std: remove fold[lr] in favour of iterators

doc/tutorial-tasks.md

@@ -354,7 +354,7 @@ a single large vector of floats. Each task needs the full vector to perform its
 use extra::arc::ARC;
 
 fn pnorm(nums: &~[float], p: uint) -> float {
-    (vec::foldl(0.0, *nums, |a,b| a+(*b).pow(p as float) )).pow(1f / (p as float))
+    nums.iter().fold(0.0, |a,b| a+(*b).pow(p as float) ).pow(1f / (p as float))
 }
 
 fn main() {

src/libextra/dlist.rs

@@ -20,6 +20,7 @@ Do not use ==, !=, <, etc on doubly-linked lists -- it may not terminate.
 
 use core::prelude::*;
 
+use core::iterator::IteratorUtil;
 use core::managed;
 use core::old_iter;
 use core::vec;
@@ -110,7 +111,7 @@ pub fn from_elem<T>(data: T) -> @mut DList<T> {
 
 /// Creates a new dlist from a vector of elements, maintaining the same order
 pub fn from_vec<T:Copy>(vec: &[T]) -> @mut DList<T> {
-    do vec::foldl(DList(), vec) |list,data| {
+    do vec.iter().fold(DList()) |list,data| {
         list.push(*data); // Iterating left-to-right -- add newly to the tail.
         list
     }

src/libextra/list.rs

@@ -12,7 +12,7 @@
 
 use core::prelude::*;
 
-use core::vec;
+use core::iterator::IteratorUtil;
 
 #[deriving(Eq)]
 pub enum List<T> {
@@ -28,7 +28,7 @@ pub enum MutList<T> {
 
 /// Create a list from a vector
 pub fn from_vec<T:Copy>(v: &[T]) -> @List<T> {
-    vec::foldr(v, @Nil::<T>, |h, t| @Cons(*h, t))
+    v.rev_iter().fold(@Nil::<T>, |t, h| @Cons(*h, t))
 }
 
 /**

src/libextra/stats.rs

@@ -12,6 +12,7 @@
 
 use core::prelude::*;
 
+use core::iterator::*;
 use core::vec;
 use core::f64;
 use core::cmp;
@@ -36,17 +37,17 @@ pub trait Stats {
 
 impl<'self> Stats for &'self [f64] {
     fn sum(self) -> f64 {
-        vec::foldl(0.0, self, |p,q| p + *q)
+        self.iter().fold(0.0, |p,q| p + *q)
     }
 
     fn min(self) -> f64 {
         assert!(self.len() != 0);
-        vec::foldl(self[0], self, |p,q| cmp::min(p, *q))
+        self.iter().fold(self[0], |p,q| cmp::min(p, *q))
     }
 
     fn max(self) -> f64 {
         assert!(self.len() != 0);
-        vec::foldl(self[0], self, |p,q| cmp::max(p, *q))
+        self.iter().fold(self[0], |p,q| cmp::max(p, *q))
     }
 
     fn mean(self) -> f64 {

src/librustc/middle/const_eval.rs

@@ -18,6 +18,7 @@ use middle;
 use syntax::{ast, ast_map, ast_util, visit};
 use syntax::ast::*;
 
+use core::iterator::IteratorUtil;
 use core::float;
 use core::hashmap::{HashMap, HashSet};
 use core::vec;
@@ -72,7 +73,7 @@ pub fn join(a: constness, b: constness) -> constness {
 }
 
 pub fn join_all(cs: &[constness]) -> constness {
-    vec::foldl(integral_const, cs, |a, b| join(a, *b))
+    cs.iter().fold(integral_const, |a, b| join(a, *b))
 }
 
 pub fn classify(e: @expr,

src/librustc/middle/trans/cabi_arm.rs

@@ -17,6 +17,7 @@ use middle::trans::cabi::{ABIInfo, FnType, LLVMType};
 use middle::trans::common::{T_i8, T_i16, T_i32, T_i64};
 use middle::trans::common::{T_array, T_ptr, T_void};
 
