diff --git a/src/doc/book/iterators.md b/src/doc/book/iterators.md index 5622326d20c31..0c4f804126631 100644 --- a/src/doc/book/iterators.md +++ b/src/doc/book/iterators.md @@ -311,10 +311,12 @@ for i in (1..100).filter(|&x| x % 2 == 0) { ``` This will print all of the even numbers between one and a hundred. -(Note that because `filter` doesn't consume the elements that are -being iterated over, it is passed a reference to each element, and -thus the filter predicate uses the `&x` pattern to extract the integer -itself.) +(Note that, unlike `map`, the closure passed to `filter` is passed a reference +to the element instead of the element itself. The filter predicate here uses +the `&x` pattern to extract the integer. The filter closure is passed a +reference because it returns `true` or `false` instead of the element, +so the `filter` implementation must retain ownership to put the elements +into the newly constructed iterator.) You can chain all three things together: start with an iterator, adapt it a few times, and then consume the result. Check it out: diff --git a/src/doc/book/ownership.md b/src/doc/book/ownership.md index 8f15544b20b2b..70d71c14ddf16 100644 --- a/src/doc/book/ownership.md +++ b/src/doc/book/ownership.md @@ -157,7 +157,7 @@ this point of time). These two parts of the vector (the one on the stack and one on the heap) must agree with each other at all times with regards to things like the length, capacity etc. -When we move `v` to `v2`, rust actually does a bitwise copy of the vector +When we move `v` to `v2`, Rust actually does a bitwise copy of the vector object `v` into the stack allocation represented by `v2`. This shallow copy does not create a copy of the heap allocation containing the actual data. Which means that there would be two pointers to the contents of the vector diff --git a/src/doc/nomicon/other-reprs.md b/src/doc/nomicon/other-reprs.md index 2639c1d4d6f76..b124f3ffc4652 100644 --- a/src/doc/nomicon/other-reprs.md +++ b/src/doc/nomicon/other-reprs.md @@ -57,7 +57,7 @@ These reprs have no effect on a struct. # repr(packed) -`repr(packed)` forces rust to strip any padding, and only align the type to a +`repr(packed)` forces Rust to strip any padding, and only align the type to a byte. This may improve the memory footprint, but will likely have other negative side-effects. diff --git a/src/doc/reference.md b/src/doc/reference.md index 19c9b571a33c2..228af39483832 100644 --- a/src/doc/reference.md +++ b/src/doc/reference.md @@ -841,8 +841,8 @@ extern crate std as ruststd; // linking to 'std' under another name A _use declaration_ creates one or more local name bindings synonymous with some other [path](#paths). Usually a `use` declaration is used to shorten the -path required to refer to a module item. These declarations may appear at the -top of [modules](#modules) and [blocks](grammar.html#block-expressions). +path required to refer to a module item. These declarations may appear in +[modules](#modules) and [blocks](grammar.html#block-expressions), usually at the top. > **Note**: Unlike in many languages, > `use` declarations in Rust do *not* declare linkage dependency with external crates. @@ -1764,7 +1764,7 @@ pub mod submodule { # fn main() {} ``` -For a rust program to pass the privacy checking pass, all paths must be valid +For a Rust program to pass the privacy checking pass, all paths must be valid accesses given the two rules above. This includes all use statements, expressions, types, etc. @@ -3564,8 +3564,9 @@ Each instance of a trait object includes: each method of `SomeTrait` that `T` implements, a pointer to `T`'s implementation (i.e. a function pointer). -The purpose of trait objects is to permit "late binding" of methods. A call to -a method on a trait object is only resolved to a vtable entry at compile time. +The purpose of trait objects is to permit "late binding" of methods. Calling a +method on a trait object results in virtual dispatch at runtime: that is, a +function pointer is loaded from the trait object vtable and invoked