commit e0824038665c8f04dc677e906fa220426d356d6f
author David Tolnay <dtolnay@gmail.com> Wed Dec 27 15:25:56 2017 -0500
committer David Tolnay <dtolnay@gmail.com> Wed Dec 27 15:26:12 2017 -0500
tree 7330de4b92b20331724ee11ba871dc50cefbc25f
parent 4699a31b77645230ce2e0bc8c7666cb8806180c8

Restrict grammer of 2.0 macros

The arguments must be parenthesized and the body must be braced.

src/item.rs

diff --git a/src/item.rs b/src/item.rs
index 7fd97a3..7d0728c 100644
--- a/src/item.rs
+++ b/src/item.rs
@@ -514,7 +514,7 @@
         what: syn!(Path) >>
         bang: punct!(!) >>
         ident: option!(syn!(Ident)) >>
-        body: call!(mac::parsing::parse_tt_delimited) >>
+        body: call!(tt::delimited) >>
         cond!(!mac::is_braced(&body), punct!(;)) >>
         (ItemMacro {
             attrs: attrs,
@@ -533,8 +533,8 @@
         vis: syn!(Visibility) >>
         macro_: keyword!(macro) >>
         ident: syn!(Ident) >>
-        args: call!(mac::parsing::parse_tt_delimited) >>
-        body: call!(mac::parsing::parse_tt_delimited) >>
+        args: call!(tt::parenthesized) >>
+        body: call!(tt::braced) >>
         (ItemMacro2 {
             attrs: attrs,
             vis: vis,

src/lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index 106a045..edfea5c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -101,6 +101,8 @@
 #[cfg(feature = "parsing")]
 pub mod synom;
 pub mod delimited;
+#[cfg(feature = "parsing")]
+mod tt;
 
 mod gen {
     #[cfg(feature = "visit")]

src/mac.rs

diff --git a/src/mac.rs b/src/mac.rs
index f093a8c..2316506 100644
--- a/src/mac.rs
+++ b/src/mac.rs
@@ -170,16 +170,13 @@
 pub mod parsing {
     use super::*;
 
-    use proc_macro2::{TokenNode, TokenTree};
     use synom::Synom;
-    use cursor::Cursor;
-    use {parse_error, PResult};
 
     impl Synom for Macro {
         named!(parse -> Self, do_parse!(
             what: syn!(Path) >>
             bang: punct!(!) >>
-            body: call!(parse_tt_delimited) >>
+            body: call!(tt::delimited) >>
             (Macro {
                 path: what,
                 bang_token: bang,
@@ -187,19 +184,6 @@
             })
         ));
     }
-
-    pub fn parse_tt_delimited(input: Cursor) -> PResult<TokenTree> {
-        match input.token_tree() {
-            Some((
-                rest,
-                token @ TokenTree {
-                    kind: TokenNode::Group(..),
-                    ..
-                },
-            )) => Ok((rest, token)),
-            _ => parse_error(),
-        }
-    }
 }
 
 #[cfg(feature = "printing")]

src/tt.rs

diff --git a/src/tt.rs b/src/tt.rs
new file mode 100644
index 0000000..8a7f0e5
--- /dev/null
+++ b/src/tt.rs
@@ -0,0 +1,47 @@
+use proc_macro2::{TokenNode, TokenTree};
+use cursor::Cursor;
+use {parse_error, PResult};
+
+#[cfg(feature = "full")]
+use proc_macro2::Delimiter;
+
+pub fn delimited(input: Cursor) -> PResult<TokenTree> {
+    match input.token_tree() {
+        Some((
+            rest,
+            token @ TokenTree {
+                kind: TokenNode::Group(..),
+                ..
+            },
+        )) => Ok((rest, token)),
+        _ => parse_error(),
+    }
+}
+
+#[cfg(feature = "full")]
+pub fn braced(input: Cursor) -> PResult<TokenTree> {
+    match input.token_tree() {
+        Some((
+            rest,
+            token @ TokenTree {
+                kind: TokenNode::Group(Delimiter::Brace, ..),
+                ..
+            },
+        )) => Ok((rest, token)),
+        _ => parse_error(),
+    }
+}
+
+#[cfg(feature = "full")]
+pub fn parenthesized(input: Cursor) -> PResult<TokenTree> {
+    match input.token_tree() {
+        Some((
+            rest,
+            token @ TokenTree {
+                kind: TokenNode::Group(Delimiter::Parenthesis, ..),
+                ..
+            },
+        )) => Ok((rest, token)),
+        _ => parse_error(),
+    }
+}