Switch ast declaration from ron to a macro

5 files changed, 717 insertions, 139 deletions

diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 65cabf005..72dd5e581 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -13,6 +13,4 @@ walkdir = "2.1.3"
 pico-args = "0.3.0"
 quote = "1.0.2"
 proc-macro2 = "1.0.1"
-ron = "0.5.1"
-serde = { version = "1.0.0", features = ["derive"] }
 anyhow = "1.0.19"
diff --git a/xtask/src/ast_src.rs b/xtask/src/ast_src.rs
new file mode 100644
index 000000000..d494a4a38
--- /dev/null
+++ b/xtask/src/ast_src.rs
@@ -0,0 +1,618 @@
+pub(crate) struct KindsSrc<'a> {
+    pub(crate) punct: &'a [(&'a str, &'a str)],
+    pub(crate) keywords: &'a [&'a str],
+    pub(crate) contextual_keywords: &'a [&'a str],
+    pub(crate) literals: &'a [&'a str],
+    pub(crate) tokens: &'a [&'a str],
+    pub(crate) nodes: &'a [&'a str],
+}
+
+pub(crate) const KINDS_SRC: KindsSrc = KindsSrc {
+    punct: &[
+        (";", "SEMI"),
+        (",", "COMMA"),
+        ("(", "L_PAREN"),
+        (")", "R_PAREN"),
+        ("{", "L_CURLY"),
+        ("}", "R_CURLY"),
+        ("[", "L_BRACK"),
+        ("]", "R_BRACK"),
+        ("<", "L_ANGLE"),
+        (">", "R_ANGLE"),
+        ("@", "AT"),
+        ("#", "POUND"),
+        ("~", "TILDE"),
+        ("?", "QUESTION"),
+        ("$", "DOLLAR"),
+        ("&", "AMP"),
+        ("|", "PIPE"),
+        ("+", "PLUS"),
+        ("*", "STAR"),
+        ("/", "SLASH"),
+        ("^", "CARET"),
+        ("%", "PERCENT"),
+        ("_", "UNDERSCORE"),
+        (".", "DOT"),
+        ("..", "DOTDOT"),
+        ("...", "DOTDOTDOT"),
+        ("..=", "DOTDOTEQ"),
+        (":", "COLON"),
+        ("::", "COLONCOLON"),
+        ("=", "EQ"),
+        ("==", "EQEQ"),
+        ("=>", "FAT_ARROW"),
+        ("!", "EXCL"),
+        ("!=", "NEQ"),
+        ("-", "MINUS"),
+        ("->", "THIN_ARROW"),
+        ("<=", "LTEQ"),
+        (">=", "GTEQ"),
+        ("+=", "PLUSEQ"),
+        ("-=", "MINUSEQ"),
+        ("|=", "PIPEEQ"),
+        ("&=", "AMPEQ"),
+        ("^=", "CARETEQ"),
+        ("/=", "SLASHEQ"),
+        ("*=", "STAREQ"),
+        ("%=", "PERCENTEQ"),
+        ("&&", "AMPAMP"),
+        ("||", "PIPEPIPE"),
+        ("<<", "SHL"),
+        (">>", "SHR"),
+        ("<<=", "SHLEQ"),
+        (">>=", "SHREQ"),
+    ],
+    keywords: &[
+        "as", "async", "await", "box", "break", "const", "continue", "crate", "dyn", "else",
+        "enum", "extern", "false", "fn", "for", "if", "impl", "in", "let", "loop", "macro",
+        "match", "mod", "move", "mut", "pub", "ref", "return", "self", "static", "struct", "super",
+        "trait", "true", "try", "type", "unsafe", "use", "where", "while",
+    ],
+    contextual_keywords: &["auto", "default", "existential", "union"],
+    literals: &[
+        "INT_NUMBER",
+        "FLOAT_NUMBER",
+        "CHAR",
+        "BYTE",
+        "STRING",
+        "RAW_STRING",
+        "BYTE_STRING",
+        "RAW_BYTE_STRING",
+    ],
+    tokens: &[
+        "ERROR",
+        "IDENT",
+        "WHITESPACE",
+        "LIFETIME",
+        "COMMENT",
+        "SHEBANG",
+        "L_DOLLAR",
+        "R_DOLLAR",
+    ],
+    nodes: &[
+        "SOURCE_FILE",
+        "STRUCT_DEF",
+        "UNION_DEF",
+        "ENUM_DEF",
+        "FN_DEF",
+        "RET_TYPE",
+        "EXTERN_CRATE_ITEM",
+        "MODULE",
+        "USE_ITEM",
+        "STATIC_DEF",
+        "CONST_DEF",
+        "TRAIT_DEF",
+        "IMPL_BLOCK",
+        "TYPE_ALIAS_DEF",
+        "MACRO_CALL",
+        "TOKEN_TREE",
+        "MACRO_DEF",
