self::Instance(parser.parse()?))
+            } else {
+                Err(l.error())
+            }
+        })
+    }
+}
+
+impl Peek for ComponentExportKind<'_> {
+    fn peek(cursor: Cursor) -> bool {
+        let cursor = match cursor.lparen() {
+            Some(c) => c,
+            None => return false,
+        };
+
+        let cursor = match cursor.keyword() {
+            Some(("core", c)) => match c.keyword() {
+                Some(("module", c)) => c,
+                _ => return false,
+            },
+            Some(("func", c))
+            | Some(("value", c))
+            | Some(("type", c))
+            | Some(("component", c))
+            | Some(("instance", c)) => c,
+            _ => return false,
+        };
+
+        Index::peek(cursor)
+    }
+
+    fn display() -> &'static str {
+        "component export"
+    }
+}