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tutorial: Try to fit the early discussion of :: in better

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Brian Anderson 2012-12-20 13:42:13 -08:00
parent cbddd5ed34
commit 30fac74bf3
1 changed files with 8 additions and 12 deletions
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doc/tutorial.md
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@ -128,7 +128,7 @@ we have a file `hello.rs` containing this program:
~~~~
fn main() {
io::println("hello?");
core::io::println("hello?");
}
~~~~
@ -142,8 +142,8 @@ error. If you introduce an error into the program (for example, by changing
an error message like this:
~~~~ {.notrust}
hello.rs:2:4: 2:16 error: unresolved name: io::print_with_unicorns
hello.rs:2 io::print_with_unicorns("hello?");
hello.rs:2:4: 2:16 error: unresolved name: core::io::print_with_unicorns
hello.rs:2 core::io::print_with_unicorns("hello?");
^~~~~~~~~~~~~~~~~~~~~~~
~~~~
@ -180,7 +180,8 @@ JavaScript, C#, or PHP), Rust will feel familiar. Code is arranged
in blocks delineated by curly braces; there are control structures
for branching and looping, like the familiar `if` and `while`; function
calls are written `myfunc(arg1, arg2)`; operators are written the same
and mostly have the same precedence as in C; comments are again like C.
and mostly have the same precedence as in C; comments are again like C;
module names are separated with double-colon, `::`, as with C++.
The main surface difference to be aware of is that the condition at
the head of control structures like `if` and `while` do not require
@ -188,12 +189,12 @@ parentheses, while their bodies *must* be wrapped in
braces. Single-statement, unbraced bodies are not allowed.
~~~~
# fn recalibrate_universe() -> bool { true }
# mod universe { fn recalibrate() -> bool { true } }
fn main() {
/* A simple loop */
loop {
// A tricky calculation
if recalibrate_universe() {
if universe::recalibrate() {
return;
}
}
@ -209,16 +210,11 @@ let hi = "hi";
let mut count = 0;
while count < 10 {
io::println(hi);
core::io::println(fmt!("count: %?", i));
count += 1;
}
~~~~
The name of the function that prints a line of text, `io::println`, is
qualified: it refers to the function named `println` that's defined in the
module `io`. In Rust, a double colon separates parts of a
qualified name. For more details, see the section on [crates](#crates).
Although Rust can almost always infer the types of local variables, you
can specify a variable's type by following it with a colon, then the type
name. Constants, an the other hand, always require a type annotation.