X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=crates%2Fmbe%2Fsrc%2Flib.rs;h=6402ceadaaae6d824e29bf2a95c344ae86fd3a4f;hb=0b53744f2d7e0694cd7207cca632fd6de1dc5bff;hp=8d223c375a33284d5fabe1b269a2423026c5b1f2;hpb=40009e07d002bf676b4b32e90a858aed37ea4cc2;p=rust.git

diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index 8d223c375a3..6402ceadaaa 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -30,19 +30,30 @@
 pub use crate::{
     syntax_bridge::{
         parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
-        syntax_node_to_token_tree_censored, token_tree_to_syntax_node,
+        syntax_node_to_token_tree_with_modifications, token_tree_to_syntax_node, SyntheticToken,
+        SyntheticTokenId,
     },
     token_map::TokenMap,
 };
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum ParseError {
-    UnexpectedToken(String),
-    Expected(String),
+    UnexpectedToken(Box<str>),
+    Expected(Box<str>),
     InvalidRepeat,
     RepetitionEmptyTokenTree,
 }
 
+impl ParseError {
+    fn expected(e: &str) -> ParseError {
+        ParseError::Expected(e.into())
+    }
+
+    fn unexpected(e: &str) -> ParseError {
+        ParseError::UnexpectedToken(e.into())
+    }
+}
+
 impl fmt::Display for ParseError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
@@ -56,13 +67,18 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum ExpandError {
+    BindingError(Box<Box<str>>),
+    LeftoverTokens,
+    ConversionError,
+    LimitExceeded,
     NoMatchingRule,
     UnexpectedToken,
-    BindingError(String),
-    ConversionError,
-    // FIXME: no way mbe should know about proc macros.
-    UnresolvedProcMacro,
-    Other(String),
+}
+
+impl ExpandError {
+    fn binding_error(e: impl Into<Box<str>>) -> ExpandError {
+        ExpandError::BindingError(Box::new(e.into()))
+    }
 }
 
 impl fmt::Display for ExpandError {
@@ -72,8 +88,8 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
             ExpandError::UnexpectedToken => f.write_str("unexpected token in input"),
             ExpandError::BindingError(e) => f.write_str(e),
             ExpandError::ConversionError => f.write_str("could not convert tokens"),
-            ExpandError::UnresolvedProcMacro => f.write_str("unresolved proc macro"),
-            ExpandError::Other(e) => f.write_str(e),
+            ExpandError::LimitExceeded => f.write_str("Expand exceed limit"),
+            ExpandError::LeftoverTokens => f.write_str("leftover tokens"),
         }
     }
 }
@@ -107,28 +123,25 @@ pub fn new(tt: &tt::Subtree) -> Shift {
 
         // Find the max token id inside a subtree
         fn max_id(subtree: &tt::Subtree) -> Option<u32> {
-            subtree
-                .token_trees
-                .iter()
-                .filter_map(|tt| match tt {
-                    tt::TokenTree::Subtree(subtree) => {
-                        let tree_id = max_id(subtree);
-                        match subtree.delimiter {
-                            Some(it) if it.id != tt::TokenId::unspecified() => {
-                                Some(tree_id.map_or(it.id.0, |t| t.max(it.id.0)))
-                            }
-                            _ => tree_id,
+            let filter = |tt: &_| match tt {
+                tt::TokenTree::Subtree(subtree) => {
+                    let tree_id = max_id(subtree);
+                    match subtree.delimiter {
+                        Some(it) if it.id != tt::TokenId::unspecified() => {
+                            Some(tree_id.map_or(it.id.0, |t| t.max(it.id.0)))
                         }
+                        _ => tree_id,
                     }
-                    tt::TokenTree::Leaf(leaf) => {
-                        let &(tt::Leaf::Ident(tt::Ident { id, .. })
-                        | tt::Leaf::Punct(tt::Punct { id, .. })
-                        | tt::Leaf::Literal(tt::Literal { id, .. })) = leaf;
+                }
+                tt::TokenTree::Leaf(leaf) => {
+                    let &(tt::Leaf::Ident(tt::Ident { id, .. })
+                    | tt::Leaf::Punct(tt::Punct { id, .. })
+                    | tt::Leaf::Literal(tt::Literal { id, .. })) = leaf;
 
-                        (id != tt::TokenId::unspecified()).then(|| id.0)
-                    }
-                })
-                .max()
+                    (id != tt::TokenId::unspecified()).then(|| id.0)
+                }
+            };
+            subtree.token_trees.iter().filter_map(filter).max()
         }
     }
 
