std::at_vec and vec: Unify build_sized, build_sized_opt into build

These functions have very few users since they are mostly replaced by
iterator-based constructions.

Convert a few remaining users in-tree, and reduce the number of
functions by basically renaming build_sized_opt to build, and removing
the other two. This for both the vec and the at_vec versions.

src/libextra/base64.rs

@@ -315,11 +315,8 @@ mod test {
         use std::vec;
 
         do 1000.times {
-            let v: ~[u8] = do vec::build |push| {
-                do task_rng().gen_uint_range(1, 100).times {
-                    push(random());
-                }
-            };
+            let times = task_rng().gen_uint_range(1, 100);
+            let v = vec::from_fn(times, |_| random::<u8>());
             assert_eq!(v.to_base64(STANDARD).from_base64().unwrap(), v);
         }
     }

src/librustc/middle/typeck/infer/combine.rs

@@ -61,7 +61,6 @@ use middle::typeck::infer::{TypeTrace};
 use util::common::indent;
 
 use std::result;
-use std::vec;
 use syntax::ast::{Onceness, purity};
 use syntax::ast;
 use syntax::opt_vec;

src/librustc/middle/typeck/infer/region_inference/mod.rs

@@ -373,14 +373,12 @@ impl RegionVarBindings {
 
     pub fn vars_created_since_snapshot(&mut self, snapshot: uint)
                                        -> ~[RegionVid] {
-        do vec::build |push| {
-            for &elt in self.undo_log.slice_from(snapshot).iter() {
-                match elt {
-                    AddVar(vid) => push(vid),
-                    _ => ()
-                }
-            }
-        }
+        self.undo_log.slice_from(snapshot).iter()
+            .filter_map(|&elt| match elt {
+                AddVar(vid) => Some(vid),
+                _ => None
+            })
+            .collect()
     }
 
     pub fn tainted(&mut self, snapshot: uint, r0: Region) -> ~[Region] {

src/libstd/at_vec.rs

@@ -33,42 +33,7 @@ pub fn capacity<T>(v: @[T]) -> uint {
 /**
  * Builds a vector by calling a provided function with an argument
  * function that pushes an element to the back of a vector.
- * This version takes an initial size for the vector.
- *
- * # Arguments
- *
- * * size - An initial size of the vector to reserve
- * * builder - A function that will construct the vector. It receives
- *             as an argument a function that will push an element
- *             onto the vector being constructed.
- */
-#[inline]
-pub fn build_sized<A>(size: uint, builder: &fn(push: &fn(v: A))) -> @[A] {
-    let mut vec = @[];
-    unsafe { raw::reserve(&mut vec, size); }
-    builder(|x| unsafe { raw::push(&mut vec, x) });
-    vec
-}
-
-/**
- * Builds a vector by calling a provided function with an argument
- * function that pushes an element to the back of a vector.
- *
- * # Arguments
- *
- * * builder - A function that will construct the vector. It receives
- *             as an argument a function that will push an element
- *             onto the vector being constructed.
- */
-#[inline]
-pub fn build<A>(builder: &fn(push: &fn(v: A))) -> @[A] {
-    build_sized(4, builder)
-}
-
-/**
- * Builds a vector by calling a provided function with an argument
- * function that pushes an element to the back of a vector.
- * This version takes an initial size for the vector.
+ * The initial size for the vector may optionally be specified
  *
  * # Arguments
  *
@@ -78,8 +43,11 @@ pub fn build<A>(builder: &fn(push: &fn(v: A))) -> @[A] {
  *             onto the vector being constructed.
  */
 #[inline]
-pub fn build_sized_opt<A>(size: Option<uint>, builder: &fn(push: &fn(v: A))) -> @[A] {
-    build_sized(size.unwrap_or_default(4), builder)
+pub fn build<A>(size: Option<uint>, builder: &fn(push: &fn(v: A))) -> @[A] {
+    let mut vec = @[];
+    unsafe { raw::reserve(&mut vec, size.unwrap_or_default(4)); }
+    builder(|x| unsafe { raw::push(&mut vec, x) });
+    vec
 }
 
 // Appending
@@ -88,7 +56,7 @@ pub fn build_sized_opt<A>(size: Option<uint>, builder: &fn(push: &fn(v: A))) ->
 /// `lhs`. Afterwards, the `lhs` is then returned for use again.
 #[inline]
 pub fn append<T:Clone>(lhs: @[T], rhs: &[T]) -> @[T] {
-    do build_sized(lhs.len() + rhs.len()) |push| {
+    do build(Some(lhs.len() + rhs.len())) |push| {
         for x in lhs.iter() {
             push((*x).clone());
         }
@@ -101,7 +69,7 @@ pub fn append<T:Clone>(lhs: @[T], rhs: &[T]) -> @[T] {
 
