Merge #1934

1934: Parse Path and AttrInput in Attr r=matklad a=uHOOCCOOHu

[Syntax reference](https://doc.rust-lang.org/reference/attributes.html#attributes)

Co-authored-by: uHOOCCOOHu <[email protected]>

4 files changed, 68 insertions, 53 deletions

diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index 8c5ece65d..cefc00402 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -1,10 +1,8 @@
 //! Various extension methods to ast Nodes, which are hard to code-generate.
 //! Extensions for various expressions live in a sibling `expr_extensions` module.
 
-use itertools::Itertools;
-
 use crate::{
-    ast::{self, child_opt, children, AstChildren, AstNode, SyntaxNode},
+    ast::{self, child_opt, children, AstChildren, AstNode, AttrInput, SyntaxNode},
     SmolStr, SyntaxElement,
     SyntaxKind::*,
     SyntaxToken, T,
@@ -38,62 +36,37 @@ fn text_of_first_token(node: &SyntaxNode) -> &SmolStr {
 }
 
 impl ast::Attr {
-    pub fn is_inner(&self) -> bool {
-        let tt = match self.value() {
-            None => return false,
-            Some(tt) => tt,
-        };
-
-        let prev = match tt.syntax().prev_sibling() {
-            None => return false,
-            Some(prev) => prev,
-        };
-
-        prev.kind() == T![!]
-    }
-
-    pub fn as_atom(&self) -> Option<SmolStr> {
-        let tt = self.value()?;
-        let (_bra, attr, _ket) = tt.syntax().children_with_tokens().collect_tuple()?;
-        if attr.kind() == IDENT {
-            Some(attr.as_token()?.text().clone())
-        } else {
-            None
+    pub fn as_simple_atom(&self) -> Option<SmolStr> {
+        match self.input() {
+            None => self.simple_name(),
+            Some(_) => None,
         }
     }
 
-    pub fn as_call(&self) -> Option<(SmolStr, ast::TokenTree)> {
-        let tt = self.value()?;
-        let (_bra, attr, args, _ket) = tt.syntax().children_with_tokens().collect_tuple()?;
-        let args = ast::TokenTree::cast(args.as_node()?.clone())?;
-        if attr.kind() == IDENT {
-            Some((attr.as_token()?.text().clone(), args))
-        } else {
-            None
+    pub fn as_simple_call(&self) -> Option<(SmolStr, ast::TokenTree)> {
+        match self.input() {
+            Some(AttrInput::TokenTree(tt)) => Some((self.simple_name()?, tt)),
+            _ => None,
         }
     }
 
-    pub fn as_named(&self) -> Option<SmolStr> {
-        let tt = self.value()?;
-        let attr = tt.syntax().children_with_tokens().nth(1)?;
-        if attr.kind() == IDENT {
-            Some(attr.as_token()?.text().clone())
-        } else {
-            None
+    pub fn as_simple_key_value(&self) -> Option<(SmolStr, SmolStr)> {
+        match self.input() {
+            Some(AttrInput::Literal(lit)) => {
+                let key = self.simple_name()?;
+                // FIXME: escape? raw string?
+                let value = lit.syntax().first_token()?.text().trim_matches('"').into();
+                Some((key, value))
+            }
+            _ => None,
         }
     }
 
-    pub fn as_key_value(&self) -> Option<(SmolStr, SmolStr)> {
-        let tt = self.value()?;
-        let tt_node = tt.syntax();
-        let attr = tt_node.children_with_tokens().nth(1)?;
-        if attr.kind() == IDENT {
-            let key = attr.as_token()?.text().clone();
-            let val_node = tt_node.children_with_tokens().find(|t| t.kind() == STRING)?;
-            let val = val_node.as_token()?.text().trim_start_matches('"').trim_end_matches('"');
-            Some((key, SmolStr::new(val)))
-        } else {
-            None
+    pub fn simple_name(&self) -> Option<SmolStr> {
+        let path = self.path()?;
+        match (path.segment(), path.qualifier()) {
+            (Some(segment), None) => Some(segment.syntax().first_token()?.text().clone()),
+            _ => None,
         }
     }
 }
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index dc1f8c82c..aaf03ce3f 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -166,11 +166,52 @@ impl AstNode for Attr {
     }
 }
 impl Attr {
-    pub fn value(&self) -> Option<TokenTree> {
+    pub fn path(&self) -> Option<Path> {
+        AstChildren::new(&self.syntax).next()
+    }
+    pub fn input(&self) -> Option<AttrInput> {
         AstChildren::new(&self.syntax).next()
     }
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum AttrInput {
+    Literal(Literal),
+    TokenTree(TokenTree),
+}
+impl From<Literal> for AttrInput {
+    fn from(node: Literal) -> AttrInput {
+        AttrInput::Literal(node)
+    }
+}
+impl From<TokenTree> for AttrInput {
+    fn from(node: TokenTree) -> AttrInput {
+        AttrInput::TokenTree(node)
+    }
+}
+impl AstNode for AttrInput {
+    fn can_cast(kind: SyntaxKind) -> bool {
+        match kind {
+            LITERAL | TOKEN_TREE => true,
+            _ => false,
+        }
+    }
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        let res = match syntax.kind() {
+            LITERAL => AttrInput::Literal(Literal { syntax }),
+            TOKEN_TREE => AttrInput::TokenTree(TokenTree { syntax }),
+            _ => return None,
+        };
+        Some(res)
+    }
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            AttrInput::Literal(it) => &it.syntax,
+            AttrInput::TokenTree(it) => &it.syntax,
+        }
+    }
+}
+impl AttrInput {}
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct AwaitExpr {
     pub(crate) syntax: SyntaxNode,
 }
diff --git a/crates/ra_syntax/src/ast/traits.rs b/crates/ra_syntax/src/ast/traits.rs
index c3e676d4c..f275a4955 100644
--- a/crates/ra_syntax/src/ast/traits.rs
+++ b/crates/ra_syntax/src/ast/traits.rs
@@ -99,7 +99,7 @@ pub trait AttrsOwner: AstNode {
         children(self)
     }
     fn has_atom_attr(&self, atom: &str) -> bool {
-        self.attrs().filter_map(|x| x.as_atom()).any(|x| x == atom)
+        self.attrs().filter_map(|x| x.as_simple_atom()).any(|x| x == atom)
     }
 }
 
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 5f395501a..30328f59f 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -576,7 +576,8 @@ Grammar(
             traits: [ "NameOwner", "AttrsOwner","DocCommentsOwner" ],
             options: [ "TokenTree", "Path" ],
         ),
-        "Attr": ( options: [ ["value", "TokenTree"] ] ),
+        "AttrInput": ( enum: [ "Literal", "TokenTree" ] ),
+        "Attr": ( options: [ "Path", [ "input", "AttrInput" ] ] ),
         "TokenTree": (),
         "TypeParamList": (
             collections: [