1 files changed, 79 insertions, 0 deletions

diff --git a/src/grammar/attributes.rs b/src/grammar/attributes.rs
new file mode 100644
index 000000000..c411d4d7f
--- /dev/null
+++ b/src/grammar/attributes.rs
@@ -0,0 +1,79 @@
+use super::*;
+
+pub(super) fn inner_attributes(p: &mut Parser) {
+    while p.current() == POUND && p.nth(1) == EXCL {
+        attribute(p, true)
+    }
+}
+
+pub(super) fn outer_attributes(p: &mut Parser) {
+    while p.at(POUND) {
+        attribute(p, false)
+    }
+}
+
+fn attribute(p: &mut Parser, inner: bool) {
+    let attr = p.start();
+    assert!(p.at(POUND));
+    p.bump();
+
+    if inner {
+        assert!(p.at(EXCL));
+        p.bump();
+    }
+
+    if p.expect(L_BRACK) {
+        meta_item(p);
+        p.expect(R_BRACK);
+    }
+    attr.complete(p, ATTR);
+}
+
+fn meta_item(p: &mut Parser) {
+    if p.at(IDENT) {
+        let meta_item = p.start();
+        p.bump();
+        match p.current() {
+            EQ => {
+                p.bump();
+                if expressions::literal(p).is_none() {
+                    p.error("expected literal");
+                }
+            }
+            L_PAREN => meta_item_arg_list(p),
+            _ => (),
+        }
+        meta_item.complete(p, META_ITEM);
+    } else {
+        p.error("expected attribute value");
+    }
+}
+
+fn meta_item_arg_list(p: &mut Parser) {
+    assert!(p.at(L_PAREN));
+    p.bump();
+    loop {
+        match p.current() {
+            EOF | R_PAREN => break,
+            IDENT => meta_item(p),
+            c => if expressions::literal(p).is_none() {
+                let message = "expected attribute";
+
+                if items::ITEM_FIRST.contains(c) {
+                    p.error(message);
+                    return;
+                }
+
+                let err = p.start();
+                p.error(message);
+                p.bump();
+                err.complete(p, ERROR);
+                continue;
+            },
+        }
+        if !p.at(R_PAREN) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(R_PAREN);
+}