+        "PAREN_TYPE",
+        "TUPLE_TYPE",
+        "NEVER_TYPE",
+        "PATH_TYPE",
+        "POINTER_TYPE",
+        "ARRAY_TYPE",
+        "SLICE_TYPE",
+        "REFERENCE_TYPE",
+        "PLACEHOLDER_TYPE",
+        "FN_POINTER_TYPE",
+        "FOR_TYPE",
+        "IMPL_TRAIT_TYPE",
+        "DYN_TRAIT_TYPE",
+        "REF_PAT",
+        "BOX_PAT",
+        "BIND_PAT",
+        "PLACEHOLDER_PAT",
+        "DOT_DOT_PAT",
+        "PATH_PAT",
+        "RECORD_PAT",
+        "RECORD_FIELD_PAT_LIST",
+        "RECORD_FIELD_PAT",
+        "TUPLE_STRUCT_PAT",
+        "TUPLE_PAT",
+        "SLICE_PAT",
+        "RANGE_PAT",
+        "LITERAL_PAT",
+        // atoms
+        "TUPLE_EXPR",
+        "ARRAY_EXPR",
+        "PAREN_EXPR",
+        "PATH_EXPR",
+        "LAMBDA_EXPR",
+        "IF_EXPR",
+        "WHILE_EXPR",
+        "CONDITION",
+        "LOOP_EXPR",
+        "FOR_EXPR",
+        "CONTINUE_EXPR",
+        "BREAK_EXPR",
+        "LABEL",
+        "BLOCK_EXPR",
+        "RETURN_EXPR",
+        "MATCH_EXPR",
+        "MATCH_ARM_LIST",
+        "MATCH_ARM",
+        "MATCH_GUARD",
+        "RECORD_LIT",
+        "RECORD_FIELD_LIST",
+        "RECORD_FIELD",
+        "TRY_BLOCK_EXPR",
+        "BOX_EXPR",
+        // postfix
+        "CALL_EXPR",
+        "INDEX_EXPR",
+        "METHOD_CALL_EXPR",
+        "FIELD_EXPR",
+        "AWAIT_EXPR",
+        "TRY_EXPR",
+        "CAST_EXPR",
+        // unary
+        "REF_EXPR",
+        "PREFIX_EXPR",
+        "RANGE_EXPR", // just weird
+        "BIN_EXPR",
+        "BLOCK",
+        "EXTERN_BLOCK",
+        "EXTERN_ITEM_LIST",
+        "ENUM_VARIANT",
+        "RECORD_FIELD_DEF_LIST",
+        "RECORD_FIELD_DEF",
+        "TUPLE_FIELD_DEF_LIST",
+        "TUPLE_FIELD_DEF",
+        "ENUM_VARIANT_LIST",
+        "ITEM_LIST",
+        "ATTR",
+        "META_ITEM", // not an item actually
+        "USE_TREE",
+        "USE_TREE_LIST",
+        "PATH",
+        "PATH_SEGMENT",
+        "LITERAL",
+        "ALIAS",
+        "VISIBILITY",
+        "WHERE_CLAUSE",
+        "WHERE_PRED",
+        "ABI",
+        "NAME",
+        "NAME_REF",
+        "LET_STMT",
+        "EXPR_STMT",
+        "TYPE_PARAM_LIST",
+        "LIFETIME_PARAM",
+        "TYPE_PARAM",
+        "CONST_PARAM",
+        "TYPE_ARG_LIST",
+        "LIFETIME_ARG",
+        "TYPE_ARG",
+        "ASSOC_TYPE_ARG",
+        "PARAM_LIST",
+        "PARAM",
+        "SELF_PARAM",
+        "ARG_LIST",
+        "TYPE_BOUND",
+        "TYPE_BOUND_LIST",
+        // macro related
+        "MACRO_ITEMS",
+        "MACRO_STMTS",
+    ],
+};
+
+pub(crate) struct AstSrc<'a> {
+    pub(crate) nodes: &'a [AstNodeSrc<'a>],
+    pub(crate) enums: &'a [AstEnumSrc<'a>],
+}
+
+pub(crate) struct AstNodeSrc<'a> {
+    pub(crate) name: &'a str,
+    pub(crate) traits: &'a [&'a str],
+    pub(crate) fields: &'a [(&'a str, FieldSrc<&'a str>)],
+}
+
+pub(crate) enum FieldSrc<T> {
+    Shorthand,
+    Optional(T),
+    Many(T),
+}
+
+pub(crate) struct AstEnumSrc<'a> {
+    pub(crate) name: &'a str,
+    pub(crate) traits: &'a [&'a str],
+    pub(crate) variants: &'a [&'a str],
+}
+
+macro_rules! ast_nodes {
+    ($(
+        struct $name:ident$(: $($trait:ident),*)? {
+            $($field_name:ident $(: $ty:tt)?),*$(,)?
+        }
+    )*) => {
+        [$(
+            AstNodeSrc {
+                name: stringify!($name),
+                traits: &[$($(stringify!($trait)),*)?],
+                fields: &[$(
+                    (stringify!($field_name), field_ty!($field_name $($ty)?))
