7 files changed, 134 insertions, 52 deletions

diff --git a/libeditor/src/lib.rs b/libeditor/src/lib.rs
index 387859d4a..e7cc6a696 100644
--- a/libeditor/src/lib.rs
+++ b/libeditor/src/lib.rs
@@ -3,7 +3,7 @@ extern crate libsyntax2;
 mod extend_selection;
 
 use libsyntax2::{
-    SyntaxNodeRef,
+    SyntaxNodeRef, AstNode,
     algo::walk,
     SyntaxKind::*,
 };
diff --git a/src/ast/generated.rs b/src/ast/generated.rs
new file mode 100644
index 000000000..612b04f86
--- /dev/null
+++ b/src/ast/generated.rs
@@ -0,0 +1,54 @@
+use std::sync::Arc;
+use {
+    SyntaxNode, SyntaxRoot, TreeRoot, AstNode,
+    SyntaxKind::*,
+};
+
+
+#[derive(Debug)]
+pub struct File<R: TreeRoot = Arc<SyntaxRoot>> {
+    syntax: SyntaxNode<R>,
+}
+
+impl<R: TreeRoot> AstNode<R> for File<R> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self> {
+        match syntax.kind() {
+            FILE => Some(File { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode<R> { &self.syntax }
+}
+
+
+#[derive(Debug)]
+pub struct FnItem<R: TreeRoot = Arc<SyntaxRoot>> {
+    syntax: SyntaxNode<R>,
+}
+
+impl<R: TreeRoot> AstNode<R> for FnItem<R> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self> {
+        match syntax.kind() {
+            FN_ITEM => Some(FnItem { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode<R> { &self.syntax }
+}
+
+
+#[derive(Debug)]
+pub struct Name<R: TreeRoot = Arc<SyntaxRoot>> {
+    syntax: SyntaxNode<R>,
+}
+
+impl<R: TreeRoot> AstNode<R> for Name<R> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self> {
+        match syntax.kind() {
+            NAME => Some(Name { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode<R> { &self.syntax }
+}
+
diff --git a/src/ast/generated.rs.tera b/src/ast/generated.rs.tera
new file mode 100644
index 000000000..f2559383a
--- /dev/null
+++ b/src/ast/generated.rs.tera
@@ -0,0 +1,22 @@
+use std::sync::Arc;
+use {
+    SyntaxNode, SyntaxRoot, TreeRoot, AstNode,
+    SyntaxKind::*,
+};
+{% for node in ast %}
+{% set Name = node.kind | camel  %}
+#[derive(Debug)]
+pub struct {{ Name }}<R: TreeRoot = Arc<SyntaxRoot>> {
+    syntax: SyntaxNode<R>,
+}
+
+impl<R: TreeRoot> AstNode<R> for {{ Name }}<R> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self> {
+        match syntax.kind() {
+            {{ node.kind }} => Some({{ Name }} { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode<R> { &self.syntax }
+}
+{% endfor %}
diff --git a/src/ast.rs b/src/ast/mod.rs
index a595b9324..dc7e006c9 100644
--- a/src/ast.rs
+++ b/src/ast/mod.rs
@@ -1,57 +1,41 @@
+mod generated;
+
 use std::sync::Arc;
 use {
     SyntaxNode, SyntaxRoot, TreeRoot,
     SyntaxKind::*,
 };
+pub use self::generated::*;
 
-#[derive(Debug)]
-pub struct File<R: TreeRoot = Arc<SyntaxRoot>> {
-    syntax: SyntaxNode<R>,
-}
-
-#[derive(Debug)]
-pub struct Function<R: TreeRoot = Arc<SyntaxRoot>> {
-    syntax: SyntaxNode<R>,
+pub trait AstNode<R: TreeRoot>: Sized {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self>;
+    fn syntax(&self) -> &SyntaxNode<R>;
 }
 
-#[derive(Debug)]
-pub struct Name<R: TreeRoot = Arc<SyntaxRoot>> {
-    syntax: SyntaxNode<R>,
-}
-
-
 impl File<Arc<SyntaxRoot>> {
     pub fn parse(text: &str) -> Self {
-        File {
-            syntax: ::parse(text),
-        }
+        File::cast(::parse(text)).unwrap()
     }
 }
 
 impl<R: TreeRoot> File<R> {
-    pub fn functions<'a>(&'a self) -> impl Iterator<Item = Function<R>> + 'a {
-        self.syntax
+    pub fn functions<'a>(&'a self) -> impl Iterator<Item = FnItem<R>> + 'a {
+        self.syntax()
             .children()
-            .filter(|node| node.kind() == FN_ITEM)
-            .map(|node| Function { syntax: node })
+            .filter_map(FnItem::cast)
     }
 }
 
