auto merge of #12412 : alexcrichton/rust/deriving-show, r=huonw

This commit removes deriving(ToStr) in favor of deriving(Show), migrating all impls of ToStr to fmt::Show.

Most of the details can be found in the first commit message.

Closes #12477

Author: bors

src/doc/tutorial.md

@@ -2519,7 +2519,7 @@ of type `ABC` can be randomly generated and converted to a string:
 #[deriving(Eq)]
 struct Circle { radius: f64 }
 
-#[deriving(Rand, ToStr)]
+#[deriving(Rand, Show)]
 enum ABC { A, B, C }
 ~~~
 

src/libcollections/btree.rs

@@ -18,7 +18,8 @@
 ///a length (the height of the tree), and lower and upper bounds on the
 ///number of elements that a given node can contain.
 
-use std::vec::OwnedVector;
+use std::fmt;
+use std::fmt::Show;
 
 #[allow(missing_doc)]
 pub struct BTree<K, V> {
@@ -106,11 +107,10 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for BTree<K, V> {
     }
 }
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for BTree<K, V> {
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for BTree<K, V> {
     ///Returns a string representation of the BTree
-    fn to_str(&self) -> ~str {
-        let ret = self.root.to_str();
-        ret
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.root.fmt(f)
     }
 }
 
@@ -235,15 +235,15 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for Node<K, V> {
     }
 }
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for Node<K, V> {
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for Node<K, V> {
     ///Returns a string representation of a Node.
     ///Will iterate over the Node and show "Key: x, value: y, child: () // "
     ///for all elements in the Node. "Child" only exists if the Node contains
     ///a branch.
-    fn to_str(&self) -> ~str {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            LeafNode(ref leaf) => leaf.to_str(),
-            BranchNode(ref branch) => branch.to_str()
+            LeafNode(ref leaf) => leaf.fmt(f),
+            BranchNode(ref branch) => branch.fmt(f),
         }
     }
 }
@@ -401,10 +401,14 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for Leaf<K, V> {
 }
 
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for Leaf<K, V> {
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for Leaf<K, V> {
     ///Returns a string representation of a Leaf.
-    fn to_str(&self) -> ~str {
-        self.elts.iter().map(|s| s.to_str()).to_owned_vec().connect(" // ")
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for (i, s) in self.elts.iter().enumerate() {
+            if i != 0 { try!(write!(f.buf, " // ")) }
+            try!(write!(f.buf, "{}", *s))
+        }
+        Ok(())
     }
 }
 
@@ -618,13 +622,14 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for Branch<K, V> {
     }
 }
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for Branch<K, V> {
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for Branch<K, V> {
     ///Returns a string representation of a Branch.
-    fn to_str(&self) -> ~str {
-        let mut ret = self.elts.iter().map(|s| s.to_str()).to_owned_vec().connect(" // ");
-        ret.push_str(" // ");
-        ret.push_str("rightmost child: ("+ self.rightmost_child.to_str() +") ");
-        ret
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for (i, s) in self.elts.iter().enumerate() {
+            if i != 0 { try!(write!(f.buf, " // ")) }
+            try!(write!(f.buf, "{}", *s))
+        }
+        write!(f.buf, " // rightmost child: ({}) ", *self.rightmost_child)
     }
 }
 
@@ -672,11 +677,10 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for LeafElt<K, V> {
     }
 }
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for LeafElt<K, V> {
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for LeafElt<K, V> {
     ///Returns a string representation of a LeafElt.
-    fn to_str(&self) -> ~str {
-        format!("Key: {}, value: {};",
-            self.key.to_str(), self.value.to_str())
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f.buf, "Key: {}, value: {};", self.key, self.value)
     }
 }
 
@@ -715,12 +719,12 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for BranchElt<K, V> {
     }
 }
 
-impl<K: ToStr + TotalOrd, V: ToStr> ToStr for BranchElt<K, V> {
-    ///Returns string containing key, value, and child (which should recur to a leaf)
-    ///Consider changing in future to be more readable.