+                ),*],
+
+            }
+        ),*]
+    };
+}
+
+macro_rules! field_ty {
+    ($field_name:ident) => {
+        FieldSrc::Shorthand
+    };
+    ($field_name:ident [$ty:ident]) => {
+        FieldSrc::Many(stringify!($ty))
+    };
+    ($field_name:ident $ty:ident) => {
+        FieldSrc::Optional(stringify!($ty))
+    };
+}
+
+macro_rules! ast_enums {
+    ($(
+        enum $name:ident $(: $($trait:ident),*)? {
+            $($variant:ident),*$(,)?
+        }
+    )*) => {
+        [$(
+            AstEnumSrc {
+                name: stringify!($name),
+                traits: &[$($(stringify!($trait)),*)?],
+                variants: &[$(stringify!($variant)),*],
+
+            }
+        ),*]
+    };
+}
+
+pub(crate) const AST_SRC: AstSrc = AstSrc {
+    nodes: &ast_nodes! {
+        struct SourceFile: ModuleItemOwner, FnDefOwner {
+            modules: [Module],
+        }
+
+        struct FnDef: VisibilityOwner, NameOwner, TypeParamsOwner, DocCommentsOwner, AttrsOwner {
+            ParamList,
+            RetType,
+            body: BlockExpr,
+        }
+
+        struct RetType { TypeRef }
+
+        struct StructDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner {
+        }
+
+        struct UnionDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner {
+            RecordFieldDefList,
+        }
+
+        struct RecordFieldDefList { fields: [RecordFieldDef] }
+        struct RecordFieldDef: VisibilityOwner, NameOwner, AttrsOwner, DocCommentsOwner, TypeAscriptionOwner { }
+
+        struct TupleFieldDefList { fields: [TupleFieldDef] }
+        struct TupleFieldDef: VisibilityOwner, AttrsOwner {
+            TypeRef,
+        }
+
+        struct EnumDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner {
+            variant_list: EnumVariantList,
+        }
+        struct EnumVariantList {
+            variants: [EnumVariant],
+        }
+        struct EnumVariant: NameOwner, DocCommentsOwner, AttrsOwner {
+            Expr
+        }
+
+        struct TraitDef: VisibilityOwner, NameOwner, AttrsOwner, DocCommentsOwner, TypeParamsOwner, TypeBoundsOwner {
+            ItemList,
+        }
+
+        struct Module: VisibilityOwner, NameOwner, AttrsOwner, DocCommentsOwner {
+            ItemList,
+        }
+
+        struct ItemList: FnDefOwner, ModuleItemOwner {
+            impl_items: [ImplItem],
+        }
+
+        struct ConstDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner, TypeAscriptionOwner {
+            body: Expr,
+        }
+
+        struct StaticDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner, TypeAscriptionOwner {
+            body: Expr,
+        }
+
+        struct TypeAliasDef: VisibilityOwner, NameOwner, TypeParamsOwner, AttrsOwner, DocCommentsOwner, TypeBoundsOwner {
+            TypeRef,
+        }
+
+        struct ImplBlock: TypeParamsOwner, AttrsOwner {
+            ItemList,
+        }
+
+        struct ParenType { TypeRef }
+        struct TupleType { fields: [TypeRef] }
+        struct NeverType { }
+        struct PathType { Path }
+        struct PointerType { TypeRef }
+        struct ArrayType { TypeRef, Expr }
+        struct SliceType { TypeRef }
+        struct ReferenceType { TypeRef }
+        struct PlaceholderType {  }
+        struct FnPointerType { ParamList, RetType }
+        struct ForType { TypeRef }
+        struct ImplTraitType: TypeBoundsOwner {}
+        struct DynTraitType: TypeBoundsOwner {}
+
+        struct TupleExpr { exprs: [Expr] }
+        struct ArrayExpr { exprs: [Expr] }
