---

yaml
---
r: 140904
b: refs/heads/try2
c: 77c98f0
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: af54d58891505a67aaab5365b957679b0c593eb7
+refs/heads/try2: 77c98f081509733af957af6ed7b0b277e5f57871
 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/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();

branches/try2/src/librustc/middle/ty.rs

@@ -3883,23 +3883,23 @@ pub fn trait_method_def_ids(cx: ctxt, id: ast::def_id) -> @~[def_id] {
         || @csearch::get_trait_method_def_ids(cx.cstore, id))
 }
 
-pub fn impl_trait_refs(cx: ctxt, id: ast::def_id) -> ~[@TraitRef] {
+pub fn impl_trait_ref(cx: ctxt, id: ast::def_id) -> Option<@TraitRef> {
     if id.crate == ast::local_crate {
-        debug!("(impl_traits) searching for trait impl %?", id);
+        debug!("(impl_trait_ref) searching for trait impl %?", id);
         match cx.items.find(&id.node) {
            Some(&ast_map::node_item(@ast::item {
                         node: ast::item_impl(_, opt_trait, _, _),
                         _},
                     _)) => {
                match opt_trait {
-                   Some(t) => ~[ty::node_id_to_trait_ref(cx, t.ref_id)],
-                   None => ~[]
+                   Some(t) => Some(ty::node_id_to_trait_ref(cx, t.ref_id)),
+                   None => None
                }
            }
-           _ => ~[]
+           _ => None
         }
     } else {
-        csearch::get_impl_traits(cx, id)
+        csearch::get_impl_trait(cx, id)
     }
 }
 

branches/try2/src/librustc/middle/typeck/check/vtable.rs

@@ -261,24 +261,14 @@ fn lookup_vtable(vcx: &VtableContext,
                         }
                         impls_seen.insert(im.did);
 
-                        // ty::impl_traits gives us the list of all
-                        // traits that im implements. Again, usually
-                        // there's just one.
+                        // ty::impl_traits gives us the trait im implements,
+                        // if there is one (there's either zero or one).
                         //
-                        // For example, if im represented the struct
-                        // in:
-                        //
-                        //   struct foo : baz<int>, bar, quux { ... }
-                        //
-                        // then ty::impl_traits would return
-                        //
-                        //   ~[baz<int>, bar, quux]
-                        //
-                        // For each of the traits foo implements, if
-                        // it's the same trait as trait_ref, we need to
+                        // If foo implements a trait t, and if t is the
+                        // same trait as trait_ref, we need to
                         // unify it with trait_ref in order to get all
                         // the ty vars sorted out.
-                        for ty::impl_trait_refs(tcx, im.did).each |&of_trait_ref|
+                        for ty::impl_trait_ref(tcx, im.did).each |&of_trait_ref|
                         {
                             if of_trait_ref.def_id != trait_ref.def_id { loop; }
 
@@ -456,8 +446,12 @@ fn connect_trait_tps(vcx: &VtableContext,
 {
     let tcx = vcx.tcx();
 
-    // XXX: This should work for multiple traits.
-    let impl_trait_ref = ty::impl_trait_refs(tcx, impl_did)[0];
+    let impl_trait_ref = match ty::impl_trait_ref(tcx, impl_did) {
+        Some(t) => t,
+        None => vcx.tcx().sess.span_bug(location_info.span,
+                                  "connect_trait_tps invoked on a type impl")
+    };
+
     let impl_trait_ref = (*impl_trait_ref).subst(tcx, impl_substs);
     relate_trait_refs(vcx, location_info, &impl_trait_ref, trait_ref);
 }

branches/try2/src/librustc/middle/typeck/coherence.rs

@@ -16,7 +16,7 @@
 
 
 use driver;
-use metadata::csearch::{each_path, get_impl_traits};
+use metadata::csearch::{each_path, get_impl_trait};
 use metadata::csearch::{get_impls_for_mod};
 use metadata::csearch;
 use metadata::cstore::{CStore, iter_crate_data};
@@ -898,13 +898,13 @@ pub impl CoherenceChecker {
 
             let self_type = lookup_item_type(self.crate_context.tcx,
                                              implementation.did);
-            let associated_traits = get_impl_traits(self.crate_context.tcx,
+            let associated_traits = get_impl_trait(self.crate_context.tcx,
                                                     implementation.did);
 
             // Do a sanity check to make sure that inherent methods have base
             // types.
 
-            if associated_traits.len() == 0 {
+            if associated_traits.is_none() {
                 match get_base_type_def_id(self.inference_context,
                                            dummy_sp(),
                                            self_type.ty) {
@@ -940,7 +940,7 @@ pub impl CoherenceChecker {
                 Some(base_type_def_id) => {
                     // inherent methods apply to `impl Type` but not
                     // `impl Trait for Type`:
-                    if associated_traits.len() == 0 {
+                    if associated_traits.is_none() {
                         self.add_inherent_method(base_type_def_id,
                                                  *implementation);
                     }