+use core::iterator::IteratorUtil;
 use core::option::{Option, None, Some};
 use core::uint;
 use core::vec;
@@ -43,9 +44,8 @@ fn ty_align(ty: TypeRef) -> uint {
                 if llvm::LLVMIsPackedStruct(ty) == True {
                     1
                 } else {
-                    do vec::foldl(1, struct_tys(ty)) |a, t| {
+                    let str_tys = struct_tys(ty);
-                        uint::max(a, ty_align(*t))
+                    str_tys.iter().fold(1, |a, t| uint::max(a, ty_align(*t)))
-                    }
                 }
             }
             Array => {
@@ -68,13 +68,11 @@ fn ty_size(ty: TypeRef) -> uint {
             Double => 8,
             Struct => {
                 if llvm::LLVMIsPackedStruct(ty) == True {
-                    do vec::foldl(0, struct_tys(ty)) |s, t| {
+                    let str_tys = struct_tys(ty);
-                        s + ty_size(*t)
+                    str_tys.iter().fold(0, |s, t| s + ty_size(*t))
-                    }
                 } else {
-                    let size = do vec::foldl(0, struct_tys(ty)) |s, t| {
+                    let str_tys = struct_tys(ty);
-                        align(s, *t) + ty_size(*t)
+                    let size = str_tys.iter().fold(0, |s, t| align(s, *t) + ty_size(*t));
-                    };
                     align(size, ty)
                 }
             }

src/librustc/middle/trans/cabi_mips.rs

@@ -10,6 +10,7 @@
 
 use core::prelude::*;
 
+use core::iterator::IteratorUtil;
 use core::libc::c_uint;
 use core::ptr;
 use core::uint;
@@ -56,9 +57,8 @@ fn ty_align(ty: TypeRef) -> uint {
               if llvm::LLVMIsPackedStruct(ty) == True {
                 1
               } else {
-                do vec::foldl(1, struct_tys(ty)) |a, t| {
+                let str_tys = struct_tys(ty);
-                    uint::max(a, ty_align(*t))
+                str_tys.iter().fold(1, |a, t| uint::max(a, ty_align(*t)))
-                }
               }
             }
             Array => {
@@ -81,13 +81,11 @@ fn ty_size(ty: TypeRef) -> uint {
             Double => 8,
             Struct => {
                 if llvm::LLVMIsPackedStruct(ty) == True {
-                    do vec::foldl(0, struct_tys(ty)) |s, t| {
+                    let str_tys = struct_tys(ty);
-                        s + ty_size(*t)
+                    str_tys.iter().fold(0, |s, t| s + ty_size(*t))
-                    }
                 } else {
-                    let size = do vec::foldl(0, struct_tys(ty)) |s, t| {
+                    let str_tys = struct_tys(ty);
-                        align(s, *t) + ty_size(*t)
+                    let size = str_tys.iter().fold(0, |s, t| align(s, *t) + ty_size(*t));
-                    };
                     align(size, ty)
                 }
             }

src/librustc/middle/trans/cabi_x86_64.rs

@@ -19,6 +19,7 @@ use lib::llvm::True;
 use middle::trans::common::*;
 use middle::trans::cabi::*;
 
+use core::iterator::IteratorUtil;
 use core::libc::c_uint;
 use core::option;
 use core::option::Option;
@@ -80,9 +81,8 @@ fn classify_ty(ty: TypeRef) -> ~[x86_64_reg_class] {
                   if llvm::LLVMIsPackedStruct(ty) == True {
                     1
                   } else {
-                    do vec::foldl(1, struct_tys(ty)) |a, t| {
+                    let str_tys = struct_tys(ty);
-                      uint::max(a, ty_align(*t))
+                    str_tys.iter().fold(1, |a, t| uint::max(a, ty_align(*t)))
-                    }
                   }
                 }
                 Array => {
@@ -104,16 +104,14 @@ fn classify_ty(ty: TypeRef) -> ~[x86_64_reg_class] {
                 Float => 4,
                 Double => 8,
                 Struct => {
-                  if llvm::LLVMIsPackedStruct(ty) == True {
+                    if llvm::LLVMIsPackedStruct(ty) == True {
-                    do vec::foldl(0, struct_tys(ty)) |s, t| {
+                        let str_tys = struct_tys(ty);
-                      s + ty_size(*t)
+                        str_tys.iter().fold(0, |s, t| s + ty_size(*t))
+                    } else {
+                        let str_tys = struct_tys(ty);
+                        let size = str_tys.iter().fold(0, |s, t| align(s, *t) + ty_size(*t));
+                        align(size, ty)
                     }
-                  } else {
-                    let size = do vec::foldl(0, struct_tys(ty)) |s, t| {
-                      align(s, *t) + ty_size(*t)
-                    };
-                    align(size, ty)
-                  }
                 }
                 Array => {
                   let len = llvm::LLVMGetArrayLength(ty) as uint;

src/librustdoc/desc_to_brief_pass.rs

@@ -24,6 +24,7 @@ use fold::Fold;
 use fold;
 use pass::Pass;
 