+        struct ParenExpr { Expr }
+        struct PathExpr  { Path }
+        struct LambdaExpr {
+            ParamList,
+            RetType,
+            body: Expr,
+        }
+        struct IfExpr { Condition }
+        struct LoopExpr: LoopBodyOwner { }
+        struct TryBlockExpr { body: BlockExpr }
+        struct ForExpr: LoopBodyOwner {
+            Pat,
+            iterable: Expr,
+        }
+        struct WhileExpr: LoopBodyOwner { Condition }
+        struct ContinueExpr {}
+        struct BreakExpr { Expr }
+        struct Label {}
+        struct BlockExpr { Block  }
+        struct ReturnExpr { Expr }
+        struct CallExpr: ArgListOwner { Expr }
+        struct MethodCallExpr: ArgListOwner {
+            Expr, NameRef, TypeArgList,
+        }
+        struct IndexExpr {}
+        struct FieldExpr { Expr, NameRef }
+        struct AwaitExpr { Expr }
+        struct TryExpr { Expr }
+        struct CastExpr { Expr, TypeRef }
+        struct RefExpr { Expr }
+        struct PrefixExpr { Expr }
+        struct BoxExpr { Expr }
+        struct RangeExpr {}
+        struct BinExpr {}
+        struct Literal {}
+
+        struct MatchExpr { Expr, MatchArmList }
+        struct MatchArmList: AttrsOwner { arms: [MatchArm] }
+        struct MatchArm: AttrsOwner {
+            pats: [Pat],
+            guard: MatchGuard,
+            Expr,
+         }
+        struct MatchGuard { Expr }
+
+        struct RecordLit { Path, RecordFieldList }
+        struct RecordFieldList {
+            fields: [RecordField],
+            spread: Expr,
+         }
+        struct RecordField { NameRef, Expr }
+
+        struct RefPat { Pat }
+        struct BoxPat { Pat }
+        struct BindPat: NameOwner { Pat }
+        struct PlaceholderPat { }
+        struct DotDotPat { }
+        struct PathPat {  Path }
+        struct SlicePat {}
+        struct RangePat {}
+        struct LiteralPat { Literal }
+
+        struct RecordPat { RecordFieldPatList, Path }
+        struct RecordFieldPatList {
+            record_field_pats: [RecordFieldPat],
+            bind_pats: [BindPat],
+        }
+        struct RecordFieldPat: NameOwner { Pat }
+
+        struct TupleStructPat { Path, args: [Pat] }
+        struct TuplePat { args: [Pat] }
+
+        struct Visibility {}
+        struct Name {}
+        struct NameRef {}
+
+        struct MacroCall: NameOwner, AttrsOwner,DocCommentsOwner {
+            TokenTree, Path
+        }
+        struct Attr { Path, input: AttrInput }
+        struct TokenTree {}
+        struct TypeParamList {
+            type_params: [TypeParam],
+            lifetime_params: [LifetimeParam],
+        }
+        struct TypeParam: NameOwner, AttrsOwner, TypeBoundsOwner {
+            default_type: TypeRef,
+        }
+        struct ConstParam: NameOwner, AttrsOwner, TypeAscriptionOwner {
+            default_val: Expr,
+        }
+        struct LifetimeParam: AttrsOwner { }
+        struct TypeBound { TypeRef}
+        struct TypeBoundList { bounds: [TypeBound] }
+        struct WherePred: TypeBoundsOwner { TypeRef }
+        struct WhereClause { predicates: [WherePred] }
+        struct ExprStmt { Expr }
+        struct LetStmt: TypeAscriptionOwner {
+            Pat,
+            initializer: Expr,
+        }
+        struct Condition { Pat, Expr }
+        struct Block: AttrsOwner, ModuleItemOwner {
+            statements: [Stmt],
+            Expr,
+        }
+        struct ParamList {
+            SelfParam,
+            params: [Param],
+        }
+        struct SelfParam: TypeAscriptionOwner, AttrsOwner { }
