1 files changed, 131 insertions, 0 deletions

diff --git a/crates/ra_tt/src/lib.rs b/crates/ra_tt/src/lib.rs
new file mode 100644
index 000000000..d7c3c62bf
--- /dev/null
+++ b/crates/ra_tt/src/lib.rs
@@ -0,0 +1,131 @@
+macro_rules! impl_froms {
+    ($e:ident: $($v:ident), *) => {
+        $(
+            impl From<$v> for $e {
+                fn from(it: $v) -> $e {
+                    $e::$v(it)
+                }
+            }
+        )*
+    }
+}
+
+use std::fmt;
+
+use smol_str::SmolStr;
+
+#[derive(Debug, Clone)]
+pub enum TokenTree {
+    Leaf(Leaf),
+    Subtree(Subtree),
+}
+impl_froms!(TokenTree: Leaf, Subtree);
+
+#[derive(Debug, Clone)]
+pub enum Leaf {
+    Literal(Literal),
+    Punct(Punct),
+    Ident(Ident),
+}
+impl_froms!(Leaf: Literal, Punct, Ident);
+
+#[derive(Debug, Clone)]
+pub struct Subtree {
+    pub delimiter: Delimiter,
+    pub token_trees: Vec<TokenTree>,
+}
+
+#[derive(Clone, Copy, Debug)]
+pub enum Delimiter {
+    Parenthesis,
+    Brace,
+    Bracket,
+    None,
+}
+
+#[derive(Debug, Clone)]
+pub struct Literal {
+    pub text: SmolStr,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Punct {
+    pub char: char,
+    pub spacing: Spacing,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Spacing {
+    Alone,
+    Joint,
+}
+
+#[derive(Debug, Clone)]
+pub struct Ident {
+    pub text: SmolStr,
+}
+
+impl fmt::Display for TokenTree {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            TokenTree::Leaf(it) => fmt::Display::fmt(it, f),
+            TokenTree::Subtree(it) => fmt::Display::fmt(it, f),
+        }
+    }
+}
+
+impl fmt::Display for Subtree {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let (l, r) = match self.delimiter {
+            Delimiter::Parenthesis => ("(", ")"),
+            Delimiter::Brace => ("{", "}"),
+            Delimiter::Bracket => ("[", "]"),
+            Delimiter::None => ("", ""),
+        };
+        f.write_str(l)?;
+        let mut needs_space = false;
+        for tt in self.token_trees.iter() {
+            if needs_space {
+                f.write_str(" ")?;
+            }
+            needs_space = true;
+            match tt {
+                TokenTree::Leaf(Leaf::Punct(p)) => {
+                    needs_space = p.spacing == Spacing::Alone;
+                    fmt::Display::fmt(p, f)?
+                }
+                tt => fmt::Display::fmt(tt, f)?,
+            }
+        }
+        f.write_str(r)?;
+        Ok(())
+    }
+}
+
+impl fmt::Display for Leaf {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Leaf::Ident(it) => fmt::Display::fmt(it, f),
+            Leaf::Literal(it) => fmt::Display::fmt(it, f),
+            Leaf::Punct(it) => fmt::Display::fmt(it, f),
+        }
+    }
+}
+
+impl fmt::Display for Ident {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.text, f)
+    }
+}
+
+impl fmt::Display for Literal {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.text, f)
+    }
+}
+
+impl fmt::Display for Punct {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.char, f)
+    }
+}