+use core::iterator::IteratorUtil;
 use core::str;
 use core::util;
 use core::vec;
@@ -150,7 +151,7 @@ pub fn paragraphs(s: &str) -> ~[~str] {
     for str::each_line_any(s) |line| { lines.push(line.to_owned()); }
     let mut whitespace_lines = 0;
     let mut accum = ~"";
-    let paras = do vec::foldl(~[], lines) |paras, line| {
+    let paras = do lines.iter().fold(~[]) |paras, line| {
         let mut res = paras;
 
         if str::is_whitespace(*line) {

src/librustdoc/doc.rs

@@ -14,6 +14,7 @@ use core::prelude::*;
 
 use doc;
 
+use core::iterator::IteratorUtil;
 use core::vec;
 
 pub type AstId = int;
@@ -174,7 +175,7 @@ pub struct IndexEntry {
 
 impl Doc {
     pub fn CrateDoc(&self) -> CrateDoc {
-        vec::foldl(None, self.pages, |_m, page| {
+        self.pages.iter().fold(None, |_m, page| {
             match copy *page {
               doc::CratePage(doc) => Some(doc),
               _ => None

src/librustdoc/pass.rs

@@ -11,6 +11,7 @@
 use core::prelude::*;
 
 use core::vec;
+use core::iterator::IteratorUtil;
 
 use astsrv;
 use doc;
@@ -30,7 +31,7 @@ pub fn run_passes(
     passes: ~[Pass]
 ) -> doc::Doc {
     let mut passno = 0;
-    do vec::foldl(doc, passes) |doc, pass| {
+    do passes.iter().fold(doc) |doc, pass| {
         debug!("pass #%d", passno);
         passno += 1;
         do time(copy pass.name) {

src/librustdoc/unindent_pass.rs

@@ -21,6 +21,7 @@ middle of a line, and each of the following lines is indented.
 
 use core::prelude::*;
 
+use core::iterator::IteratorUtil;
 use core::str;
 use core::uint;
 use core::vec;
@@ -36,7 +37,7 @@ fn unindent(s: &str) -> ~str {
     for str::each_line_any(s) |line| { lines.push(line.to_owned()); }
     let mut saw_first_line = false;
     let mut saw_second_line = false;
-    let min_indent = do vec::foldl(uint::max_value, lines)
+    let min_indent = do lines.iter().fold(uint::max_value)
         |min_indent, line| {
 
         // After we see the first non-whitespace line, look at

src/libstd/vec.rs

@@ -1066,64 +1066,6 @@ impl<'self, T:Copy> VectorVector<T> for &'self [&'self [T]] {
     }
 }
 
-/**
- * Reduces a vector from left to right.
- *
- * # Arguments
- * * `z` - initial accumulator value
- * * `v` - vector to iterate over
- * * `p` - a closure to operate on vector elements
- *
- * # Examples
- *
- * Sum all values in the vector [1, 2, 3]:
- *
- * ~~~ {.rust}
- * vec::foldl(0, [1, 2, 3], |a, b| a + *b);
- * ~~~
- *
- */
-pub fn foldl<'a, T, U>(z: T, v: &'a [U], p: &fn(t: T, u: &'a U) -> T) -> T {
-    let mut accum = z;
-    let mut i = 0;
-    let l = v.len();
-    while i < l {
-        // Use a while loop so that liveness analysis can handle moving
-        // the accumulator.
-        accum = p(accum, &v[i]);
-        i += 1;
-    }
-    accum
-}
-
-/**
- * Reduces a vector from right to left. Note that the argument order is
- * reversed compared to `foldl` to reflect the order they are provided to
- * the closure.
- *
- * # Arguments
- * * `v` - vector to iterate over
- * * `z` - initial accumulator value
- * * `p` - a closure to do operate on vector elements
- *
- * # Examples
- *
- * Sum all values in the vector [1, 2, 3]:
- *
- * ~~~ {.rust}
- * vec::foldr([1, 2, 3], 0, |a, b| a + *b);
- * ~~~
- *
- */
-pub fn foldr<'a, T, U>(v: &'a [T], mut z: U, p: &fn(t: &'a T, u: U) -> U) -> U {
-    let mut i = v.len();
-    while i > 0 {
-        i -= 1;
-        z = p(&v[i], z);
-    }
-    return z;
-}
-
 /// Return true if a vector contains an element with the given value
 pub fn contains<T:Eq>(v: &[T], x: &T) -> bool {
     for each(v) |elt| { if *x == *elt { return true; } }
@@ -1974,7 +1916,7 @@ impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
     /// Reduce a vector from right to left
     #[inline]
     fn foldr<'a, U>(&'a self, z: U, p: &fn(t: &'a T, u: U) -> U) -> U {
-        foldr(*self, z, p)
+        self.rev_iter().fold(z, |u, t| p(t, u))
     }
 
