1 files changed, 303 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
new file mode 100644
index 000000000..aec57c380
--- /dev/null
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -0,0 +1,303 @@
+//! 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::{
+    SmolStr, SyntaxToken,
+    ast::{self, AstNode, children, child_opt},
+    SyntaxKind::*,
+};
+
+impl ast::Name {
+    pub fn text(&self) -> &SmolStr {
+        let ident = self.syntax().first_child_or_token().unwrap().as_token().unwrap();
+        ident.text()
+    }
+}
+
+impl ast::NameRef {
+    pub fn text(&self) -> &SmolStr {
+        let ident = self.syntax().first_child_or_token().unwrap().as_token().unwrap();
+        ident.text()
+    }
+}
+
+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() == EXCL
+    }
+
+    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_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()?)?;
+        if attr.kind() == IDENT {
+            Some((attr.as_token()?.text().clone(), args))
+        } else {
+            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
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PathSegmentKind<'a> {
+    Name(&'a ast::NameRef),
+    SelfKw,
+    SuperKw,
+    CrateKw,
+}
+
+impl ast::PathSegment {
+    pub fn parent_path(&self) -> &ast::Path {
+        self.syntax()
+            .parent()
+            .and_then(ast::Path::cast)
+            .expect("segments are always nested in paths")
+    }
+
+    pub fn kind(&self) -> Option<PathSegmentKind> {
+        let res = if let Some(name_ref) = self.name_ref() {
+            PathSegmentKind::Name(name_ref)
+        } else {
+            match self.syntax().first_child_or_token()?.kind() {
+                SELF_KW => PathSegmentKind::SelfKw,
+                SUPER_KW => PathSegmentKind::SuperKw,
+                CRATE_KW => PathSegmentKind::CrateKw,
+                _ => return None,
+            }
+        };
+        Some(res)
+    }
+
+    pub fn has_colon_colon(&self) -> bool {
+        match self.syntax.first_child_or_token().map(|s| s.kind()) {
+            Some(COLONCOLON) => true,
+            _ => false,
+        }
+    }
+}
+
+impl ast::Path {
+    pub fn parent_path(&self) -> Option<&ast::Path> {
+        self.syntax().parent().and_then(ast::Path::cast)
+    }
+}
+
+impl ast::Module {
+    pub fn has_semi(&self) -> bool {
+        match self.syntax().last_child_or_token() {
+            None => false,
+            Some(node) => node.kind() == SEMI,
+        }
+    }
+}
+
+impl ast::UseTree {
+    pub fn has_star(&self) -> bool {
+        self.syntax().children_with_tokens().any(|it| it.kind() == STAR)
+    }
+}
+
+impl ast::UseTreeList {
+    pub fn parent_use_tree(&self) -> &ast::UseTree {
+        self.syntax()
+            .parent()
+            .and_then(ast::UseTree::cast)
+            .expect("UseTreeLists are always nested in UseTrees")
+    }
+}
+
+impl ast::ImplBlock {
+    pub fn target_type(&self) -> Option<&ast::TypeRef> {
+        match self.target() {
+            (Some(t), None) | (_, Some(t)) => Some(t),
+            _ => None,
+        }
+    }
+
+    pub fn target_trait(&self) -> Option<&ast::TypeRef> {
+        match self.target() {
+            (Some(t), Some(_)) => Some(t),
+            _ => None,
+        }
+    }
+
+    fn target(&self) -> (Option<&ast::TypeRef>, Option<&ast::TypeRef>) {
+        let mut types = children(self);
+        let first = types.next();
+        let second = types.next();
+        (first, second)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum StructKind<'a> {
+    Tuple(&'a ast::PosFieldDefList),
