X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=crates%2Ftt%2Fsrc%2Flib.rs;h=b2841370ec59d9b676622959ee58010964e90f91;hb=f1222e80850dca050e4f9a150514aeab9b27ac08;hp=20c3f5eabfb8dfe54e2e6e75ff3f51882239c737;hpb=550d7fbe3cbf2af4a47fca6c9bbefaf798cd7b7b;p=rust.git

diff --git a/crates/tt/src/lib.rs b/crates/tt/src/lib.rs
index 20c3f5eabfb..b2841370ec5 100644
--- a/crates/tt/src/lib.rs
+++ b/crates/tt/src/lib.rs
@@ -1,10 +1,7 @@
 //! `tt` crate defines a `TokenTree` data structure: this is the interface (both
 //! input and output) of macros. It closely mirrors `proc_macro` crate's
 //! `TokenTree`.
-use std::{
-    fmt::{self, Debug},
-    panic::RefUnwindSafe,
-};
+use std::fmt;
 
 use stdx::impl_from;
 
@@ -91,7 +88,7 @@ pub struct Ident {
 }
 
 fn print_debug_subtree(f: &mut fmt::Formatter<'_>, subtree: &Subtree, level: usize) -> fmt::Result {
-    let align = std::iter::repeat("  ").take(level).collect::<String>();
+    let align = "  ".repeat(level);
 
     let aux = match subtree.delimiter.map(|it| (it.kind, it.id.0)) {
         None => "$".to_string(),
@@ -116,7 +113,7 @@ fn print_debug_subtree(f: &mut fmt::Formatter<'_>, subtree: &Subtree, level: usi
 }
 
 fn print_debug_token(f: &mut fmt::Formatter<'_>, tkn: &TokenTree, level: usize) -> fmt::Result {
-    let align = std::iter::repeat("  ").take(level).collect::<String>();
+    let align = "  ".repeat(level);
 
     match tkn {
         TokenTree::Leaf(leaf) => match leaf {
@@ -139,7 +136,7 @@ fn print_debug_token(f: &mut fmt::Formatter<'_>, tkn: &TokenTree, level: usize)
     Ok(())
 }
 
-impl Debug for Subtree {
+impl fmt::Debug for Subtree {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         print_debug_subtree(f, self, 0)
     }
@@ -230,17 +227,65 @@ pub fn delimiter_kind(&self) -> Option<DelimiterKind> {
     }
 }
 
+impl Subtree {
+    /// A simple line string used for debugging
+    pub fn as_debug_string(&self) -> String {
+        let delim = match self.delimiter_kind() {
+            Some(DelimiterKind::Brace) => ("{", "}"),
+            Some(DelimiterKind::Bracket) => ("[", "]"),
+            Some(DelimiterKind::Parenthesis) => ("(", ")"),
+            None => (" ", " "),
+        };
+
+        let mut res = String::new();
+        res.push_str(delim.0);
+        let mut last = None;
+        for child in &self.token_trees {
+            let s = match child {
+                TokenTree::Leaf(it) => {
+                    let s = match it {
+                        Leaf::Literal(it) => it.text.to_string(),
+                        Leaf::Punct(it) => it.char.to_string(),
+                        Leaf::Ident(it) => it.text.to_string(),
+                    };
+                    match (it, last) {
+                        (Leaf::Ident(_), Some(&TokenTree::Leaf(Leaf::Ident(_)))) => {
+                            " ".to_string() + &s
+                        }
+                        (Leaf::Punct(_), Some(&TokenTree::Leaf(Leaf::Punct(punct)))) => {
+                            if punct.spacing == Spacing::Alone {
+                                " ".to_string() + &s
+                            } else {
+                                s
+                            }
+                        }
+                        _ => s,
+                    }
+                }
+                TokenTree::Subtree(it) => it.as_debug_string(),
+            };
+            res.push_str(&s);
+            last = Some(child);
+        }
+
+        res.push_str(delim.1);
+        res
+    }
+}
+
 pub mod buffer;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum ExpansionError {
-    IOError(String),
-    JsonError(String),
     Unknown(String),
     ExpansionError(String),
 }
 
-pub trait TokenExpander: Debug + Send + Sync + RefUnwindSafe {
-    fn expand(&self, subtree: &Subtree, attrs: Option<&Subtree>)
-        -> Result<Subtree, ExpansionError>;
+impl fmt::Display for ExpansionError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ExpansionError::Unknown(e) => e.fmt(f),
+            ExpansionError::ExpansionError(e) => write!(f, "proc macro returned error: {}", e),
+        }
+    }
 }