---

yaml
---
r: 140906
b: refs/heads/try2
c: 918bfa7
h: refs/heads/master
v: v3

Author: bors

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: c2baaa8d8432c8d7320e928e7ad706f225430bb3
+refs/heads/try2: 918bfa710c2079ed1a690036eb794694b75faa30
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libcore/iter.rs

@@ -43,6 +43,8 @@ much easier to implement.
 #[cfg(not(stage0))] use cmp::Ord;
 #[cfg(not(stage0))] use option::{Option, Some, None};
 #[cfg(not(stage0))] use vec::OwnedVector;
+#[cfg(not(stage0))] use num::{One, Zero};
+#[cfg(not(stage0))] use ops::{Add, Mul};
 
 #[cfg(stage0)]
 pub trait Times {
@@ -212,6 +214,81 @@ pub fn min<T: Ord>(iter: &fn(f: &fn(T) -> bool) -> bool) -> Option<T> {
     result
 }
 
+/**
+ * Reduce an iterator to an accumulated value.
+ *
+ * # Example:
+ *
+ * ~~~~
+ * assert_eq!(fold(0i, |f| int::range(1, 5, f), |a, x| *a += x), 10);
+ * ~~~~
+ */
+#[cfg(not(stage0))]
+#[inline]
+pub fn fold<T, U>(start: T, iter: &fn(f: &fn(U) -> bool) -> bool, f: &fn(&mut T, U)) -> T {
+    let mut result = start;
+    for iter |x| {
+        f(&mut result, x);
+    }
+    result
+}
+
+/**
+ * Reduce an iterator to an accumulated value.
+ *
+ * `fold_ref` is usable in some generic functions where `fold` is too lenient to type-check, but it
+ * forces the iterator to yield borrowed pointers.
+ *
+ * # Example:
+ *
+ * ~~~~
+ * fn product<T: One + Mul<T, T>>(iter: &fn(f: &fn(&T) -> bool) -> bool) -> T {
+ *     fold_ref(One::one::<T>(), iter, |a, x| *a = a.mul(x))
+ * }
+ * ~~~~
+ */
+#[cfg(not(stage0))]
+#[inline]
+pub fn fold_ref<T, U>(start: T, iter: &fn(f: &fn(&U) -> bool) -> bool, f: &fn(&mut T, &U)) -> T {
+    let mut result = start;
+    for iter |x| {
+        f(&mut result, x);
+    }
+    result
+}
+
+/**
+ * Return the sum of the items yielding by an iterator.
+ *
+ * # Example:
+ *
+ * ~~~~
+ * let xs: ~[int] = ~[1, 2, 3, 4];
+ * assert_eq!(do sum |f| { xs.each(f) }, 10);
+ * ~~~~
+ */
+#[cfg(not(stage0))]
+#[inline(always)]
+pub fn sum<T: Zero + Add<T, T>>(iter: &fn(f: &fn(&T) -> bool) -> bool) -> T {
+    fold_ref(Zero::zero::<T>(), iter, |a, x| *a = a.add(x))
+}
+
+/**
+ * Return the product of the items yielded by an iterator.
+ *
+ * # Example:
+ *
+ * ~~~~
+ * let xs: ~[int] = ~[1, 2, 3, 4];
+ * assert_eq!(do product |f| { xs.each(f) }, 24);
+ * ~~~~
+ */
+#[cfg(not(stage0))]
+#[inline(always)]
+pub fn product<T: One + Mul<T, T>>(iter: &fn(f: &fn(&T) -> bool) -> bool) -> T {
+    fold_ref(One::one::<T>(), iter, |a, x| *a = a.mul(x))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -254,4 +331,33 @@ mod tests {
         let xs = ~[8, 2, 3, 1, -5, 9, 11, 15];
         assert_eq!(min(|f| xs.each(f)).unwrap(), &-5);
     }
+
+    #[test]
+    fn test_fold() {
+        assert_eq!(fold(0i, |f| int::range(1, 5, f), |a, x| *a += x), 10);
+    }
+
+    #[test]
+    fn test_sum() {
+        let xs: ~[int] = ~[1, 2, 3, 4];
+        assert_eq!(do sum |f| { xs.each(f) }, 10);
+    }
+
+    #[test]
+    fn test_empty_sum() {
+        let xs: ~[int] = ~[];
+        assert_eq!(do sum |f| { xs.each(f) }, 0);
+    }
+
+    #[test]
+    fn test_product() {
+        let xs: ~[int] = ~[1, 2, 3, 4];
+        assert_eq!(do product |f| { xs.each(f) }, 24);
+    }
+
+    #[test]
+    fn test_empty_product() {
+        let xs: ~[int] = ~[];
+        assert_eq!(do product |f| { xs.each(f) }, 1);
+    }
 }