indirectly. The actual implementation for each vtable entry can vary on an object-by-object basis. diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs index 6252e4888eb3c..eab69088aa2b9 100644 --- a/src/libcollections/slice.rs +++ b/src/libcollections/slice.rs @@ -407,7 +407,7 @@ impl [T] { } /// Returns an iterator over `size` elements of the slice at a - /// time. The chunks do not overlap. If `size` does not divide the + /// time. The chunks are slices and do not overlap. If `size` does not divide the /// length of the slice, then the last chunk will not have length /// `size`. /// @@ -433,7 +433,7 @@ impl [T] { } /// Returns an iterator over `chunk_size` elements of the slice at a time. - /// The chunks are mutable and do not overlap. If `chunk_size` does + /// The chunks are mutable slices, and do not overlap. If `chunk_size` does /// not divide the length of the slice, then the last chunk will not /// have length `chunk_size`. /// diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs index 49c3552083334..ae442e155c0d0 100644 --- a/src/libcollections/vec.rs +++ b/src/libcollections/vec.rs @@ -135,6 +135,49 @@ use super::range::RangeArgument; /// } /// ``` /// +/// # Indexing +/// +/// The Vec type allows to access values by index, because it implements the +/// `Index` trait. An example will be more explicit: +/// +/// ``` +/// let v = vec!(0, 2, 4, 6); +/// println!("{}", v[1]); // it will display '2' +/// ``` +/// +/// However be careful: if you try to access an index which isn't in the Vec, +/// your software will panic! You cannot do this: +/// +/// ```ignore +/// let v = vec!(0, 2, 4, 6); +/// println!("{}", v[6]); // it will panic! +/// ``` +/// +/// In conclusion: always check if the index you want to get really exists +/// before doing it. +/// +/// # Slicing +/// +/// A Vec can be mutable. Slices, on the other hand, are read-only objects. +/// To get a slice, use "&". Example: +/// +/// ``` +/// fn read_slice(slice: &[usize]) { +/// // ... +/// } +/// +/// let v = vec!(0, 1); +/// read_slice(&v); +/// +/// // ... and that's all! +/// // you can also do it like this: +/// let x : &[usize] = &v; +/// ``` +/// +/// In Rust, it's more common to pass slices as arguments rather than vectors +/// when you just want to provide a read access. The same goes for String and +/// &str. +/// /// # Capacity and reallocation /// /// The capacity of a vector is the amount of space allocated for any future diff --git a/src/libgetopts/lib.rs b/src/libgetopts/lib.rs index 57ce53e73b025..fe059076926ee 100644 --- a/src/libgetopts/lib.rs +++ b/src/libgetopts/lib.rs @@ -331,9 +331,8 @@ impl Matches { /// Returns the string argument supplied to one of several matching options or `None`. pub fn opts_str(&self, names: &[String]) -> Option { for nm in names { - match self.opt_val(&nm[..]) { - Some(Val(ref s)) => return Some(s.clone()), - _ => (), + if let Some(Val(ref s)) = self.opt_val(&nm[..]) { + return Some(s.clone()) } } None diff --git a/src/librustc_trans/back/link.rs b/src/librustc_trans/back/link.rs index 33734d615a621..76360dcc1b972 100644 --- a/src/librustc_trans/back/link.rs +++ b/src/librustc_trans/back/link.rs @@ -226,9 +226,8 @@ fn symbol_hash<'tcx>(tcx: &ty::ctxt<'tcx>, } fn get_symbol_hash<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) -> String { - match ccx.type_hashcodes().borrow().get(&t) { - Some(h) => return h.to_string(), - None => {} + if let Some(h) = ccx.type_hashcodes().borrow().get(&t) { + return h.to_string() } let mut symbol_hasher = ccx.symbol_hasher().borrow_mut(); @@ -315,9 +314,8 @@ pub fn mangle>(path: PI, hash: Option<&str>) - push(&mut n, &data); } - match hash { - Some(s) => push(&mut n, s), - None => {} + if let Some(s) = hash { + push(&mut n, s) } n.push('E'); // End name-sequence. diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs index e36905c6d90ea..161ab90c03a73 100644 --- a/src/librustc_trans/trans/base.rs +++ b/src/librustc_trans/trans/base.rs @@ -150,9 +150,8 @@ impl Drop for _InsnCtxt { pub fn push_ctxt(s: &'static str) -> _InsnCtxt { debug!