+        struct Param: TypeAscriptionOwner, AttrsOwner {
+            Pat,
+        }
+        struct UseItem: AttrsOwner, VisibilityOwner {
+            UseTree,
+        }
+        struct UseTree {
+            Path, UseTreeList, Alias
+        }
+        struct Alias: NameOwner { }
+        struct UseTreeList { use_trees: [UseTree] }
+        struct ExternCrateItem: AttrsOwner, VisibilityOwner {
+            NameRef, Alias,
+        }
+        struct ArgList {
+            args: [Expr],
+        }
+        struct Path {
+            segment: PathSegment,
+            qualifier: Path,
+        }
+        struct PathSegment {
+            NameRef, TypeArgList, ParamList, RetType, PathType,
+        }
+        struct TypeArgList {
+            type_args: [TypeArg],
+            lifetime_args: [LifetimeArg],
+            assoc_type_args: [AssocTypeArg],
+        }
+        struct TypeArg { TypeRef }
+        struct AssocTypeArg { NameRef, TypeRef }
+        struct LifetimeArg {}
+
+        struct MacroItems: ModuleItemOwner, FnDefOwner { }
+
+        struct MacroStmts {
+            statements: [Stmt],
+            Expr,
+        }
+    },
+    enums: &ast_enums! {
+        enum NominalDef: NameOwner, TypeParamsOwner, AttrsOwner {
+            StructDef, EnumDef, UnionDef,
+        }
+
+        enum TypeRef {
+            ParenType,
+            TupleType,
+            NeverType,
+            PathType,
+            PointerType,
+            ArrayType,
+            SliceType,
+            ReferenceType,
+            PlaceholderType,
+            FnPointerType,
+            ForType,
+            ImplTraitType,
+            DynTraitType,
+        }
+
+        enum ModuleItem: AttrsOwner, VisibilityOwner {
+            StructDef,
+            UnionDef,
+            EnumDef,
+            FnDef,
+            TraitDef,
+            TypeAliasDef,
+            ImplBlock,
+            UseItem,
+            ExternCrateItem,
+            ConstDef,
+            StaticDef,
+            Module,
+        }
+
+        enum ImplItem: AttrsOwner {
+            FnDef, TypeAliasDef, ConstDef,
+        }
+
+        enum Expr {
+            TupleExpr,
+            ArrayExpr,
+            ParenExpr,
+            PathExpr,
+            LambdaExpr,
+            IfExpr,
+            LoopExpr,
+            ForExpr,
+            WhileExpr,
+            ContinueExpr,
+            BreakExpr,
+            Label,
+            BlockExpr,
+            ReturnExpr,
+            MatchExpr,
+            RecordLit,
+            CallExpr,
+            IndexExpr,
+            MethodCallExpr,
+            FieldExpr,
+            AwaitExpr,
+            TryExpr,
+            TryBlockExpr,
+            CastExpr,
+            RefExpr,
+            PrefixExpr,
+            RangeExpr,
+            BinExpr,
+            Literal,
+            MacroCall,
+            BoxExpr,
+        }
+
+        enum Pat {
+            RefPat,
+            BoxPat,
+            BindPat,
+            PlaceholderPat,
+            DotDotPat,
+            PathPat,
+            RecordPat,
+            TupleStructPat,
+            TuplePat,
+            SlicePat,
+            RangePat,
+            LiteralPat,
+        }
+
+        enum AttrInput { Literal, TokenTree }
+        enum Stmt { ExprStmt, LetStmt }
+    },
+};
diff --git a/xtask/src/codegen.rs b/xtask/src/codegen.rs
index 53f524f42..158cfc2d6 100644
--- a/xtask/src/codegen.rs
+++ b/xtask/src/codegen.rs
@@ -24,7 +24,6 @@ pub use self::{
     gen_syntax::generate_syntax,
 };
 