+    Named(&'a ast::NamedFieldDefList),
+    Unit,
+}
+
+impl StructKind<'_> {
+    fn from_node<N: AstNode>(node: &N) -> StructKind {
+        if let Some(nfdl) = child_opt::<_, ast::NamedFieldDefList>(node) {
+            StructKind::Named(nfdl)
+        } else if let Some(pfl) = child_opt::<_, ast::PosFieldDefList>(node) {
+            StructKind::Tuple(pfl)
+        } else {
+            StructKind::Unit
+        }
+    }
+}
+
+impl ast::StructDef {
+    pub fn kind(&self) -> StructKind {
+        StructKind::from_node(self)
+    }
+}
+
+impl ast::EnumVariant {
+    pub fn parent_enum(&self) -> &ast::EnumDef {
+        self.syntax()
+            .parent()
+            .and_then(|it| it.parent())
+            .and_then(ast::EnumDef::cast)
+            .expect("EnumVariants are always nested in Enums")
+    }
+    pub fn kind(&self) -> StructKind {
+        StructKind::from_node(self)
+    }
+}
+
+impl ast::LetStmt {
+    pub fn has_semi(&self) -> bool {
+        match self.syntax().last_child_or_token() {
+            None => false,
+            Some(node) => node.kind() == SEMI,
+        }
+    }
+}
+
+impl ast::ExprStmt {
+    pub fn has_semi(&self) -> bool {
+        match self.syntax().last_child_or_token() {
+            None => false,
+            Some(node) => node.kind() == SEMI,
+        }
+    }
+}
+
+impl ast::RefPat {
+    pub fn is_mut(&self) -> bool {
+        self.syntax().children_with_tokens().any(|n| n.kind() == MUT_KW)
+    }
+}
+
+impl ast::BindPat {
+    pub fn is_mutable(&self) -> bool {
+        self.syntax().children_with_tokens().any(|n| n.kind() == MUT_KW)
+    }
+
+    pub fn is_ref(&self) -> bool {
+        self.syntax().children_with_tokens().any(|n| n.kind() == REF_KW)
+    }
+}
+
+impl ast::PointerType {
+    pub fn is_mut(&self) -> bool {
+        self.syntax().children_with_tokens().any(|n| n.kind() == MUT_KW)
+    }
+}
+
+impl ast::ReferenceType {
+    pub fn is_mut(&self) -> bool {
+        self.syntax().children_with_tokens().any(|n| n.kind() == MUT_KW)
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum SelfParamKind {
+    /// self
+    Owned,
+    /// &self
+    Ref,
+    /// &mut self
+    MutRef,
+}
+
+impl ast::SelfParam {
+    pub fn self_kw_token(&self) -> SyntaxToken {
+        self.syntax()
+            .children_with_tokens()
+            .filter_map(|it| it.as_token())
+            .find(|it| it.kind() == SELF_KW)
+            .expect("invalid tree: self param must have self")
+    }
+
+    pub fn kind(&self) -> SelfParamKind {
+        let borrowed = self.syntax().children_with_tokens().any(|n| n.kind() == AMP);
+        if borrowed {
+            // check for a `mut` coming after the & -- `mut &self` != `&mut self`
+            if self
+                .syntax()
+                .children_with_tokens()
+                .skip_while(|n| n.kind() != AMP)
+                .any(|n| n.kind() == MUT_KW)
+            {
+                SelfParamKind::MutRef
+            } else {
+                SelfParamKind::Ref
+            }
+        } else {
+            SelfParamKind::Owned
+        }
+    }
+}
+
+impl ast::LifetimeParam {
+    pub fn lifetime_token(&self) -> Option<SyntaxToken> {
+        self.syntax()
+            .children_with_tokens()
+            .filter_map(|it| it.as_token())
+            .find(|it| it.kind() == LIFETIME)
+    }
+}
+
+impl ast::WherePred {
+    pub fn lifetime_token(&self) -> Option<SyntaxToken> {
+        self.syntax()
+            .children_with_tokens()
+            .filter_map(|it| it.as_token())
+            .find(|it| it.kind() == LIFETIME)
+    }
+}