Support meaningful spans in the stable version of proc-macro2

.travis.yml

@@ -12,12 +12,15 @@ matrix:
       script:
         - cargo test
         - cargo build --features unstable
-        - cargo doc --no-deps
+        - RUSTFLAGS='--cfg procmacro2_unstable' cargo test
+        - RUSTFLAGS='--cfg procmacro2_unstable' cargo build --features unstable
+        - RUSTFLAGS='--cfg procmacro2_unstable' cargo doc --no-deps
       after_success:
         - travis-cargo --only nightly doc-upload
 
 script:
   - cargo test
+  - RUSTFLAGS='--cfg procmacro2_unstable' cargo test
 env:
   global:
     - TRAVIS_CARGO_NIGHTLY_FEATURE=""

README.md

@@ -59,6 +59,17 @@ proc-macro2 = { version = "0.1", features = ["unstable"] }
 ```
 
 
+## Unstable Features
+
+`proc-macro2` supports exporting some methods from `proc_macro` which are
+currently highly unstable, and may not be stabilized in the first pass of
+`proc_macro` stabilizations. These features are not exported by default.
+
+To export these features, the `procmacro2_unstable` config flag must be passed
+to rustc. To pass this flag, run `cargo` with 
+`RUSTFLAGS='--cfg procmacro2_unstable' cargo build`.
+
+
 # License
 
 This project is licensed under either of

src/lib.rs

@@ -103,6 +103,46 @@ impl TokenStream {
     }
 }
 
+// Returned by reference, so we can't easily wrap it.
+#[cfg(procmacro2_unstable)]
+pub use imp::FileName;
+
+#[cfg(procmacro2_unstable)]
+#[derive(Clone, PartialEq, Eq)]
+pub struct SourceFile(imp::SourceFile);
+
+#[cfg(procmacro2_unstable)]
+impl SourceFile {
+    /// Get the path to this source file as a string.
+    pub fn path(&self) -> &FileName {
+        self.0.path()
+    }
+
+    pub fn is_real(&self) -> bool {
+        self.0.is_real()
+    }
+}
+
+#[cfg(procmacro2_unstable)]
+impl AsRef<FileName> for SourceFile {
+    fn as_ref(&self) -> &FileName {
+        self.0.path()
+    }
+}
+
+#[cfg(procmacro2_unstable)]
+impl fmt::Debug for SourceFile {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+#[cfg(procmacro2_unstable)]
+pub struct LineColumn {
+    pub line: usize,
+    pub column: usize,
+}
+
 #[derive(Copy, Clone)]
 pub struct Span(imp::Span);
 
@@ -121,6 +161,28 @@ impl Span {
     pub fn def_site() -> Span {
         Span(imp::Span::def_site())
     }
+
+    #[cfg(procmacro2_unstable)]
+    pub fn source_file(&self) -> SourceFile {
+        SourceFile(self.0.source_file())
+    }
+
+    #[cfg(procmacro2_unstable)]
+    pub fn start(&self) -> LineColumn {
+        let imp::LineColumn{ line, column } = self.0.start();
+        LineColumn { line, column }
+    }
+
+    #[cfg(procmacro2_unstable)]
+    pub fn end(&self) -> LineColumn {
+        let imp::LineColumn{ line, column } = self.0.end();
+        LineColumn { line, column }
+    }
+
+    #[cfg(procmacro2_unstable)]
+    pub fn join(&self, other: Span) -> Option<Span> {
+        self.0.join(other.0).map(Span)
+    }
 }
 
 #[derive(Clone, Debug)]