This crate provides the if_chain! macro -- a macro for composing
long chains of if-else if-else statements.
It is intended to provide an alternative to writing if chains with match,
such as:
rust
match () {
_ if some_condition => ...,
_ if some_other_condition => ...,
_ if some_third_condition => ...,
_ => ...,
}
While it is mainly intended for long chains, if_chain! can be used
for simple if-else situations, such as:
rust
if_chain! {
| some_condition => (/* some_condition is true */),
| _ => (/* the else branch */)
}
The earlier match example can be rewritten as:
rust
if_chain! {
| some_condition => ...,
| some_other_condition => ...,
| some_third_condition => ...,
}
Note that the else branch is not required, since if_chain! simply gets
expanded into:
rust
if some_condition {
...
} else if some_other_condition }
...
} else if some_third_condition {
...
}