-pub const GRAMMAR: &str = "crates/ra_syntax/src/grammar.ron";
 const GRAMMAR_DIR: &str = "crates/ra_parser/src/grammar";
 const OK_INLINE_TESTS_DIR: &str = "crates/ra_syntax/test_data/parser/inline/ok";
 const ERR_INLINE_TESTS_DIR: &str = "crates/ra_syntax/test_data/parser/inline/err";
diff --git a/xtask/src/codegen/gen_syntax.rs b/xtask/src/codegen/gen_syntax.rs
index 88f2ac0e3..0f50ca569 100644
--- a/xtask/src/codegen/gen_syntax.rs
+++ b/xtask/src/codegen/gen_syntax.rs
@@ -3,149 +3,142 @@
 //! Specifically, it generates the `SyntaxKind` enum and a number of newtype
 //! wrappers around `SyntaxNode` which implement `ra_syntax::AstNode`.
 
-use std::{collections::BTreeMap, fs};
-
 use proc_macro2::{Punct, Spacing};
 use quote::{format_ident, quote};
-use ron;
-use serde::Deserialize;
 
 use crate::{
+    ast_src::{AstSrc, FieldSrc, KindsSrc, AST_SRC, KINDS_SRC},
     codegen::{self, update, Mode},
     project_root, Result,
 };
 
 pub fn generate_syntax(mode: Mode) -> Result<()> {
-    let grammar = project_root().join(codegen::GRAMMAR);
-    let grammar: Grammar = {
-        let text = fs::read_to_string(grammar)?;
-        ron::de::from_str(&text)?
-    };
-
     let syntax_kinds_file = project_root().join(codegen::SYNTAX_KINDS);
-    let syntax_kinds = generate_syntax_kinds(&grammar)?;
+    let syntax_kinds = generate_syntax_kinds(KINDS_SRC)?;
     update(syntax_kinds_file.as_path(), &syntax_kinds, mode)?;
 
     let ast_file = project_root().join(codegen::AST);
-    let ast = generate_ast(&grammar)?;
+    let ast = generate_ast(AST_SRC)?;
     update(ast_file.as_path(), &ast, mode)?;
 
     Ok(())
 }
 
-fn generate_ast(grammar: &Grammar) -> Result<String> {
-    let nodes = grammar.ast.iter().map(|(name, ast_node)| {
-        let variants =
-            ast_node.variants.iter().map(|var| format_ident!("{}", var)).collect::<Vec<_>>();
-        let name = format_ident!("{}", name);
-
-        let adt = if variants.is_empty() {
-            let kind = format_ident!("{}", to_upper_snake_case(&name.to_string()));
-            quote! {
-                #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-                pub struct #name {
-                    pub(crate) syntax: SyntaxNode,
-                }
+fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
+    let nodes = grammar.nodes.iter().map(|node| {
+        let name = format_ident!("{}", node.name);
+        let kind = format_ident!("{}", to_upper_snake_case(&name.to_string()));
+        let traits = node.traits.iter().map(|trait_name| {
+            let trait_name = format_ident!("{}", trait_name);
+            quote!(impl ast::#trait_name for #name {})
+        });
 