 /// Apply a function to each element of a vector and return the results
 pub fn map<T, U>(v: &[T], f: &fn(x: &T) -> U) -> @[U] {
-    do build_sized(v.len()) |push| {
+    do build(Some(v.len())) |push| {
         for elem in v.iter() {
             push(f(elem));
         }
@@ -115,7 +83,7 @@ pub fn map<T, U>(v: &[T], f: &fn(x: &T) -> U) -> @[U] {
  * to the value returned by the function `op`.
  */
 pub fn from_fn<T>(n_elts: uint, op: &fn(uint) -> T) -> @[T] {
-    do build_sized(n_elts) |push| {
+    do build(Some(n_elts)) |push| {
         let mut i: uint = 0u;
         while i < n_elts { push(op(i)); i += 1u; }
     }
@@ -128,7 +96,7 @@ pub fn from_fn<T>(n_elts: uint, op: &fn(uint) -> T) -> @[T] {
  * to the value `t`.
  */
 pub fn from_elem<T:Clone>(n_elts: uint, t: T) -> @[T] {
-    do build_sized(n_elts) |push| {
+    do build(Some(n_elts)) |push| {
         let mut i: uint = 0u;
         while i < n_elts {
             push(t.clone());
@@ -312,7 +280,7 @@ mod test {
     fn test() {
         // Some code that could use that, then:
         fn seq_range(lo: uint, hi: uint) -> @[uint] {
-            do build |push| {
+            do build(None) |push| {
                 for i in range(lo, hi) {
                     push(i);
                 }
@@ -359,7 +327,7 @@ mod test {
     fn bench_build_sized(b: &mut bh) {
         let len = 64;
         do b.iter {
-            build_sized(len, |push| for i in range(0, 1024) { push(i) });
+            build(Some(len), |push| for i in range(0, 1024) { push(i) });
         }
     }
 
@@ -367,7 +335,7 @@ mod test {
     fn bench_build(b: &mut bh) {
         do b.iter {
             for i in range(0, 95) {
-                build(|push| push(i));
+                build(None, |push| push(i));
             }
         }
     }

src/libstd/io.rs

@@ -777,7 +777,7 @@ impl<T:Reader> ReaderUtil for T {
     }
 
     fn read_lines(&self) -> ~[~str] {
-        do vec::build |push| {
+        do vec::build(None) |push| {
             do self.each_line |line| {
                 push(line.to_owned());
                 true

src/libstd/vec.rs

@@ -194,41 +194,7 @@ pub fn with_capacity<T>(capacity: uint) -> ~[T] {
 /**
  * Builds a vector by calling a provided function with an argument
  * function that pushes an element to the back of a vector.
- * This version takes an initial capacity for the vector.
- *
- * # Arguments
- *
- * * size - An initial size of the vector to reserve
- * * builder - A function that will construct the vector. It receives
- *             as an argument a function that will push an element
- *             onto the vector being constructed.
- */
-#[inline]
-pub fn build_sized<A>(size: uint, builder: &fn(push: &fn(v: A))) -> ~[A] {
-    let mut vec = with_capacity(size);
-    builder(|x| vec.push(x));
-    vec
-}
-
-/**
- * Builds a vector by calling a provided function with an argument
- * function that pushes an element to the back of a vector.
- *
- * # Arguments
- *
- * * builder - A function that will construct the vector. It receives
- *             as an argument a function that will push an element
- *             onto the vector being constructed.
- */
-#[inline]
-pub fn build<A>(builder: &fn(push: &fn(v: A))) -> ~[A] {
-    build_sized(4, builder)
-}
-
-/**
- * Builds a vector by calling a provided function with an argument
- * function that pushes an element to the back of a vector.
- * This version takes an initial size for the vector.
+ * The initial capacity for the vector may optionally be specified.
  *
  * # Arguments
  *
@@ -238,8 +204,10 @@ pub fn build<A>(builder: &fn(push: &fn(v: A))) -> ~[A] {
  *             onto the vector being constructed.
  */
 #[inline]
-pub fn build_sized_opt<A>(size: Option<uint>, builder: &fn(push: &fn(v: A))) -> ~[A] {
-    build_sized(size.unwrap_or_default(4), builder)
+pub fn build<A>(size: Option<uint>, builder: &fn(push: &fn(v: A))) -> ~[A] {
+    let mut vec = with_capacity(size.unwrap_or_default(4));
+    builder(|x| vec.push(x));
+    vec
 }
 
 /// An iterator over the slices of a vector separated by elements that
@@ -3248,7 +3216,7 @@ mod tests {
     #[test]
     #[should_fail]
     fn test_build_fail() {
-        do build |push| {
+        do build(None) |push| {
             push((~0, @0));
             push((~0, @0));
             push((~0, @0));

src/libsyntax/ext/deriving/generic.rs

@@ -958,7 +958,7 @@ fn create_struct_pattern(cx: @ExtCtxt,
     // struct_type is definitely not Unknown, since struct_def.fields
     // must be nonempty to reach here
     let pattern = if struct_type == Record {
-        let field_pats = do vec::build |push| {
+        let field_pats = do vec::build(None) |push| {
             for (&pat, &(id, _)) in subpats.iter().zip(ident_expr.iter()) {
                 // id is guaranteed to be Some
                 push(ast::FieldPat { ident: id.unwrap(), pat: pat })

src/test/run-pass/issue-3563-3.rs

@@ -66,7 +66,7 @@ impl Drop for AsciiArt {
 fn AsciiArt(width: uint, height: uint, fill: char) -> AsciiArt {
     // Use an anonymous function to build a vector of vectors containing
     // blank characters for each position in our canvas.
-    let lines = do vec::build_sized(height) |push| {
+    let lines = do vec::build(Some(height)) |push| {
             do height.times {
                 push(vec::from_elem(width, '.'));
             }