Convenience methods wrap up existing functionality in a more convenient way. The work done by a convenience method varies widely:
std::path::Path`std::path::Pathtype provides methods like` type
provides methods like stat`staton` on Path`Paths that simply invoke the corresponding function in`s that simply invoke the corresponding
function in std::io::fs`std::io::fs`.str`strtype provides a` type provides a
.len()`.len()convenience method which is also expressible as` convenience method which is also expressible as .as_bytes().len()`.as_bytes().len(). Sometimes the conversion is more complex: the`.
Sometimes the conversion is more complex: the str`strmodule also provides` module also provides
from_chars`from_chars`, which encapsulates a simple use of iterators.&str`&strs provide a`s
provide a connect`connectas well as a special case,` as well as a special case, concat`concat, that is expressible using`, that is expressible
using connect`connectwith a fixed separator of` with a fixed separator of ""`""`.Providing more efficient special cases. The connect`connectand` and concat`concatexample also applies here: singling out` example
also applies here: singling out concat`concat` as a special case allows for a more
efficient implementation.
Note, however, that the connect`connectmethod actually detects the special case internally and invokes` method actually detects the special case
internally and invokes concat`concat`. Usually, it is not necessary to add a public
convenience method just for efficiency gains; there should also be a
conceptual reason to add it, e.g. because it is such a common special case.
It is tempting to add convenience methods in a one-off, haphazard way as common use patterns emerge. Avoid this temptation, and instead design small, coherent sets of convenience methods that are easy to remember:
_str`_strvariants of methods that provide a` variants of methods that provide a str`stroutput, instead ensure that the normal output type of methods is easily convertible to` output,
instead ensure that the normal output type of methods is easily convertible to
str`str`.Path`PathAPI mentioned above includes a small selection of the most common filesystem operations that take a` API mentioned above includes a small
selection of the most common filesystem operations that take a Path`Path`
argument. If one convenience method strongly suggests the existence of others,
consider adding the whole group.