("new InsnCtxt: {}", s); TASK_LOCAL_INSN_KEY.with(|slot| { - match slot.borrow_mut().as_mut() { - Some(ctx) => ctx.push(s), - None => {} + if let Some(ctx) = slot.borrow_mut().as_mut() { + ctx.push(s) } }); _InsnCtxt { @@ -198,9 +197,8 @@ fn get_extern_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str, did: DefId) -> ValueRef { - match ccx.externs().borrow().get(name) { - Some(n) => return *n, - None => (), + if let Some(n) = ccx.externs().borrow().get(name) { + return *n; } let f = declare::declare_rust_fn(ccx, name, fn_ty); @@ -238,9 +236,8 @@ pub fn get_extern_const<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, -> ValueRef { let name = ccx.sess().cstore.item_symbol(did); let ty = type_of(ccx, t); - match ccx.externs().borrow_mut().get(&name) { - Some(n) => return *n, - None => (), + if let Some(n) = ccx.externs().borrow_mut().get(&name) { + return *n; } // FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow? // FIXME(nagisa): investigate whether it can be changed into define_global @@ -2755,9 +2752,8 @@ fn contains_null(s: &str) -> bool { pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef { debug!("get_item_val(id=`{}`)", id); - match ccx.item_vals().borrow().get(&id).cloned() { - Some(v) => return v, - None => {} + if let Some(v) = ccx.item_vals().borrow().get(&id).cloned() { + return v; } let item = ccx.tcx().map.get(id); diff --git a/src/librustc_trans/trans/common.rs b/src/librustc_trans/trans/common.rs index bdc0f8539d600..7f7de0e872b6c 100644 --- a/src/librustc_trans/trans/common.rs +++ b/src/librustc_trans/trans/common.rs @@ -947,9 +947,8 @@ pub fn C_u8(ccx: &CrateContext, i: u8) -> ValueRef { // our boxed-and-length-annotated strings. pub fn C_cstr(cx: &CrateContext, s: InternedString, null_terminated: bool) -> ValueRef { unsafe { - match cx.const_cstr_cache().borrow().get(&s) { - Some(&llval) => return llval, - None => () + if let Some(&llval) = cx.const_cstr_cache().borrow().get(&s) { + return llval; } let sc = llvm::LLVMConstStringInContext(cx.llcx(), diff --git a/src/librustc_trans/trans/type_of.rs b/src/librustc_trans/trans/type_of.rs index 0f88269a2c9e9..24a7fd372f636 100644 --- a/src/librustc_trans/trans/type_of.rs +++ b/src/librustc_trans/trans/type_of.rs @@ -182,9 +182,8 @@ pub fn type_of_fn_from_ty<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, fty: Ty<'tcx>) // recursive types. For example, enum types rely on this behavior. pub fn sizing_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) -> Type { - match cx.llsizingtypes().borrow().get(&t).cloned() { - Some(t) => return t, - None => () + if let Some(t) = cx.llsizingtypes().borrow().get(&t).cloned() { + return t; } debug!("sizing_type_of {:?}", t); @@ -317,9 +316,8 @@ pub fn type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> Type { /// NB: If you update this, be sure to update `sizing_type_of()` as well. pub fn in_memory_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) -> Type { // Check the cache. - match cx.lltypes().borrow().get(&t) { - Some(&llty) => return llty, - None => () + if let Some(&llty) = cx.lltypes().borrow().get(&t) { + return llty; } debug!("type_of {:?}", t); diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs index 692d230446cda..1b97b3865d421 100644 --- a/src/librustdoc/html/render.rs +++ b/src/librustdoc/html/render.rs @@ -2734,18 +2734,19 @@ fn make_item_keywords(it: &clean::Item) -> String { fn get_index_search_type(item: &clean::Item, parent: Option) -> Option { - let decl = match item.inner { - clean::FunctionItem(ref f) => &f.decl, - clean::MethodItem(ref m) => &m.decl, - clean::TyMethodItem(ref m) => &m.decl, + let (decl, selfty) = match item.inner { + clean::FunctionItem(ref f) => (&f.decl, None), + clean::MethodItem(ref m) => (&m.decl, Some(&m.self_)), + clean::TyMethodItem(ref m) => (&m.decl, Some(&m.self_)), _ => return None }; let mut inputs = Vec::new(); // Consider `self` an argument as well. - if let Some(name) = parent { - inputs.push(Type { name: Some(name.to_ascii_lowercase()) }); + match