@@ -183,7 +196,7 @@ pub fn parse_macro_rules(tt: &tt::Subtree) -> Result<DeclarativeMacro, ParseErro
             rules.push(rule);
             if let Err(()) = src.expect_char(';') {
                 if src.len() > 0 {
-                    return Err(ParseError::Expected("expected `;`".to_string()));
+                    return Err(ParseError::expected("expected `;`"));
                 }
                 break;
             }
@@ -208,9 +221,7 @@ pub fn parse_macro2(tt: &tt::Subtree) -> Result<DeclarativeMacro, ParseError> {
                 rules.push(rule);
                 if let Err(()) = src.expect_any_char(&[';', ',']) {
                     if src.len() > 0 {
-                        return Err(ParseError::Expected(
-                            "expected `;` or `,` to delimit rules".to_string(),
-                        ));
+                        return Err(ParseError::expected("expected `;` or `,` to delimit rules"));
                     }
                     break;
                 }
@@ -219,7 +230,7 @@ pub fn parse_macro2(tt: &tt::Subtree) -> Result<DeclarativeMacro, ParseError> {
             cov_mark::hit!(parse_macro_def_simple);
             let rule = Rule::parse(&mut src, false)?;
             if src.len() != 0 {
-                return Err(ParseError::Expected("remaining tokens in macro def".to_string()));
+                return Err(ParseError::expected("remaining tokens in macro def"));
             }
             rules.push(rule);
         }
@@ -256,16 +267,12 @@ pub fn shift(&self) -> Shift {
 
 impl Rule {
     fn parse(src: &mut TtIter, expect_arrow: bool) -> Result<Self, ParseError> {
-        let lhs = src
-            .expect_subtree()
-            .map_err(|()| ParseError::Expected("expected subtree".to_string()))?;
+        let lhs = src.expect_subtree().map_err(|()| ParseError::expected("expected subtree"))?;
         if expect_arrow {
-            src.expect_char('=').map_err(|()| ParseError::Expected("expected `=`".to_string()))?;
-            src.expect_char('>').map_err(|()| ParseError::Expected("expected `>`".to_string()))?;
+            src.expect_char('=').map_err(|()| ParseError::expected("expected `=`"))?;
+            src.expect_char('>').map_err(|()| ParseError::expected("expected `>`"))?;
         }
-        let rhs = src
-            .expect_subtree()
-            .map_err(|()| ParseError::Expected("expected subtree".to_string()))?;
+        let rhs = src.expect_subtree().map_err(|()| ParseError::expected("expected subtree"))?;
 
         let lhs = MetaTemplate::parse_pattern(lhs)?;
         let rhs = MetaTemplate::parse_template(rhs)?;
@@ -303,42 +310,41 @@ fn validate(pattern: &MetaTemplate) -> Result<(), ParseError> {
     Ok(())
 }
 
+pub type ExpandResult<T> = ValueResult<T, ExpandError>;
+
 #[derive(Debug, Clone, Eq, PartialEq)]
-pub struct ExpandResult<T> {
+pub struct ValueResult<T, E> {
     pub value: T,
-    pub err: Option<ExpandError>,
+    pub err: Option<E>,
 }
 
-impl<T> ExpandResult<T> {
+impl<T, E> ValueResult<T, E> {
     pub fn ok(value: T) -> Self {
         Self { value, err: None }
     }
 
-    pub fn only_err(err: ExpandError) -> Self
+    pub fn only_err(err: E) -> Self
     where
         T: Default,
     {
         Self { value: Default::default(), err: Some(err) }
     }
 
-    pub fn str_err(err: String) -> Self
-    where
-        T: Default,
-    {
-        Self::only_err(ExpandError::Other(err))
+    pub fn map<U>(self, f: impl FnOnce(T) -> U) -> ValueResult<U, E> {
+        ValueResult { value: f(self.value), err: self.err }
     }
 
-    pub fn map<U>(self, f: impl FnOnce(T) -> U) -> ExpandResult<U> {
-        ExpandResult { value: f(self.value), err: self.err }
+    pub fn map_err<E2>(self, f: impl FnOnce(E) -> E2) -> ValueResult<T, E2> {
+        ValueResult { value: self.value, err: self.err.map(f) }
     }
 
-    pub fn result(self) -> Result<T, ExpandError> {
+    pub fn result(self) -> Result<T, E> {
         self.err.map_or(Ok(self.value), Err)
     }
 }
 
-impl<T: Default> From<Result<T, ExpandError>> for ExpandResult<T> {
-    fn from(result: Result<T, ExpandError>) -> Self {
+impl<T: Default, E> From<Result<T, E>> for ValueResult<T, E> {
+    fn from(result: Result<T, E>) -> Self {
         result.map_or_else(Self::only_err, Self::ok)
     }
 }