branches/try2/src/libcore/vec.rs

@@ -1445,6 +1445,46 @@ pub fn reverse<T>(v: &mut [T]) {
     }
 }
 
+/**
+ * Reverse part of a vector in place.
+ *
+ * Reverse the elements in the vector between `start` and `end - 1`.
+ *
+ * If either start or end do not represent valid positions in the vector, the
+ * vector is returned unchanged.
+ *
+ * # Arguments
+ *
+ * * `v` - The mutable vector to be modified
+ *
+ * * `start` - Index of the first element of the slice
+ *
+ * * `end` - Index one past the final element to be reversed.
+ *
+ * # Example
+ *
+ * Assume a mutable vector `v` contains `[1,2,3,4,5]`. After the call:
+ *
+ * ~~~
+ *
+ * reverse_part(v, 1, 4);
+ *
+ * ~~~
+ *
+ * `v` now contains `[1,4,3,2,5]`.
+ */
+pub fn reverse_part<T>(v: &mut [T], start: uint, end : uint) {
+    let sz = v.len();
+    if start >= sz || end > sz { return; }
+    let mut i = start;
+    let mut j = end - 1;
+    while i < j {
+        vec::swap(v, i, j);
+        i += 1;
+        j -= 1;
+    }
+}
+
 /// Returns a vector with the order of elements reversed
 pub fn reversed<T:Copy>(v: &const [T]) -> ~[T] {
     let mut rs: ~[T] = ~[];
@@ -1739,29 +1779,49 @@ pub fn each2_mut<U, T>(v1: &mut [U], v2: &mut [T], f: &fn(u: &mut U, t: &mut T)
  *
  * The total number of permutations produced is `len(v)!`.  If `v` contains
  * repeated elements, then some permutations are repeated.
+ *
+ * See [Algorithms to generate
+ * permutations](http://en.wikipedia.org/wiki/Permutation).
+ *
+ *  # Arguments
+ *
+ *  * `values` - A vector of values from which the permutations are
+ *  chosen
+ *
+ *  * `fun` - The function to iterate over the combinations
  */
-#[cfg(not(stage0))]
-pub fn each_permutation<T:Copy>(v: &[T], put: &fn(ts: &[T]) -> bool) -> bool {
-    let ln = len(v);
-    if ln <= 1 {
-        put(v);
-    } else {
-        // This does not seem like the most efficient implementation.  You
-        // could make far fewer copies if you put your mind to it.
-        let mut i = 0u;
-        while i < ln {
-            let elt = v[i];
-            let mut rest = slice(v, 0u, i).to_vec();
-            rest.push_all(const_slice(v, i+1u, ln));
-            for each_permutation(rest) |permutation| {
-                if !put(append(~[elt], permutation)) {
-                    return false;
-                }
-            }
-            i += 1u;
+pub fn each_permutation<T:Copy>(values: &[T], fun: &fn(perm : &[T]) -> bool) -> bool {
+    let length = values.len();
+    let mut permutation = vec::from_fn(length, |i| values[i]);
+    if length <= 1 {
+        fun(permutation);
+        return true;
+    }
+    let mut indices = vec::from_fn(length, |i| i);
+    loop {
+        if !fun(permutation) { return true; }
+        // find largest k such that indices[k] < indices[k+1]
+        // if no such k exists, all permutations have been generated
+        let mut k = length - 2;
+        while k > 0 && indices[k] >= indices[k+1] {
+            k -= 1;
+        }
+        if k == 0 && indices[0] > indices[1] { return true; }
+        // find largest l such that indices[k] < indices[l]
+        // k+1 is guaranteed to be such
+        let mut l = length - 1;
+        while indices[k] >= indices[l] {
+            l -= 1;
+        }
+        // swap indices[k] and indices[l]; sort indices[k+1..]
+        // (they're just reversed)
+        vec::swap(indices, k, l);
+        reverse_part(indices, k+1, length);
+        // fixup permutation based on indices
+        for uint::range(k, length) |i| {
+            permutation[i] = values[indices[i]];
         }
     }
-    return true;
 }
 