     /// Apply a function to each element of a vector and return the results
@@ -3394,39 +3336,6 @@ mod tests {
         assert_eq!(v, ~[1, 3, 5]);
     }
 
-    #[test]
-    fn test_foldl() {
-        // Test on-stack fold.
-        let mut v = ~[1u, 2u, 3u];
-        let mut sum = foldl(0u, v, add);
-        assert_eq!(sum, 6u);
-
-        // Test on-heap fold.
-        v = ~[1u, 2u, 3u, 4u, 5u];
-        sum = foldl(0u, v, add);
-        assert_eq!(sum, 15u);
-    }
-
-    #[test]
-    fn test_foldl2() {
-        fn sub(a: int, b: &int) -> int {
-            a - *b
-        }
-        let v = ~[1, 2, 3, 4];
-        let sum = foldl(0, v, sub);
-        assert_eq!(sum, -10);
-    }
-
-    #[test]
-    fn test_foldr() {
-        fn sub(a: &int, b: int) -> int {
-            *a - b
-        }
-        let v = ~[1, 2, 3, 4];
-        let sum = foldr(v, 0, sub);
-        assert_eq!(sum, -2);
-    }
-
     #[test]
     fn test_each_empty() {
         for each::<int>([]) |_v| {
@@ -4234,38 +4143,6 @@ mod tests {
         };
     }
 
-    #[test]
-    #[ignore(windows)]
-    #[should_fail]
-    #[allow(non_implicitly_copyable_typarams)]
-    fn test_foldl_fail() {
-        let v = [(~0, @0), (~0, @0), (~0, @0), (~0, @0)];
-        let mut i = 0;
-        do foldl((~0, @0), v) |_a, _b| {
-            if i == 2 {
-                fail!()
-            }
-            i += 0;
-            (~0, @0)
-        };
-    }
-
-    #[test]
-    #[ignore(windows)]
-    #[should_fail]
-    #[allow(non_implicitly_copyable_typarams)]
-    fn test_foldr_fail() {
-        let v = [(~0, @0), (~0, @0), (~0, @0), (~0, @0)];
-        let mut i = 0;
-        do foldr(v, (~0, @0)) |_a, _b| {
-            if i == 2 {
-                fail!()
-            }
-            i += 0;
-            (~0, @0)
-        };
-    }
-
     #[test]
     #[ignore(windows)]
     #[should_fail]

src/libsyntax/attr.rs

@@ -19,6 +19,7 @@ use codemap::BytePos;
 use diagnostic::span_handler;
 use parse::comments::{doc_comment_style, strip_doc_comment_decoration};
 
+use core::iterator::IteratorUtil;
 use core::hashmap::HashSet;
 use core::vec;
 use extra;
@@ -313,7 +314,7 @@ pub enum inline_attr {
 /// True if something like #[inline] is found in the list of attrs.
 pub fn find_inline_attr(attrs: &[ast::attribute]) -> inline_attr {
     // FIXME (#2809)---validate the usage of #[inline] and #[inline(always)]
-    do vec::foldl(ia_none, attrs) |ia,attr| {
+    do attrs.iter().fold(ia_none) |ia,attr| {
         match attr.node.value.node {
           ast::meta_word(@~"inline") => ia_hint,
           ast::meta_list(@~"inline", ref items) => {

src/libsyntax/ext/deriving/iter_bytes.rs

@@ -16,7 +16,7 @@ use ext::base::ExtCtxt;
 use ext::build::AstBuilder;
 use ext::deriving::generic::*;
 
