1 files changed, 282 insertions, 0 deletions

diff --git a/crates/hir_expand/src/quote.rs b/crates/hir_expand/src/quote.rs
new file mode 100644
index 000000000..219bc2097
--- /dev/null
+++ b/crates/hir_expand/src/quote.rs
@@ -0,0 +1,282 @@
+//! A simplified version of quote-crate like quasi quote macro
+
+// A helper macro quote macro
+// FIXME:
+// 1. Not all puncts are handled
+// 2. #()* pattern repetition not supported now
+//    * But we can do it manually, see `test_quote_derive_copy_hack`
+#[doc(hidden)]
+#[macro_export]
+macro_rules! __quote {
+    () => {
+        Vec::<tt::TokenTree>::new()
+    };
+
+    ( @SUBTREE $delim:ident $($tt:tt)* ) => {
+        {
+            let children = $crate::__quote!($($tt)*);
+            tt::Subtree {
+                delimiter: Some(tt::Delimiter {
+                    kind: tt::DelimiterKind::$delim,
+                    id: tt::TokenId::unspecified(),
+                }),
+                token_trees: $crate::quote::IntoTt::to_tokens(children),
+            }
+        }
+    };
+
+    ( @PUNCT $first:literal ) => {
+        {
+            vec![
+                tt::Leaf::Punct(tt::Punct {
+                    char: $first,
+                    spacing: tt::Spacing::Alone,
+                    id: tt::TokenId::unspecified(),
+                }).into()
+            ]
+        }
+    };
+
+    ( @PUNCT $first:literal, $sec:literal ) => {
+        {
+            vec![
+                tt::Leaf::Punct(tt::Punct {
+                    char: $first,
+                    spacing: tt::Spacing::Joint,
+                    id: tt::TokenId::unspecified(),
+                }).into(),
+                tt::Leaf::Punct(tt::Punct {
+                    char: $sec,
+                    spacing: tt::Spacing::Alone,
+                    id: tt::TokenId::unspecified(),
+                }).into()
+            ]
+        }
+    };
+
+    // hash variable
+    ( # $first:ident $($tail:tt)* ) => {
+        {
+            let token = $crate::quote::ToTokenTree::to_token($first);
+            let mut tokens = vec![token.into()];
+            let mut tail_tokens = $crate::quote::IntoTt::to_tokens($crate::__quote!($($tail)*));
+            tokens.append(&mut tail_tokens);
+            tokens
+        }
+    };
+
+    ( ## $first:ident $($tail:tt)* ) => {
+        {
+            let mut tokens = $first.into_iter().map($crate::quote::ToTokenTree::to_token).collect::<Vec<tt::TokenTree>>();
+            let mut tail_tokens = $crate::quote::IntoTt::to_tokens($crate::__quote!($($tail)*));
+            tokens.append(&mut tail_tokens);
+            tokens
+        }
+    };
+
+    // Brace
+    ( { $($tt:tt)* } ) => { $crate::__quote!(@SUBTREE Brace $($tt)*) };
+    // Bracket
+    ( [ $($tt:tt)* ] ) => { $crate::__quote!(@SUBTREE Bracket $($tt)*) };
+    // Parenthesis
+    ( ( $($tt:tt)* ) ) => { $crate::__quote!(@SUBTREE Parenthesis $($tt)*) };
+
+    // Literal
+    ( $tt:literal ) => { vec![$crate::quote::ToTokenTree::to_token($tt).into()] };
+    // Ident
+    ( $tt:ident ) => {
+        vec![ {
+            tt::Leaf::Ident(tt::Ident {
+                text: stringify!($tt).into(),
+                id: tt::TokenId::unspecified(),
+            }).into()
+        }]
+    };
+
+    // Puncts
+    // FIXME: Not all puncts are handled
+    ( -> ) => {$crate::__quote!(@PUNCT '-', '>')};
+    ( & ) => {$crate::__quote!(@PUNCT '&')};
+    ( , ) => {$crate::__quote!(@PUNCT ',')};
+    ( : ) => {$crate::__quote!(@PUNCT ':')};
+    ( ; ) => {$crate::__quote!(@PUNCT ';')};
+    ( :: ) => {$crate::__quote!(@PUNCT ':', ':')};
+    ( . ) => {$crate::__quote!(@PUNCT '.')};
+    ( < ) => {$crate::__quote!(@PUNCT '<')};
+    ( > ) => {$crate::__quote!(@PUNCT '>')};
+
+    ( $first:tt $($tail:tt)+ ) => {
+        {
+            let mut tokens = $crate::quote::IntoTt::to_tokens($crate::__quote!($first));
+            let mut tail_tokens = $crate::quote::IntoTt::to_tokens($crate::__quote!($($tail)*));
+
+            tokens.append(&mut tail_tokens);
+            tokens
+        }
+    };
+}
+
+/// FIXME:
+/// It probably should implement in proc-macro
+#[macro_export]
+macro_rules! quote {
+    ( $($tt:tt)* ) => {
+        $crate::quote::IntoTt::to_subtree($crate::__quote!($($tt)*))
+    }
+}
+
+pub(crate) trait IntoTt {
+    fn to_subtree(self) -> tt::Subtree;
+    fn to_tokens(self) -> Vec<tt::TokenTree>;
+}
+
+impl IntoTt for Vec<tt::TokenTree> {
