1 files changed, 226 insertions, 31 deletions

diff --git a/xtask/src/codegen/gen_syntax.rs b/xtask/src/codegen/gen_syntax.rs
index 32afd47bc..b5594e3a9 100644
--- a/xtask/src/codegen/gen_syntax.rs
+++ b/xtask/src/codegen/gen_syntax.rs
@@ -3,6 +3,11 @@
 //! Specifically, it generates the `SyntaxKind` enum and a number of newtype
 //! wrappers around `SyntaxNode` which implement `ra_syntax::AstNode`.
 
+use std::{
+    borrow::Cow,
+    collections::{BTreeSet, HashSet},
+};
+
 use proc_macro2::{Punct, Spacing};
 use quote::{format_ident, quote};
 
@@ -17,14 +22,161 @@ pub fn generate_syntax(mode: Mode) -> Result<()> {
     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(AST_SRC)?;
-    update(ast_file.as_path(), &ast, mode)?;
+    let ast_nodes_file = project_root().join(codegen::AST_NODES);
+    let contents = generate_nodes(KINDS_SRC, AST_SRC)?;
+    update(ast_nodes_file.as_path(), &contents, mode)?;
+
+    let ast_tokens_file = project_root().join(codegen::AST_TOKENS);
+    let contents = generate_tokens(KINDS_SRC, AST_SRC)?;
+    update(ast_tokens_file.as_path(), &contents, mode)?;
 
     Ok(())
 }
 
-fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
+#[derive(Debug, Default, Clone)]
+struct ElementKinds {
+    kinds: BTreeSet<proc_macro2::Ident>,
+    has_nodes: bool,
+    has_tokens: bool,
+}
+
+fn generate_tokens(kinds: KindsSrc<'_>, grammar: AstSrc<'_>) -> Result<String> {
+    let all_token_kinds: Vec<_> = kinds
+        .punct
+        .into_iter()
+        .map(|(_, kind)| kind)
+        .copied()
+        .map(|x| x.into())
+        .chain(
+            kinds
+                .keywords
+                .into_iter()
+                .chain(kinds.contextual_keywords.into_iter())
+                .map(|name| Cow::Owned(format!("{}_KW", to_upper_snake_case(&name)))),
+        )
+        .chain(kinds.literals.into_iter().copied().map(|x| x.into()))
+        .chain(kinds.tokens.into_iter().copied().map(|x| x.into()))
+        .collect();
+
+    let tokens = all_token_kinds.iter().map(|kind_str| {
+        let kind_str = &**kind_str;
+        let kind = format_ident!("{}", kind_str);
+        let name = format_ident!("{}", to_pascal_case(kind_str));
+        quote! {
+            #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+            pub struct #name {
+                pub(crate) syntax: SyntaxToken,
+            }
+
+            impl std::fmt::Display for #name {
+                fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                    std::fmt::Display::fmt(&self.syntax, f)
+                }
+            }
+
+            impl AstToken for #name {
+                fn can_cast(kind: SyntaxKind) -> bool { kind == #kind }
+                fn cast(syntax: SyntaxToken) -> Option<Self> {
+                    if Self::can_cast(syntax.kind()) { Some(Self { syntax }) } else { None }
+                }
+                fn syntax(&self) -> &SyntaxToken { &self.syntax }
+            }
+        }
+    });
+
+    let enums = grammar.token_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<_>>();
+        assert!(en.traits.is_empty());
+
+        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)
+                    }
+                }
+                )*
+
+                impl std::fmt::Display for #name {
+                    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                        std::fmt::Display::fmt(self.syntax(), f)
+                    }
+                }
+
+                impl AstToken for #name {
+                    fn can_cast(kind: SyntaxKind) -> bool {
+                        match kind {
+                            #(#kinds)|* => true,
+                            _ => false,
+                        }
+                    }
+                    fn cast(syntax: SyntaxToken) -> Option<Self> {
+                        let res = match syntax.kind() {
+                            #(
+                            #kinds => #name::#variants(#variants { syntax }),
+                            )*
+                            _ => return None,
+                        };
+                        Some(res)
+                    }
+                    fn syntax(&self) -> &SyntaxToken {
+                        match self {
+                            #(
+                            #name::#variants(it) => &it.syntax,
+                            )*
+                        }
+                    }
+                }
+        }
+    });
+
+    crate::reformat(quote! {
+        use crate::{SyntaxToken, SyntaxKind::{self, *}, ast::AstToken};
+
+        #(#tokens)*
+        #(#enums)*
+    })
+}
+
+fn generate_nodes(kinds: KindsSrc<'_>, grammar: AstSrc<'_>) -> Result<String> {
+    let all_token_kinds: Vec<_> = kinds
+        .punct
+        .into_iter()
+        .map(|(_, kind)| kind)
+        .copied()
+        .map(|x| x.into())
+        .chain(
+            kinds
+                .keywords
+                .into_iter()
+                .chain(kinds.contextual_keywords.into_iter())
+                .map(|name| Cow::Owned(format!("{}_KW", to_upper_snake_case(&name)))),
+        )
+        .chain(kinds.literals.into_iter().copied().map(|x| x.into()))
+        .chain(kinds.tokens.into_iter().copied().map(|x| x.into()))
+        .collect();
+
+    let mut token_kinds = HashSet::new();
+    for kind in &all_token_kinds {
+        let kind = &**kind;
+        let name = to_pascal_case(kind);
+        token_kinds.insert(name);
+    }
+
+    for en in grammar.token_enums {
+        token_kinds.insert(en.name.to_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()));
@@ -42,20 +194,31 @@ fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
                 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)
+                            support::children(&self.syntax)
                         }
                     }
                 }
                 FieldSrc::Optional(_) | FieldSrc::Shorthand => {
-                    quote! {
-                        pub fn #method_name(&self) -> Option<#ty> {
-                            AstChildren::new(&self.syntax).next()
+                    let is_token = token_kinds.contains(&ty.to_string());
+                    if is_token {
+                        let method_name = format_ident!("{}_token", method_name);
+                        quote! {
+                            pub fn #method_name(&self) -> Option<#ty> {
+                                support::token(&self.syntax)
+                            }
+                        }
+                    } else {
+                        quote! {
+                            pub fn #method_name(&self) -> Option<#ty> {
+                                support::child(&self.syntax)
+                            }
                         }
                     }
                 }
@@ -68,24 +231,16 @@ fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
                 pub(crate) syntax: SyntaxNode,
             }
 