-use core::vec;
+use core::iterator::IteratorUtil;
 
 pub fn expand_deriving_iter_bytes(cx: @ExtCtxt,
                                   span: span,
@@ -85,7 +85,7 @@ fn iter_bytes_substructure(cx: @ExtCtxt, span: span, substr: &Substructure) -> @
         cx.span_bug(span, "#[deriving(IterBytes)] needs at least one field");
     }
 
-    do vec::foldl(exprs[0], exprs.slice(1, exprs.len())) |prev, me| {
+    do exprs.slice(1, exprs.len()).iter().fold(exprs[0]) |prev, me| {
         cx.expr_binary(span, and, prev, *me)
     }
 }

src/libsyntax/ext/expand.rs

@@ -27,6 +27,7 @@ use parse::token::{ident_to_str, intern, fresh_name};
 use visit;
 use visit::{Visitor,mk_vt};
 
+use core::iterator::IteratorUtil;
 use core::vec;
 
 pub fn expand_expr(extsbox: @mut SyntaxEnv,
@@ -128,7 +129,7 @@ pub fn expand_mod_items(extsbox: @mut SyntaxEnv,
     // decorated with "item decorators", then use that function to transform
     // the item into a new set of items.
     let new_items = do vec::flat_map(module_.items) |item| {
-        do vec::foldr(item.attrs, ~[*item]) |attr, items| {
+        do item.attrs.rev_iter().fold(~[*item]) |items, attr| {
             let mname = attr::get_attr_name(attr);
 
             match (*extsbox).find(&intern(*mname)) {

src/libsyntax/ext/tt/macro_parser.rs

@@ -129,12 +129,12 @@ pub fn copy_up(mpu: &matcher_pos_up) -> ~MatcherPos {
 }
 
 pub fn count_names(ms: &[matcher]) -> uint {
-    vec::foldl(0u, ms, |ct, m| {
+    do ms.iter().fold(0) |ct, m| {
         ct + match m.node {
           match_tok(_) => 0u,
           match_seq(ref more_ms, _, _, _, _) => count_names((*more_ms)),
           match_nonterminal(_,_,_) => 1u
-        }})
+        }}
 }
 
 pub fn initial_matcher_pos(ms: ~[matcher], sep: Option<Token>, lo: BytePos)

src/libsyntax/ext/tt/transcribe.rs

@@ -19,9 +19,9 @@ use parse::token::{EOF, INTERPOLATED, IDENT, Token, nt_ident};
 use parse::token::{ident_to_str};
 use parse::lexer::TokenAndSpan;
 
+use core::iterator::IteratorUtil;
 use core::hashmap::HashMap;
 use core::option;
-use core::vec;
 
 ///an unzipping of `token_tree`s
 struct TtFrame {
@@ -113,9 +113,7 @@ fn lookup_cur_matched_by_matched(r: &mut TtReader,
           matched_seq(ref ads, _) => ads[*idx]
         }
     }
-    let r = &mut *r;
+    r.repeat_idx.iter().fold(start, red)
-    let repeat_idx = &r.repeat_idx;
-    vec::foldl(start, *repeat_idx, red)
 }
 
 fn lookup_cur_matched(r: &mut TtReader, name: ident) -> @named_match {
@@ -152,10 +150,10 @@ fn lockstep_iter_size(t: &token_tree, r: &mut TtReader) -> lis {
     }
     match *t {
       tt_delim(ref tts) | tt_seq(_, ref tts, _, _) => {
-        vec::foldl(lis_unconstrained, *tts, |lis, tt| {
+        do tts.iter().fold(lis_unconstrained) |lis, tt| {
             let lis2 = lockstep_iter_size(tt, r);
             lis_merge(lis, lis2)
-        })
+        }
       }
       tt_tok(*) => lis_unconstrained,
       tt_nonterminal(_, name) => match *lookup_cur_matched(r, name) {

src/test/compile-fail/block-arg-as-stmt-with-value.rs

@@ -8,12 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::vec;
+use std::iterator::IteratorUtil;
 
 fn compute1() -> float {
     let v = ~[0f, 1f, 2f, 3f];
 