+    fn to_subtree(self) -> tt::Subtree {
+        tt::Subtree { delimiter: None, token_trees: self }
+    }
+
+    fn to_tokens(self) -> Vec<tt::TokenTree> {
+        self
+    }
+}
+
+impl IntoTt for tt::Subtree {
+    fn to_subtree(self) -> tt::Subtree {
+        self
+    }
+
+    fn to_tokens(self) -> Vec<tt::TokenTree> {
+        vec![tt::TokenTree::Subtree(self)]
+    }
+}
+
+pub(crate) trait ToTokenTree {
+    fn to_token(self) -> tt::TokenTree;
+}
+
+impl ToTokenTree for tt::TokenTree {
+    fn to_token(self) -> tt::TokenTree {
+        self
+    }
+}
+
+impl ToTokenTree for tt::Subtree {
+    fn to_token(self) -> tt::TokenTree {
+        self.into()
+    }
+}
+
+macro_rules! impl_to_to_tokentrees {
+    ($($ty:ty => $this:ident $im:block);*) => {
+        $(
+            impl ToTokenTree for $ty {
+                fn to_token($this) -> tt::TokenTree {
+                    let leaf: tt::Leaf = $im.into();
+                    leaf.into()
+                }
+            }
+
+            impl ToTokenTree for &$ty {
+                fn to_token($this) -> tt::TokenTree {
+                    let leaf: tt::Leaf = $im.clone().into();
+                    leaf.into()
+                }
+            }
+        )*
+    }
+}
+
+impl_to_to_tokentrees! {
+    u32 => self { tt::Literal{text: self.to_string().into(), id: tt::TokenId::unspecified()} };
+    usize => self { tt::Literal{text: self.to_string().into(), id: tt::TokenId::unspecified()}};
+    i32 => self { tt::Literal{text: self.to_string().into(), id: tt::TokenId::unspecified()}};
+    tt::Leaf => self { self };
+    tt::Literal => self { self };
+    tt::Ident => self { self };
+    tt::Punct => self { self };
+    &str => self { tt::Literal{text: format!("{:?}", self.escape_default().to_string()).into(), id: tt::TokenId::unspecified()}};
+    String => self { tt::Literal{text: format!("{:?}", self.escape_default().to_string()).into(), id: tt::TokenId::unspecified()}}
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_quote_delimiters() {
+        assert_eq!(quote!({}).to_string(), "{}");
+        assert_eq!(quote!(()).to_string(), "()");
+        assert_eq!(quote!([]).to_string(), "[]");
+    }
+
+    #[test]
+    fn test_quote_idents() {
+        assert_eq!(quote!(32).to_string(), "32");
+        assert_eq!(quote!(struct).to_string(), "struct");
+    }
+
+    #[test]
+    fn test_quote_hash_simple_literal() {
+        let a = 20;
+        assert_eq!(quote!(#a).to_string(), "20");
+        let s: String = "hello".into();
+        assert_eq!(quote!(#s).to_string(), "\"hello\"");
+    }
+
+    fn mk_ident(name: &str) -> tt::Ident {
+        tt::Ident { text: name.into(), id: tt::TokenId::unspecified() }
+    }
+
+    #[test]
+    fn test_quote_hash_token_tree() {
+        let a = mk_ident("hello");
+
+        let quoted = quote!(#a);
+        assert_eq!(quoted.to_string(), "hello");
+        let t = format!("{:?}", quoted);
+        assert_eq!(t, "SUBTREE $\n  IDENT   hello 4294967295");
+    }
+
+    #[test]
+    fn test_quote_simple_derive_copy() {
+        let name = mk_ident("Foo");
+
+        let quoted = quote! {
+            impl Clone for #name {
+                fn clone(&self) -> Self {
+                    Self {}
+                }
+            }
+        };
+
+        assert_eq!(quoted.to_string(), "impl Clone for Foo {fn clone (& self) -> Self {Self {}}}");
+    }
+
+    #[test]
+    fn test_quote_derive_copy_hack() {
+        // Assume the given struct is:
+        // struct Foo {
+        //  name: String,
+        //  id: u32,
+        // }
+        let struct_name = mk_ident("Foo");
+        let fields = [mk_ident("name"), mk_ident("id")];
+        let fields = fields.iter().map(|it| quote!(#it: self.#it.clone(), ).token_trees).flatten();
+
+        let list = tt::Subtree {
+            delimiter: Some(tt::Delimiter {
+                kind: tt::DelimiterKind::Brace,
+                id: tt::TokenId::unspecified(),
+            }),
+            token_trees: fields.collect(),
+        };
+
+        let quoted = quote! {
+            impl Clone for #struct_name {
+                fn clone(&self) -> Self {
+                    Self #list
+                }
+            }
+        };
+
+        assert_eq!(quoted.to_string(), "impl Clone for Foo {fn clone (& self) -> Self {Self {name : self . name . clone () , id : self . id . clone () ,}}}");
+    }
+}