From 2c4b6d6f7d6001bf9241f90f1465f4a98490a0d9 Mon Sep 17 00:00:00 2001
From: John Clements <clements@racket-lang.org>
Date: Thu, 10 Jul 2014 17:46:09 -0700
Subject: [PATCH] add make_method method to MacResult trait

this allows macro results to be parsed as methods
---
 src/libsyntax/ext/base.rs           | 18 ++++++++++++++++++
 src/libsyntax/ext/tt/macro_rules.rs | 19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index dcb69ae8f7e64..56484c4ba59df 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -104,6 +104,9 @@ pub type IdentMacroExpanderFn =
 /// just into the compiler's internal macro table, for `make_def`).
 pub trait MacResult {
     /// Define a new macro.
+    // this should go away; the idea that a macro might expand into
+    // either a macro definition or an expression, depending on what
+    // the context wants, is kind of silly.
     fn make_def(&self) -> Option<MacroDef> {
         None
     }
@@ -115,6 +118,12 @@ pub trait MacResult {
     fn make_items(&self) -> Option<SmallVector<Gc<ast::Item>>> {
         None
     }
+
+    /// Create zero or more methods.
+    fn make_methods(&self) -> Option<SmallVector<Gc<ast::Method>>> {
+        None
+    }
+
     /// Create a pattern.
     fn make_pat(&self) -> Option<Gc<ast::Pat>> {
         None
@@ -222,6 +231,7 @@ impl DummyResult {
             span: sp,
         }
     }
+
 }
 
 impl MacResult for DummyResult {
@@ -232,6 +242,14 @@ impl MacResult for DummyResult {
         Some(DummyResult::raw_pat(self.span))
     }
     fn make_items(&self) -> Option<SmallVector<Gc<ast::Item>>> {
+        // this code needs a comment... why not always just return the Some() ?
+        if self.expr_only {
+            None
+        } else {
+            Some(SmallVector::zero())
+        }
+    }
+    fn make_methods(&self) -> Option<SmallVector<Gc<ast::Method>>> {
         if self.expr_only {
             None
         } else {
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 923b3e78731a0..1eb37abb781a3 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -38,7 +38,7 @@ struct ParserAnyMacro<'a> {
 impl<'a> ParserAnyMacro<'a> {
     /// Make sure we don't have any tokens left to parse, so we don't
     /// silently drop anything. `allow_semi` is so that "optional"
-    /// semilons at the end of normal expressions aren't complained
+    /// semicolons at the end of normal expressions aren't complained
     /// about e.g. the semicolon in `macro_rules! kapow( () => {
     /// fail!(); } )` doesn't get picked up by .parse_expr(), but it's
     /// allowed to be there.
@@ -73,6 +73,9 @@ impl<'a> MacResult for ParserAnyMacro<'a> {
         let mut ret = SmallVector::zero();
         loop {
             let mut parser = self.parser.borrow_mut();
+            // so... do outer attributes attached to the macro invocation
+            // just disappear? This question applies to make_methods, as
+            // well.
             match parser.parse_item_with_outer_attributes() {
                 Some(item) => ret.push(item),
                 None => break
@@ -81,6 +84,20 @@ impl<'a> MacResult for ParserAnyMacro<'a> {
         self.ensure_complete_parse(false);
         Some(ret)
     }
+
+    fn make_methods(&self) -> Option<SmallVector<Gc<ast::Method>>> {
+        let mut ret = SmallVector::zero();
+        loop {
+            let mut parser = self.parser.borrow_mut();
+            match parser.token {
+                EOF => break,
+                _ => ret.push(parser.parse_method(None))
+            }
+        }
+        self.ensure_complete_parse(false);
+        Some(ret)
+    }
+
     fn make_stmt(&self) -> Option<Gc<ast::Stmt>> {
         let attrs = self.parser.borrow_mut().parse_outer_attributes();
         let ret = self.parser.borrow_mut().parse_stmt(attrs);