use usual token tree for macro expansion

Author: matklad

crates/ra_mbe/src/lib.rs

@@ -3,26 +3,13 @@
 /// interface, although it contains some code to bridge `SyntaxNode`s and
 /// `TokenTree`s as well!
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident), *) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-        )*
-    }
-}
-
+mod parser;
 mod mbe_parser;
 mod mbe_expander;
 mod syntax_bridge;
-mod tt_cursor;
+mod tt_iter;
 mod subtree_source;
-mod subtree_parser;
 
-use ra_syntax::SmolStr;
 use smallvec::SmallVec;
 
 pub use tt::{Delimiter, Punct};
@@ -38,6 +25,7 @@ pub enum ExpandError {
     UnexpectedToken,
     BindingError(String),
     ConversionError,
+    InvalidRepeat,
 }
 
 pub use crate::syntax_bridge::{
@@ -65,31 +53,8 @@ impl MacroRules {
 
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub(crate) struct Rule {
-    pub(crate) lhs: Subtree,
-    pub(crate) rhs: Subtree,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) enum TokenTree {
-    Leaf(Leaf),
-    Subtree(Subtree),
-    Repeat(Repeat),
-}
-impl_froms!(TokenTree: Leaf, Subtree, Repeat);
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) enum Leaf {
-    Literal(Literal),
-    Punct(Punct),
-    Ident(Ident),
-    Var(Var),
-}
-impl_froms!(Leaf: Literal, Punct, Ident, Var);
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Subtree {
-    pub(crate) delimiter: Delimiter,
-    pub(crate) token_trees: Vec<TokenTree>,
+    pub(crate) lhs: tt::Subtree,
+    pub(crate) rhs: tt::Subtree,
 }
 
 #[derive(Clone, Debug, Eq)]
@@ -117,35 +82,5 @@ impl PartialEq for crate::Separator {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Repeat {
-    pub(crate) subtree: Subtree,
-    pub(crate) kind: RepeatKind,
-    pub(crate) separator: Option<Separator>,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) enum RepeatKind {
-    ZeroOrMore,
-    OneOrMore,
-    ZeroOrOne,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Literal {
-    pub(crate) text: SmolStr,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Ident {
-    pub(crate) text: SmolStr,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Var {
-    pub(crate) text: SmolStr,
-    pub(crate) kind: Option<SmolStr>,
-}
-
 #[cfg(test)]
 mod tests;

crates/ra_mbe/src/mbe_expander.rs

@@ -8,7 +8,6 @@ mod transcriber;
 use ra_syntax::SmolStr;
 use rustc_hash::FxHashMap;
 
-use crate::tt_cursor::TtCursor;
 use crate::ExpandError;
 
 pub(crate) fn expand(
@@ -19,12 +18,8 @@ pub(crate) fn expand(
 }
 
 fn expand_rule(rule: &crate::Rule, input: &tt::Subtree) -> Result<tt::Subtree, ExpandError> {
-    let mut input = TtCursor::new(input);
-    let bindings = matcher::match_lhs(&rule.lhs, &mut input)?;
-    if !input.is_eof() {
-        return Err(ExpandError::UnexpectedToken);
-    }
-    let res = transcriber::transcribe(&bindings, &rule.rhs)?;
+    let bindings = matcher::match_(&rule.lhs, input)?;
+    let res = transcriber::transcribe(&rule.rhs, &bindings)?;
     Ok(res)
 }
 
@@ -103,13 +98,6 @@ mod tests {
 
     #[test]
     fn test_expand_rule() {
-        // FIXME: The missing $var check should be in parsing phase
-        // assert_err(
-        //     "($i:ident) => ($j)",
-        //     "foo!{a}",
-        //     ExpandError::BindingError(String::from("could not find binding `j`")),
-        // );
-
         assert_err(
             "($($i:ident);*) => ($i)",
             "foo!{a}",
@@ -118,9 +106,6 @@ mod tests {
             )),
         );
 
-        assert_err("($i) => ($i)", "foo!{a}", ExpandError::UnexpectedToken);
-        assert_err("($i:) => ($i)", "foo!{a}", ExpandError::UnexpectedToken);
-
         // FIXME:
         // Add an err test case for ($($i:ident)) => ($())
     }