Hash out ast structure

minirust.rs

@@ -1,3 +1,4 @@
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub struct NodeKind(u16);
 
 pub struct File {
@@ -67,8 +68,6 @@ impl<'f> Iterator for Children<'f> {
     }
 }
 
-
-
 pub const ERROR: NodeKind = NodeKind(0);
 pub const WHITESPACE: NodeKind = NodeKind(1);
 pub const STRUCT_KW: NodeKind = NodeKind(2);
@@ -82,4 +81,72 @@ pub const LINE_COMMENT: NodeKind = NodeKind(9);
 pub const FILE: NodeKind = NodeKind(10);
 pub const STRUCT_DEF: NodeKind = NodeKind(11);
 pub const FIELD_DEF: NodeKind = NodeKind(12);
-pub const TYPE: NodeKind = NodeKind(13);
+pub const TYPE_REF: NodeKind = NodeKind(13);
+
+
+pub trait AstNode<'f>: Copy + 'f {
+    fn new(node: Node<'f>) -> Option<Self>;
+    fn node(&self) -> Node<'f>;
+}
+
+pub fn child_of_kind<'f>(node: Node<'f>, kind: NodeKind) -> Option<Node<'f>> {
+    node.children().find(|child| child.kind() == kind)
+}
+
+pub fn ast_children<'f, A: AstNode<'f>>(node: Node<'f>) -> Box<Iterator<Item=A> + 'f> {
+    Box::new(node.children().filter_map(A::new))
+}
+
+#[derive(Clone, Copy)]
+pub struct StructDef<'f>(Node<'f>);
+
+#[derive(Clone, Copy)]
+pub struct FieldDef<'f>(Node<'f>);
+
+#[derive(Clone, Copy)]
+pub struct TypeRef<'f>(Node<'f>);
+
+pub trait NameOwner<'f>: AstNode<'f> {
+    fn name_ident(&self) -> Node<'f> {
+        child_of_kind(self.node(), IDENT).unwrap()
+    }
+
+    fn name(&self) -> &'f str { self.name_ident().text() }
+}
+
+
+impl<'f> AstNode<'f> for StructDef<'f> {
+    fn new(node: Node<'f>) -> Option<Self> {
+        if node.kind() == STRUCT_DEF { Some(StructDef(node)) } else { None }
+    }
+    fn node(&self) -> Node<'f> { self.0 }
+}
+
+impl<'f> AstNode<'f> for FieldDef<'f> {
+    fn new(node: Node<'f>) -> Option<Self> {
+        if node.kind() == FIELD_DEF { Some(FieldDef(node)) } else { None }
+    }
+    fn node(&self) -> Node<'f> { self.0 }
+}
+
+impl<'f> AstNode<'f> for TypeRef<'f> {
+    fn new(node: Node<'f>) -> Option<Self> {
+        if node.kind() == TYPE_REF { Some(TypeRef(node)) } else { None }
+    }
+    fn node(&self) -> Node<'f> { self.0 }
+}
+
+impl<'f> NameOwner<'f> for StructDef<'f> {}
+impl<'f> NameOwner<'f> for FieldDef<'f> {}
+
+impl<'f> StructDef<'f> {
+    pub fn fields(&self) -> Box<Iterator<Item=FieldDef<'f>> + 'f> {
+        ast_children(self.node())
+    }
+}
+
+impl<'f> FieldDef<'f> {
+    pub fn type_ref(&self) -> Option<TypeRef<'f>> {
+        ast_children(self.node()).next()
+    }
+}

rfc.md

@@ -150,7 +150,7 @@ FILE
 	  IDENT
 	  COLON
 	  WHITESPACE
-	  TYPE
+	  TYPE_REF
 	    IDENT
 	COMMA
 	WHITESPACE
@@ -180,7 +180,7 @@ Note several features of the tree:
   
 * The non-documenting comment is correctly attached to the following
   field.
-
+  
 
 
 # Drawbacks