parent.and_then(|p| selfty.map(|s| (p, s)) ) { + Some((_, &clean::SelfStatic)) | None => (), + Some((name, _)) => inputs.push(Type { name: Some(name.to_ascii_lowercase()) }), } inputs.extend(&mut decl.inputs.values.iter().map(|arg| { diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs index 6cad0d7d940d7..ffb15d157b066 100644 --- a/src/librustdoc/lib.rs +++ b/src/librustdoc/lib.rs @@ -385,9 +385,8 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche *s.borrow_mut() = analysis.take(); }); - match matches.opt_str("crate-name") { - Some(name) => krate.name = name, - None => {} + if let Some(name) = matches.opt_str("crate-name") { + krate.name = name } // Process all of the crate attributes, extracting plugin metadata along diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs index 6ce6777d11eff..78da9412212a9 100644 --- a/src/libstd/net/addr.rs +++ b/src/libstd/net/addr.rs @@ -467,9 +467,8 @@ impl ToSocketAddrs for str { type Iter = vec::IntoIter; fn to_socket_addrs(&self) -> io::Result> { // try to parse as a regular SocketAddr first - match self.parse().ok() { - Some(addr) => return Ok(vec![addr].into_iter()), - None => {} + if let Some(addr) = self.parse().ok() { + return Ok(vec![addr].into_iter()); } macro_rules! try_opt { diff --git a/src/libstd/net/parser.rs b/src/libstd/net/parser.rs index 46a0309dbb509..63eee6bcfded5 100644 --- a/src/libstd/net/parser.rs +++ b/src/libstd/net/parser.rs @@ -66,9 +66,8 @@ impl<'a> Parser<'a> { fn read_or(&mut self, parsers: &mut [Box Option + 'static>]) -> Option { for pf in parsers { - match self.read_atomically(|p: &mut Parser| pf(p)) { - Some(r) => return Some(r), - None => {} + if let Some(r) = self.read_atomically(|p: &mut Parser| pf(p)) { + return Some(r); } } None diff --git a/src/libstd/primitive_docs.rs b/src/libstd/primitive_docs.rs index b840e51873e3f..e5819522123c4 100644 --- a/src/libstd/primitive_docs.rs +++ b/src/libstd/primitive_docs.rs @@ -12,6 +12,50 @@ // /// The boolean type. /// +/// The `bool` represents a value, which could only be either `true` or `false`. +/// +/// # Basic usage +/// +/// `bool` implements various traits, such as [`BitAnd`], [`BitOr`], [`Not`], etc., +/// which allow us to perform boolean operations using `&`, `|` and `!`. +/// +/// [`if`] always demands a `bool` value. [`assert!`], being an important macro in testing, +/// checks whether an expression returns `true`. +/// +/// ``` +/// let bool_val = true & false | false; +/// assert!(!bool_val); +/// ``` +/// +/// [`assert!`]: std/macro.assert!.html +/// [`if` conditionals]: ../../book/if.html +/// [`BitAnd`]: ../ops/trait.BitAnd.html +/// [`BitOr`]: ../ops/trait.BitOr.html +/// [`Not`]: ../ops/trait.Not.html +/// +/// # Examples +/// +/// A trivial example of the usage of `bool`, +/// +/// ``` +/// let praise_the_borrow_checker = true; +/// +/// // using the `if` conditional +/// if praise_the_borrow_checker { +/// println!("oh, yeah!"); +/// } else { +/// println!("what?!!"); +/// } +/// +/// // ... or, a match pattern +/// match praise_the_borrow_checker { +/// true => println!("keep praising!"), +/// false => println!("you should praise!"), +/// } +/// ``` +/// +/// Also, since `bool` implements the [`Copy`](../marker/trait.Copy.html) trait, we don't +/// have to worry about the move semantics (just like the integer and float primitives). mod prim_bool { } #[doc(primitive = "char")] @@ -533,4 +577,3 @@ mod prim_isize { } /// *[See also the `std::usize` module](usize/index.html).* /// mod prim_usize { } - diff --git a/src/libstd/sys/windows/thread_local.rs b/src/libstd/sys/windows/thread_local.rs index 6a5c38ed9d0da..59da74b728797 100644 --- a/src/libstd/sys/windows/thread_local.rs +++ b/src/libstd/sys/windows/thread_local.rs @@ -69,9 +69,8 @@ static mut DTORS: *mut Vec<(Key, Dtor)> = ptr::null_mut(); pub unsafe fn create(dtor: Option) -> Key { let key = c::TlsAlloc(); assert!(key != c::TLS_OUT_OF_INDEXES); - match dtor { - Some(f) => register_dtor(key, f), - None => {} + if let Some(f) = dtor { + register_dtor(key, f); } return key; }