-    do vec::foldl(0f, v) |x, y| { x + *y } - 10f
+    do v.iter().fold(0f) |x, y| { x + *y } - 10f
     //~^ ERROR mismatched types: expected `()`
 }
 

src/test/compile-fail/issue-3044.rs

@@ -8,13 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::vec;
+use std::iterator::IteratorUtil;
 
 fn main() {
     let needlesArr: ~[char] = ~['a', 'f'];
-    do vec::foldr(needlesArr) |x, y| {
+    do needlesArr.iter().fold() |x, y| {
     }
-    //~^ ERROR 2 parameters were supplied (including the closure passed by the `do` keyword)
+    //~^ ERROR 1 parameter were supplied (including the closure passed by the `do` keyword)
     //
     // the first error is, um, non-ideal.
 }

src/test/run-pass/block-arg-can-be-followed-by-binop.rs

@@ -14,7 +14,7 @@ pub fn main() {
     let v = ~[-1f, 0f, 1f, 2f, 3f];
 
     // Trailing expressions don't require parentheses:
-    let y = do vec::foldl(0f, v) |x, y| { x + *y } + 10f;
+    let y = do v.iter().fold(0f) |x, y| { x + *y } + 10f;
 
     assert_eq!(y, 15f);
 }

src/test/run-pass/block-arg-can-be-followed-by-block-arg.rs

@@ -13,6 +13,6 @@ use std::vec;
 pub fn main() {
     fn f(i: &fn() -> uint) -> uint { i() }
     let v = ~[-1f, 0f, 1f, 2f, 3f];
-    let z = do do vec::foldl(f, v) |x, _y| { x } { 22u };
+    let z = do do v.iter().fold(f) |x, _y| { x } { 22u };
     assert_eq!(z, 22u);
 }

src/test/run-pass/block-arg-can-be-followed-by-call.rs

@@ -13,6 +13,6 @@ use std::vec;
 pub fn main() {
     fn f(i: uint) -> uint { i }
     let v = ~[-1f, 0f, 1f, 2f, 3f];
-    let z = do vec::foldl(f, v) |x, _y| { x } (22u);
+    let z = do v.iter().fold(f) |x, _y| { x } (22u);
     assert_eq!(z, 22u);
 }

src/test/run-pass/block-arg-in-parentheses.rs

@@ -8,25 +8,26 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::iterator::IteratorUtil;
 use std::vec;
 
 fn w_semi(v: ~[int]) -> int {
     // the semicolon causes compiler not to
     // complain about the ignored return value:
-    do vec::foldl(0, v) |x,y| { x+*y };
+    do v.iter().fold(0) |x,y| { x+*y };
     -10
 }
 
 fn w_paren1(v: ~[int]) -> int {
-    (do vec::foldl(0, v) |x,y| { x+*y }) - 10
+    (do v.iter().fold(0) |x,y| { x+*y }) - 10
 }
 
 fn w_paren2(v: ~[int]) -> int {
-    (do vec::foldl(0, v) |x,y| { x+*y} - 10)
+    (do v.iter().fold(0) |x,y| { x+*y} - 10)
 }
 
 fn w_ret(v: ~[int]) -> int {
-    return do vec::foldl(0, v) |x,y| { x+*y } - 10;
+    return do v.iter().fold(0) |x,y| { x+*y } - 10;
 }
 
 pub fn main() {

src/test/run-pass/block-arg.rs

@@ -51,9 +51,9 @@ pub fn main() {
 
 
     // Lower precedence than binary operations:
-    let w = do vec::foldl(0f, v) |x, y| { x + *y } + 10f;
+    let w = do v.iter().fold(0f) |x, y| { x + *y } + 10f;
-    let y = do vec::foldl(0f, v) |x, y| { x + *y } + 10f;
+    let y = do v.iter().fold(0f) |x, y| { x + *y } + 10f;
-    let z = 10f + do vec::foldl(0f, v) |x, y| { x + *y };
+    let z = 10f + do v.iter().fold(0f) |x, y| { x + *y };
     assert_eq!(w, y);
     assert_eq!(y, z);