-    fn to_str(&self) -> ~str {
-        format!("Key: {}, value: {}, (child: {})",
-            self.key.to_str(), self.value.to_str(), self.left.to_str())
+impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for BranchElt<K, V> {
+    /// Returns string containing key, value, and child (which should recur to a
+    /// leaf) Consider changing in future to be more readable.
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f.buf, "Key: {}, value: {}, (child: {})",
+               self.key, self.value, *self.left)
     }
 }
 

src/libcollections/enum_set.rs

@@ -15,7 +15,7 @@
 
 use std::num::Bitwise;
 
-#[deriving(Clone, Eq, Hash, ToStr, Encodable, Decodable)]
+#[deriving(Clone, Eq, Hash, Show, Encodable, Decodable)]
 /// A specialized Set implementation to use enum types.
 pub struct EnumSet<E> {
     // We must maintain the invariant that no bits are set

src/libcollections/hashmap.rs

@@ -606,10 +606,6 @@ impl<A: fmt::Show + Hash + Eq, B: fmt::Show> fmt::Show for HashMap<A, B> {
     }
 }
 
-impl<K: fmt::Show + Hash + Eq, V: fmt::Show> ToStr for HashMap<K, V> {
-    fn to_str(&self) -> ~str { format!("{}", *self) }
-}
-
 /// HashMap iterator
 #[deriving(Clone)]
 pub struct Entries<'a, K, V> {
@@ -888,10 +884,6 @@ impl<A: fmt::Show + Hash + Eq> fmt::Show for HashSet<A> {
     }
 }
 
-impl<A: fmt::Show + Hash + Eq> ToStr for HashSet<A> {
-    fn to_str(&self) -> ~str { format!("{}", *self) }
-}
-
 impl<K: Eq + Hash> FromIterator<K> for HashSet<K> {
     fn from_iterator<T: Iterator<K>>(iter: &mut T) -> HashSet<K> {
         let (lower, _) = iter.size_hint();

src/libcollections/lru_cache.rs

@@ -37,10 +37,11 @@
 //! assert!(cache.get(&2).is_none());
 //! ```
 
+use std::cast;
 use std::container::Container;
 use std::hash::{Hash, sip};
+use std::fmt;
 use std::ptr;
-use std::cast;
 
 use HashMap;
 
@@ -217,36 +218,32 @@ impl<K: Hash + Eq, V> LruCache<K, V> {
     }
 }
 
-impl<A: ToStr + Hash + Eq, B: ToStr> ToStr for LruCache<A, B> {
+impl<A: fmt::Show + Hash + Eq, B: fmt::Show> fmt::Show for LruCache<A, B> {
     /// Return a string that lists the key-value pairs from most-recently
     /// used to least-recently used.
-    #[inline]
-    fn to_str(&self) -> ~str {
-        let mut acc = ~"{";
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        try!(write!(f.buf, r"\{"));
         let mut cur = self.head;
         for i in range(0, self.len()) {
-            if i > 0 {
-                acc.push_str(", ");
-            }
+            if i > 0 { try!(write!(f.buf, ", ")) }
             unsafe {
                 cur = (*cur).next;
                 match (*cur).key {
                     // should never print nil
-                    None => acc.push_str("nil"),
-                    Some(ref k) => acc.push_str(k.to_str())
+                    None => try!(write!(f.buf, "nil")),
+                    Some(ref k) => try!(write!(f.buf, "{}", *k)),
                 }
             }
-            acc.push_str(": ");
+            try!(write!(f.buf, ": "));
             unsafe {
                 match (*cur).value {
                     // should never print nil
-                    None => acc.push_str("nil"),
-                    Some(ref value) => acc.push_str(value.to_str())
+                    None => try!(write!(f.buf, "nil")),
+                    Some(ref value) => try!(write!(f.buf, "{}", *value)),
                 }
             }
         }
-        acc.push_char('}');
-        acc
+        write!(f.buf, r"\}")
     }
 }
 

src/libextra/json.rs

@@ -240,7 +240,7 @@ use std::io;
 use std::io::MemWriter;
 use std::num;
 use std::str;
-use std::to_str;
+use std::fmt;
 
 use serialize::Encodable;
 use serialize;
@@ -1576,18 +1576,16 @@ impl<A:ToJson> ToJson for Option<A> {
     }
 }
 
-impl to_str::ToStr for Json {
+impl fmt::Show for Json {
     /// Encodes a json value into a string
-    fn to_str(&self) -> ~str {
-        let mut s = MemWriter::new();
-        self.to_writer(&mut s as &mut io::Writer).unwrap();
-        str::from_utf8_owned(s.unwrap()).unwrap()
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.to_writer(f.buf)
     }
 }
 
-impl to_str::ToStr for Error {
-    fn to_str(&self) -> ~str {
-        format!("{}:{}: {}", self.line, self.col, self.msg)
+impl fmt::Show for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f.buf, "{}:{}: {}", self.line, self.col, self.msg)
     }
 }