 /**
@@ -4730,6 +4790,53 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_reverse_part() {
+        let mut values = [1,2,3,4,5];
+        reverse_part(values,1,4);
+        assert_eq!(values, [1,4,3,2,5]);
+    }
+
+    #[test]
+    fn test_permutations0() {
+        let values = [];
+        let mut v : ~[~[int]] = ~[];
+        for each_permutation(values) |p| {
+            v.push(p.to_owned());
+        }
+        assert_eq!(v, ~[~[]]);
+    }
+
+    #[test]
+    fn test_permutations1() {
+        let values = [1];
+        let mut v : ~[~[int]] = ~[];
+        for each_permutation(values) |p| {
+            v.push(p.to_owned());
+        }
+        assert_eq!(v, ~[~[1]]);
+    }
+
+    #[test]
+    fn test_permutations2() {
+        let values = [1,2];
+        let mut v : ~[~[int]] = ~[];
+        for each_permutation(values) |p| {
+            v.push(p.to_owned());
+        }
+        assert_eq!(v, ~[~[1,2],~[2,1]]);
+    }
+
+    #[test]
+    fn test_permutations3() {
+        let values = [1,2,3];
+        let mut v : ~[~[int]] = ~[];
+        for each_permutation(values) |p| {
+            v.push(p.to_owned());
+        }
+        assert_eq!(v, ~[~[1,2,3],~[1,3,2],~[2,1,3],~[2,3,1],~[3,1,2],~[3,2,1]]);
+    }
+
     #[test]
     fn test_each_val() {
         use old_iter::CopyableNonstrictIter;

branches/try2/src/librustc/metadata/csearch.rs

@@ -234,14 +234,13 @@ pub fn get_field_type(tcx: ty::ctxt, class_id: ast::def_id,
     }
 }
 
-// Given a def_id for an impl or class, return the traits it implements,
-// or the empty vector if it's not for an impl or for a class that implements
-// traits
-pub fn get_impl_traits(tcx: ty::ctxt,
-                       def: ast::def_id) -> ~[@ty::TraitRef] {
+// Given a def_id for an impl, return the trait it implements,
+// if there is one.
+pub fn get_impl_trait(tcx: ty::ctxt,
+                      def: ast::def_id) -> Option<@ty::TraitRef> {
     let cstore = tcx.cstore;
     let cdata = cstore::get_crate_data(cstore, def.crate);
-    decoder::get_impl_traits(cdata, def.node, tcx)
+    decoder::get_impl_trait(cdata, def.node, tcx)
 }
 
 pub fn get_impl_method(cstore: @mut cstore::CStore,

branches/try2/src/librustc/metadata/decoder.rs

@@ -415,19 +415,20 @@ pub fn get_type_param_count(data: @~[u8], id: ast::node_id) -> uint {
     item_ty_param_count(lookup_item(id, data))
 }
 
-pub fn get_impl_traits(cdata: cmd,
+pub fn get_impl_trait(cdata: cmd,
                        id: ast::node_id,
-                       tcx: ty::ctxt) -> ~[@ty::TraitRef]
+                       tcx: ty::ctxt) -> Option<@ty::TraitRef>
 {
     let item_doc = lookup_item(id, cdata.data);
-    let mut results = ~[];
+    let mut result = None;
     for reader::tagged_docs(item_doc, tag_item_trait_ref) |tp| {
         let trait_ref =
             @parse_trait_ref_data(tp.data, cdata.cnum, tp.start, tcx,
                                   |_, did| translate_def_id(cdata, did));
-        results.push(trait_ref);
+        result = Some(trait_ref);
+        break;
     };
-    results
+    result
 }
 
 pub fn get_impl_method(intr: @ident_interner, cdata: cmd, id: ast::node_id,

branches/try2/src/librustc/middle/trans/base.rs

@@ -2228,8 +2228,7 @@ pub fn register_fn_fuller(ccx: @CrateContext,
         mangle_exported_name(ccx, /*bad*/copy path, node_type)
     };
 
-    // XXX: Bad copy.
-    let llfn: ValueRef = decl_fn(ccx.llmod, copy ps, cc, llfty);
+    let llfn: ValueRef = decl_fn(ccx.llmod, ps, cc, llfty);
     ccx.item_symbols.insert(node_id, ps);
 
     // FIXME #4404 android JNI hacks

branches/try2/src/librustc/middle/trans/datum.rs

@@ -101,7 +101,6 @@ use middle::ty;
 use util::common::indenter;
 use util::ppaux::ty_to_str;
 
-use core::container::Set; // XXX: this should not be necessary
 use core::to_bytes;
 use syntax::ast;
 use syntax::codemap::span;

branches/try2/src/librustc/middle/trans/meth.rs

@@ -795,8 +795,11 @@ pub fn make_impl_vtable(ccx: @CrateContext,
     let _icx = ccx.insn_ctxt("impl::make_impl_vtable");
     let tcx = ccx.tcx;
 
-    // XXX: This should support multiple traits.
-    let trt_id = ty::impl_trait_refs(tcx, impl_id)[0].def_id;
+    let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
+        Some(t_id) => t_id.def_id,
+        None       => ccx.sess.bug("make_impl_vtable: don't know how to \
+                                    make a vtable for a type impl!")
+    };
 
     let has_tps =
         !ty::lookup_item_type(ccx.tcx, impl_id).generics.type_param_defs.is_empty();