Build a few extra features into format! parsing

* Allow named parameters to specify width/precision
* Intepret the format string '0$' as "width is the 0th argument" instead of
  thinking the lone '0' was the sign-aware-zero-padding flag. To get both you'd
  need to put '00$' which makes more sense if you want both to happen.

Closes #9669

1 files changed, 15 insertions, 0 deletions

diff --git a/src/libstd/fmt/rt.rs b/src/libstd/fmt/rt.rs
index 90763836fc6..063d712dfa9 100644
--- a/src/libstd/fmt/rt.rs
+++ b/src/libstd/fmt/rt.rs
@@ -34,6 +34,7 @@ pub struct Argument<'self> {
     method: Option<&'self Method<'self>>
 }
 
+#[cfg(stage0)]
 pub struct FormatSpec {
     fill: char,
     align: parse::Alignment,
@@ -42,6 +43,20 @@ pub struct FormatSpec {
     width: parse::Count,
 }
 
+#[cfg(not(stage0))]
+pub struct FormatSpec {
+    fill: char,
+    align: parse::Alignment,
+    flags: uint,
+    precision: Count,
+    width: Count,
+}
+
+#[cfg(not(stage0))]
+pub enum Count {
+    CountIs(uint), CountIsParam(uint), CountIsNextParam, CountImplied,
+}
+
 pub enum Position {
     ArgumentNext, ArgumentIs(uint)
 }