-impl<R: TreeRoot> Function<R> {
-    pub fn syntax(&self) -> SyntaxNode<R> {
-        self.syntax.clone()
-    }
-
+impl<R: TreeRoot> FnItem<R> {
     pub fn name(&self) -> Option<Name<R>> {
-        self.syntax
+        self.syntax()
             .children()
-            .filter(|node| node.kind() == NAME)
-            .map(|node| Name { syntax: node })
+            .filter_map(Name::cast)
             .next()
     }
 
     pub fn has_atom_attr(&self, atom: &str) -> bool {
-        self.syntax
+        self.syntax()
             .children()
             .filter(|node| node.kind() == ATTR)
             .any(|attr| {
@@ -81,14 +65,6 @@ impl<R: TreeRoot> Function<R> {
 
 impl<R: TreeRoot> Name<R> {
     pub fn text(&self) -> String {
-        self.syntax.text()
-    }
-}
-
-
-
-impl<R: TreeRoot> File<R> {
-    pub fn syntax(&self) -> SyntaxNode<R> {
-        self.syntax.clone()
+        self.syntax().text()
     }
 }
diff --git a/src/grammar.ron b/src/grammar.ron
index 0443dd798..b6a870d84 100644
--- a/src/grammar.ron
+++ b/src/grammar.ron
@@ -212,5 +212,16 @@ Grammar(
         "PARAM",
         "SELF_PARAM",
         "ARG_LIST",
+    ],
+    ast: [
+        (
+            kind: "FILE"
+        ),
+        (
+            kind: "FN_ITEM"
+        ),
+        (
+            kind: "NAME"
+        ),
     ]
 )
diff --git a/src/lib.rs b/src/lib.rs
index 91b0c9c55..d1e690bb2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -41,7 +41,7 @@ mod yellow;
 pub mod utils;
 
 pub use {
-    ast::File,
+    ast::{AstNode, File},
     lexer::{tokenize, Token},
     syntax_kinds::SyntaxKind,
     text_unit::{TextRange, TextUnit},
diff --git a/tools/src/main.rs b/tools/src/main.rs
index 714158f55..b5c966f74 100644
--- a/tools/src/main.rs
+++ b/tools/src/main.rs
@@ -23,6 +23,8 @@ const INLINE_TESTS_DIR: &str = "tests/data/parser/inline";
 const GRAMMAR: &str = "./src/grammar.ron";
 const SYNTAX_KINDS: &str = "./src/syntax_kinds/generated.rs";
 const SYNTAX_KINDS_TEMPLATE: &str = "./src/syntax_kinds/generated.rs.tera";
+const AST: &str = "./src/ast/generated.rs";
+const AST_TEMPLATE: &str = "./src/ast/generated.rs.tera";
 
 fn main() -> Result<()> {
     let matches = App::new("tasks")
@@ -47,10 +49,16 @@ fn main() -> Result<()> {
 
 fn run_gen_command(name: &str, verify: bool) -> Result<()> {
     match name {
-        "gen-kinds" => update(Path::new(SYNTAX_KINDS), &get_kinds()?, verify),
-        "gen-tests" => gen_tests(verify),
+        "gen-kinds" => {
+            update(Path::new(SYNTAX_KINDS), &render_template(SYNTAX_KINDS_TEMPLATE)?, verify)?;
+            update(Path::new(AST), &render_template(AST_TEMPLATE)?, verify)?;
+        },
+        "gen-tests" => {
+            gen_tests(verify)?
+        },
         _ => unreachable!(),
     }
+    Ok(())
 }
 
 fn update(path: &Path, contents: &str, verify: bool) -> Result<()> {
@@ -68,13 +76,30 @@ fn update(path: &Path, contents: &str, verify: bool) -> Result<()> {
     Ok(())
 }
 
-fn get_kinds() -> Result<String> {
-    let grammar = grammar()?;
-    let template = fs::read_to_string(SYNTAX_KINDS_TEMPLATE)?;
+fn render_template(template: &str) -> Result<String> {
+    let grammar: ron::value::Value = {
+        let text = fs::read_to_string(GRAMMAR)?;
+        ron::de::from_str(&text)?
+    };
+    let template = fs::read_to_string(template)?;
     let mut tera = tera::Tera::default();
     tera.add_raw_template("grammar", &template)
         .map_err(|e| format_err!("template error: {:?}", e))?;
     tera.register_global_function("concat", Box::new(concat));
+    tera.register_filter("camel", |arg, _| {
+        Ok(arg.as_str().unwrap()
+            .split("_")
+            .flat_map(|word| {
+                word.chars()
+                    .next().unwrap()
+                    .to_uppercase()
+                    .chain(
+                        word.chars().skip(1).flat_map(|c| c.to_lowercase())
+                    )
+            })
+            .collect::<String>()
+            .into())
+    });
     let ret = tera
         .render("grammar", &grammar)
         .map_err(|e| format_err!("template error: {:?}", e))?;
@@ -94,12 +119,6 @@ fn get_kinds() -> Result<String> {
     }
 }
 
-fn grammar() -> Result<ron::value::Value> {
-    let text = fs::read_to_string(GRAMMAR)?;
-    let ret = ron::de::from_str(&text)?;
-    Ok(ret)
-}
-
 fn gen_tests(verify: bool) -> Result<()> {
     let tests = tests_from_dir(Path::new(GRAMMAR_DIR))?;