1 files changed, 206 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/ast/mod.rs b/crates/ra_syntax/src/ast/mod.rs
new file mode 100644
index 000000000..a6da82957
--- /dev/null
+++ b/crates/ra_syntax/src/ast/mod.rs
@@ -0,0 +1,206 @@
+mod generated;
+
+use std::marker::PhantomData;
+
+use itertools::Itertools;
+use smol_str::SmolStr;
+
+use {
+    SyntaxNodeRef, SyntaxKind::*,
+    yellow::{RefRoot, SyntaxNodeChildren},
+};
+pub use self::generated::*;
+
+pub trait AstNode<'a>: Clone + Copy + 'a {
+    fn cast(syntax: SyntaxNodeRef<'a>) -> Option<Self>
+        where Self: Sized;
+    fn syntax(self) -> SyntaxNodeRef<'a>;
+}
+
+pub trait NameOwner<'a>: AstNode<'a> {
+    fn name(self) -> Option<Name<'a>> {
+        child_opt(self)
+    }
+}
+
+pub trait LoopBodyOwner<'a>: AstNode<'a> {
+    fn loop_body(self) -> Option<Block<'a>> {
+        child_opt(self)
+    }
+}
+
+pub trait ArgListOwner<'a>: AstNode<'a> {
+    fn arg_list(self) -> Option<ArgList<'a>> {
+        child_opt(self)
+    }
+}
+
+pub trait FnDefOwner<'a>: AstNode<'a> {
+    fn functions(self) -> AstChildren<'a, FnDef<'a>> {
+        children(self)
+    }
+}
+
+pub trait ModuleItemOwner<'a>: AstNode<'a> {
+    fn items(self) -> AstChildren<'a, ModuleItem<'a>> {
+        children(self)
+    }
+}
+
+pub trait TypeParamsOwner<'a>: AstNode<'a> {
+    fn type_param_list(self) -> Option<TypeParamList<'a>> {
+        child_opt(self)
+    }
+
+    fn where_clause(self) -> Option<WhereClause<'a>> {
+        child_opt(self)
+    }
+}
+
+pub trait AttrsOwner<'a>: AstNode<'a> {
+    fn attrs(self) -> AstChildren<'a, Attr<'a>> {
+        children(self)
+    }
+}
+
+impl<'a> FnDef<'a> {
+    pub fn has_atom_attr(&self, atom: &str) -> bool {
+        self.attrs()
+            .filter_map(|x| x.as_atom())
+            .any(|x| x == atom)
+    }
+}
+
+impl<'a> Attr<'a> {
+    pub fn as_atom(&self) -> Option<SmolStr> {
+        let tt = self.value()?;
+        let (_bra, attr, _ket) = tt.syntax().children().collect_tuple()?;
+        if attr.kind() == IDENT {
+            Some(attr.leaf_text().unwrap())
+        } else {
+            None
+        }
+    }
+
+    pub fn as_call(&self) -> Option<(SmolStr, TokenTree<'a>)> {
+        let tt = self.value()?;
+        let (_bra, attr, args, _ket) = tt.syntax().children().collect_tuple()?;
+        let args = TokenTree::cast(args)?;
+        if attr.kind() == IDENT {
+            Some((attr.leaf_text().unwrap(), args))
+        } else {
+            None
+        }
+    }
+}
+
+impl<'a> Lifetime<'a> {
+    pub fn text(&self) -> SmolStr {
+        self.syntax().leaf_text().unwrap()
+    }
+}
+
+impl<'a> Name<'a> {
+    pub fn text(&self) -> SmolStr {
+        let ident = self.syntax().first_child()
+            .unwrap();
+        ident.leaf_text().unwrap()
+    }
+}
+
+impl<'a> NameRef<'a> {
+    pub fn text(&self) -> SmolStr {
+        let ident = self.syntax().first_child()
+            .unwrap();
+        ident.leaf_text().unwrap()
+    }
+}
+
+impl<'a> ImplItem<'a> {
+    pub fn target_type(self) -> Option<TypeRef<'a>> {
+        match self.target() {
+            (Some(t), None) | (_, Some(t)) => Some(t),
+            _ => None,
+        }
+    }
+
+    pub fn target_trait(self) -> Option<TypeRef<'a>> {
+        match self.target() {
+            (Some(t), Some(_)) => Some(t),
+            _ => None,
+        }
+    }
+
+    fn target(self) -> (Option<TypeRef<'a>>, Option<TypeRef<'a>>) {
+        let mut types = children(self);
+        let first = types.next();
+        let second = types.next();
+        (first, second)
+    }
+}
+
+impl<'a> Module<'a> {
+    pub fn has_semi(self) -> bool {
+        match self.syntax().last_child() {
+            None => false,
+            Some(node) => node.kind() == SEMI,
+        }
+    }
+}
+
+impl<'a> LetStmt<'a> {
+    pub fn has_semi(self) -> bool {
+        match self.syntax().last_child() {
+            None => false,
+            Some(node) => node.kind() == SEMI,
+        }
+    }
+}
+
+impl<'a> IfExpr<'a> {
+    pub fn then_branch(self) -> Option<Block<'a>> {
+        self.blocks().nth(0)
+    }
+    pub fn else_branch(self) -> Option<Block<'a>> {
+        self.blocks().nth(1)
+    }
+    fn blocks(self) -> AstChildren<'a, Block<'a>> {
+        children(self)
+    }
+}
+
+fn child_opt<'a, P: AstNode<'a>, C: AstNode<'a>>(parent: P) -> Option<C> {
+    children(parent).next()
+}
+
+fn children<'a, P: AstNode<'a>, C: AstNode<'a>>(parent: P) -> AstChildren<'a, C> {
+    AstChildren::new(parent.syntax())
+}
+
+
+#[derive(Debug)]
+pub struct AstChildren<'a, N> {
+    inner: SyntaxNodeChildren<RefRoot<'a>>,
+    ph: PhantomData<N>,
+}
+
+impl<'a, N> AstChildren<'a, N> {
+    fn new(parent: SyntaxNodeRef<'a>) -> Self {
+        AstChildren {
+            inner: parent.children(),
+            ph: PhantomData,
+        }
+    }
+}
+
+impl<'a, N: AstNode<'a>> Iterator for AstChildren<'a, N> {
+    type Item = N;
+    fn next(&mut self) -> Option<N> {
+        loop {
+            match N::cast(self.inner.next()?) {
+                Some(n) => return Some(n),
+                None => (),
+            }
+        }
+    }
+}