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tutorial: Simplify the first example. Misc

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Brian Anderson 2012-09-22 23:11:24 -07:00
parent 3b89dcbdf2
commit 2e7ddee823
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doc/tutorial.md
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@ -204,16 +204,13 @@ paretheses, while their bodies *must* be wrapped in
brackets. Single-statement, bracket-less bodies are not allowed.
~~~~
# fn calibrate_universe() -> bool { false }
# fn party_on() {}
# fn panic() {}
# fn recalibrate_universe() -> bool { true }
fn main() {
while calibrate_universe() {
/* Ensure that basic math still operates is expected */
if 2*20 > 30 {
party_on(); // That's a relief
} else {
panic();
/* A simple loop */
loop {
// A tricky calculation
if recalibrate_universe() {
return;
}
}
}
@ -438,10 +435,9 @@ The nil literal is written just like the type: `()`. The keywords
Character literals are written between single quotes, as in `'x'`. Just as in
C, Rust understands a number of character escapes, using the backslash
character, `\n`, `\r`, and `\t` being the most common.
String literals allow the same escape sequences. They are written
between double quotes (`"hello"`). Rust strings may contain newlines.
character, `\n`, `\r`, and `\t` being the most common. String literals,
written between double quotes, allow the same escape sequences. Rust strings
may contain newlines.
## Operators
@ -482,14 +478,19 @@ a syntax extension is being used, the names of all syntax extensions end with
which is `fmt!`, a `sprintf`-style text formatter that is expanded at compile
time.
~~~~
io::println(fmt!("%s is %d", ~"the answer", 42));
~~~~
`fmt!` supports most of the directives that [printf][pf] supports, but
will give you a compile-time error when the types of the directives
don't match the types of the arguments.
~~~~
# let mystery_object = ();
io::println(fmt!("%s is %d", "the answer", 43));
// %? will conveniently print any type
io::println(fmt!("what is this thing: %?", mystery_object));
~~~~
[pf]: http://en.cppreference.com/w/cpp/io/c/fprintf
You can define your own syntax extensions with the macro system, which is out
@ -505,11 +506,11 @@ compulsory, an optional `else` clause can be appended, and multiple
~~~~
if false {
io::println(~"that's odd");
io::println("that's odd");
} else if true {
io::println(~"right");
io::println("right");
} else {
io::println(~"neither true nor false");
io::println("neither true nor false");
}
~~~~