Trait nom::lib::std::ops::Try [−][src]
pub trait Try { type Ok; type Error; fn into_result(self) -> Result<Self::Ok, Self::Error>; fn from_error(v: Self::Error) -> Self; fn from_ok(v: Self::Ok) -> Self; }
try_trait
)A trait for customizing the behavior of the ?
operator.
A type implementing Try
is one that has a canonical way to view it
in terms of a success/failure dichotomy. This trait allows both
extracting those success or failure values from an existing instance and
creating a new instance from a success or failure value.
Associated Types
type Ok
try_trait
)The type of this value when viewed as successful.
type Error
try_trait
)The type of this value when viewed as failed.
Required Methods
fn into_result(self) -> Result<Self::Ok, Self::Error>
try_trait
)Applies the "?" operator. A return of Ok(t)
means that the
execution should continue normally, and the result of ?
is the
value t
. A return of Err(e)
means that execution should branch
to the innermost enclosing catch
, or return from the function.
If an Err(e)
result is returned, the value e
will be "wrapped"
in the return type of the enclosing scope (which must itself implement
Try
). Specifically, the value X::from_error(From::from(e))
is returned, where X
is the return type of the enclosing function.
fn from_error(v: Self::Error) -> Self
try_trait
)Wrap an error value to construct the composite result. For example,
Result::Err(x)
and Result::from_error(x)
are equivalent.
fn from_ok(v: Self::Ok) -> Self
try_trait
)Wrap an OK value to construct the composite result. For example,
Result::Ok(x)
and Result::from_ok(x)
are equivalent.