docs: Explain underscore prefix in tutorial

This commit is contained in:
Brian Anderson 2012-10-04 14:44:19 -07:00
parent 096bcd59b8
commit e3f458e639

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@ -240,8 +240,13 @@ let monster_size: int = 50;
~~~~ ~~~~
Local variables may shadow earlier declarations, as in the previous Local variables may shadow earlier declarations, as in the previous
example in which `my_favorite_value` is first declared as a `float` example in which `monster_size` is first declared as a `float`
then a second `my_favorite_value` is declared as an int. then a second `monster_size` is declared as an int. If you were to actually
compile this example though, the compiler will see that the second
`monster_size` is unused, assume that you have made a mistake, and issue
a warning. For occasions where unused variables are intentional, their
name may be prefixed with an underscore to silence the warning, like
`let _monster_size = 50;`.
Rust identifiers follow the same rules as C; they start with an alphabetic Rust identifiers follow the same rules as C; they start with an alphabetic
character or an underscore, and after that may contain any sequence of character or an underscore, and after that may contain any sequence of