-                impl AstNode for #name {
-                    fn can_cast(kind: SyntaxKind) -> bool {
-                        match kind {
-                            #kind => true,
-                            _ => false,
+        let methods = node.fields.iter().map(|(name, field)| {
+            let method_name = match field {
+                FieldSrc::Shorthand => format_ident!("{}", to_lower_snake_case(&name)),
+                _ => format_ident!("{}", name),
+            };
+            let ty = match field {
+                FieldSrc::Optional(ty) | FieldSrc::Many(ty) => ty,
+                FieldSrc::Shorthand => name,
+            };
+            let ty = format_ident!("{}", ty);
+
+            match field {
+                FieldSrc::Many(_) => {
+                    quote! {
+                        pub fn #method_name(&self) -> AstChildren<#ty> {
+                            AstChildren::new(&self.syntax)
                         }
                     }
-                    fn cast(syntax: SyntaxNode) -> Option<Self> {
-                        if Self::can_cast(syntax.kind()) { Some(Self { syntax }) } else { None }
+                }
+                FieldSrc::Optional(_) | FieldSrc::Shorthand => {
+                    quote! {
+                        pub fn #method_name(&self) -> Option<#ty> {
+                            AstChildren::new(&self.syntax).next()
+                        }
                     }
-                    fn syntax(&self) -> &SyntaxNode { &self.syntax }
                 }
             }
-        } else {
-            let kinds = variants
-                .iter()
-                .map(|name| format_ident!("{}", to_upper_snake_case(&name.to_string())))
-                .collect::<Vec<_>>();
-
-            quote! {
-                #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-                pub enum #name {
-                    #(#variants(#variants),)*
-                }
+        });
 
-                #(
-                impl From<#variants> for #name {
-                    fn from(node: #variants) -> #name {
-                        #name::#variants(node)
-                    }
-                }
-                )*
+        quote! {
+            #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+            pub struct #name {
+                pub(crate) syntax: SyntaxNode,
+            }
 
-                impl AstNode for #name {
-                    fn can_cast(kind: SyntaxKind) -> bool {
-                        match kind {
-                            #(#kinds)|* => true,
-                            _ => false,
-                        }
-                    }
-                    fn cast(syntax: SyntaxNode) -> Option<Self> {
-                        let res = match syntax.kind() {
-                            #(
-                            #kinds => #name::#variants(#variants { syntax }),
-                            )*
-                            _ => return None,
-                        };
-                        Some(res)
-                    }
-                    fn syntax(&self) -> &SyntaxNode {
-                        match self {
-                            #(
-                            #name::#variants(it) => &it.syntax,
-                            )*
-                        }
+            impl AstNode for #name {
+                fn can_cast(kind: SyntaxKind) -> bool {
+                    match kind {
+                        #kind => true,
+                        _ => false,
                     }
                 }
+                fn cast(syntax: SyntaxNode) -> Option<Self> {
+                    if Self::can_cast(syntax.kind()) { Some(Self { syntax }) } else { None }
+                }
+                fn syntax(&self) -> &SyntaxNode { &self.syntax }
             }
-        };
+            #(#traits)*
+
+            impl #name {
+                #(#methods)*
+            }
+        }
+    });
 
-        let traits = ast_node.traits.iter().map(|trait_name| {
+    let enums = grammar.enums.iter().map(|en| {
+        let variants = en.variants.iter().map(|var| format_ident!("{}", var)).collect::<Vec<_>>();
+        let name = format_ident!("{}", en.name);
+        let kinds = variants
+            .iter()
+            .map(|name| format_ident!("{}", to_upper_snake_case(&name.to_string())))
+            .collect::<Vec<_>>();
+        let traits = en.traits.iter().map(|trait_name| {
             let trait_name = format_ident!("{}", trait_name);
             quote!(impl ast::#trait_name for #name {})
         });
 