-            impl std::fmt::Display for #name {
-                fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-                    std::fmt::Display::fmt(self.syntax(), f)
-                }
-            }
-
             impl AstNode for #name {
                 fn can_cast(kind: SyntaxKind) -> bool {
-                    match kind {
-                        #kind => true,
-                        _ => false,
-                    }
+                    kind == #kind
                 }
                 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 {
@@ -120,12 +275,6 @@ fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
             }
             )*
 
-            impl std::fmt::Display for #name {
-                fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-                    std::fmt::Display::fmt(self.syntax(), f)
-                }
-            }
-
             impl AstNode for #name {
                 fn can_cast(kind: SyntaxKind) -> bool {
                     match kind {
@@ -150,18 +299,48 @@ fn generate_ast(grammar: AstSrc<'_>) -> Result<String> {
                     }
                 }
             }
+
             #(#traits)*
         }
     });
 
+    let displays = grammar
+        .enums
+        .iter()
+        .map(|it| format_ident!("{}", it.name))
+        .chain(grammar.nodes.iter().map(|it| format_ident!("{}", it.name)))
+        .map(|name| {
+            quote! {
+                impl std::fmt::Display for #name {
+                    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                        std::fmt::Display::fmt(self.syntax(), f)
+                    }
+                }
+            }
+        });
+
+    let defined_nodes: HashSet<_> = grammar.nodes.iter().map(|node| node.name).collect();
+
+    for node in kinds
+        .nodes
+        .iter()
+        .map(|kind| to_pascal_case(*kind))
+        .filter(|name| !defined_nodes.contains(&**name))
+    {
+        eprintln!("Warning: node {} not defined in ast source", node);
+    }
+
     let ast = quote! {
         use crate::{
             SyntaxNode, SyntaxKind::{self, *},
-            ast::{self, AstNode, AstChildren},
+            ast::{self, AstNode, AstChildren, support},
         };
 
+        use super::tokens::*;
+
         #(#nodes)*
         #(#enums)*
+        #(#displays)*
     };
 
     let pretty = crate::reformat(ast)?;
@@ -282,12 +461,12 @@ fn generate_syntax_kinds(grammar: KindsSrc<'_>) -> Result<String> {
 
 fn to_upper_snake_case(s: &str) -> String {
     let mut buf = String::with_capacity(s.len());
-    let mut prev_is_upper = None;
+    let mut prev = false;
     for c in s.chars() {
-        if c.is_ascii_uppercase() && prev_is_upper == Some(false) {
+        if c.is_ascii_uppercase() && prev {
             buf.push('_')
         }
-        prev_is_upper = Some(c.is_ascii_uppercase());
+        prev = true;
 
         buf.push(c.to_ascii_uppercase());
     }
@@ -296,14 +475,30 @@ fn to_upper_snake_case(s: &str) -> String {
 
 fn to_lower_snake_case(s: &str) -> String {
     let mut buf = String::with_capacity(s.len());
-    let mut prev_is_upper = None;
+    let mut prev = false;
     for c in s.chars() {
-        if c.is_ascii_uppercase() && prev_is_upper == Some(false) {
+        if c.is_ascii_uppercase() && prev {
             buf.push('_')
         }
-        prev_is_upper = Some(c.is_ascii_uppercase());
+        prev = true;
 
         buf.push(c.to_ascii_lowercase());
     }
     buf
 }
+
+fn to_pascal_case(s: &str) -> String {
+    let mut buf = String::with_capacity(s.len());
+    let mut prev_is_underscore = true;
+    for c in s.chars() {
+        if c == '_' {
+            prev_is_underscore = true;
+        } else if prev_is_underscore {
+            buf.push(c.to_ascii_uppercase());
+            prev_is_underscore = false;
+        } else {
+            buf.push(c.to_ascii_lowercase());
+        }
+    }
+    buf
+}