Benjamin Bannier created MESOS-7124:
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Summary: Replaced monadic type get() functions with operator*
Key: MESOS-7124
URL: https://issues.apache.org/jira/browse/MESOS-7124
Project: Mesos
Issue Type: Improvement
Components: libprocess, stout
Reporter: Benjamin Bannier
In MESOS-2757 we introduced {{T* operator->}} for {{Option}}, {{Future}} and
{{Try}}. This provided a convenient short-hand for existing member functions
{{T* get}} providing identical functionality.
To finalize the work of MESOS-2757 we should replace the existing {{T* get()}}
member functions with functions {{T* operator*}}.
This is desirable as having both {{operator->}} and {{get}} in the code base at
the same time lures developers into using the old-style {{get}} instead of
{{operator->}} where it is not needed, e.g.,
{code}
m.get().fun();
{code}
instead of
{code}
m->fun();
{code}
We still require the functionality of {{get}} to directly access the contained
value, but the current API unnecessarily conflates two (at least from a usage
perspective) unrelated aspects; in these instances, we should use an
{{operator*}} instead,
{code}
void f(const T&);
Try<T> m = ..;
f(*m); // instead of: f(m.get());
{code}
Using {{operator*}} in these instances makes it much less likely that users
would use it in instances when they wanted to call functions of the wrapped
value, i.e.,
{code}
m->fun();
{code}
appears more natural than
{code}
(*m).fun();
{code}
Note that this proposed change is in line with the interface of
{{std::optional}}. Also, {{std::shared_ptr}}'s {{get}} is a useful function and
implements an unrelated interface: it surfaces the wrapped pointer as opposed
to its {{operator*}} which dereferences the wrapped pointer. Similarly, our
current {{get}} also produce values, and are unrelated to {{std::shared_ptr}}'s
{{get}}.
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