-        let collections = ast_node.collections.iter().map(|(name, kind)| {
-            let method_name = format_ident!("{}", name);
-            let kind = format_ident!("{}", kind);
-            quote! {
-                pub fn #method_name(&self) -> AstChildren<#kind> {
-                    AstChildren::new(&self.syntax)
-                }
+        quote! {
+            #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+            pub enum #name {
+                #(#variants(#variants),)*
             }
-        });
 
-        let options = ast_node.options.iter().map(|attr| {
-            let method_name = match attr {
-                Attr::Type(t) => format_ident!("{}", to_lower_snake_case(&t)),
-                Attr::NameType(n, _) => format_ident!("{}", n),
-            };
-            let ty = match attr {
-                Attr::Type(t) | Attr::NameType(_, t) => format_ident!("{}", t),
-            };
-            quote! {
-                pub fn #method_name(&self) -> Option<#ty> {
-                    AstChildren::new(&self.syntax).next()
+            #(
+            impl From<#variants> for #name {
+                fn from(node: #variants) -> #name {
+                    #name::#variants(node)
                 }
             }
-        });
-
-        quote! {
-            #adt
-
-            #(#traits)*
+            )*
 
-            impl #name {
-                #(#collections)*
-                #(#options)*
+            impl AstNode for #name {
+                fn can_cast(kind: SyntaxKind) -> bool {
+                    match kind {
+                        #(#kinds)|* => true,
+                        _ => false,
+                    }
+                }
+                fn cast(syntax: SyntaxNode) -> Option<Self> {
+                    let res = match syntax.kind() {
+                        #(
+                        #kinds => #name::#variants(#variants { syntax }),
+                        )*
+                        _ => return None,
+                    };
+                    Some(res)
+                }
+                fn syntax(&self) -> &SyntaxNode {
+                    match self {
+                        #(
+                        #name::#variants(it) => &it.syntax,
+                        )*
+                    }
+                }
             }
+            #(#traits)*
         }
     });
 
@@ -156,13 +149,14 @@ fn generate_ast(grammar: &Grammar) -> Result<String> {
         };
 
         #(#nodes)*
+        #(#enums)*
     };
 
     let pretty = codegen::reformat(ast)?;
     Ok(pretty)
 }
 
-fn generate_syntax_kinds(grammar: &Grammar) -> Result<String> {
+fn generate_syntax_kinds(grammar: KindsSrc<'_>) -> Result<String> {
     let (single_byte_tokens_values, single_byte_tokens): (Vec<_>, Vec<_>) = grammar
         .punct
         .iter()
@@ -274,38 +268,6 @@ fn generate_syntax_kinds(grammar: &Grammar) -> Result<String> {
     codegen::reformat(ast)
 }
 
-#[derive(Deserialize, Debug)]
-struct Grammar {
-    punct: Vec<(String, String)>,
-    keywords: Vec<String>,
-    contextual_keywords: Vec<String>,
-    literals: Vec<String>,
-    tokens: Vec<String>,
-    nodes: Vec<String>,
-    ast: BTreeMap<String, AstNode>,
-}
-
-#[derive(Deserialize, Debug)]
-struct AstNode {
-    #[serde(default)]
-    #[serde(rename = "enum")]
-    variants: Vec<String>,
-
-    #[serde(default)]
-    traits: Vec<String>,
-    #[serde(default)]
-    collections: Vec<(String, String)>,
-    #[serde(default)]
-    options: Vec<Attr>,
-}
-
-#[derive(Deserialize, Debug)]
-#[serde(untagged)]
-enum Attr {
-    Type(String),
-    NameType(String, String),
-}
-
 fn to_upper_snake_case(s: &str) -> String {
     let mut buf = String::with_capacity(s.len());
     let mut prev_is_upper = None;
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index 40a6682be..51a868dee 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -1,6 +1,7 @@
 //! FIXME: write short doc here
 
 pub mod codegen;
+mod ast_src;
 
 use anyhow::Context;
 pub use anyhow::Result;