On 3/7/2016 12:15 AM, Paul Fultz II wrote:
>
>
> On Sunday, March 6, 2016 at 9:42:19 PM UTC-6, Edward Diener wrote:
>>
>> On 3/3/2016 6:43 AM, Vicente J. Botet Escriba wrote:
>>> Dear Boost community, sorry for the late anounce
>>>
>>> The formal review of Paul Fultz II's Fit library starts today, 2nd March
>>> and ends on 13th March.
>>>
>>> Fit is a header-only C++11/C++14 library that provides utilities for
>>> functions and function objects.
>>
>> These are some comments/queries about the Fit documentation.
>>
>> Introduction
>>
>> The introduction says that Fit "provides utilities for functions and
>> function objects." But it seems as if Fit works only with lambda
>> functions and function objects.
>
>
> Fit works with any generalized Callable:
>
> http://en.cppreference.com/w/cpp/concept/Callable

Please document this. A generalized Callable is a much bigger set of
functionality than just lambda functions and function objects.

>
>
>> The term 'function' normally encompasses
>> a much larger definition in C++ which includes global functions, static
>> functions, member functions, and lambda functions.
>
>
> Which is what Callable encompasses, but I used "function" since more
> people are familiar with that than Callable.

A 'function' and a Callable in C++ are two entirely different things.
Use the one that is precise and don't worry what people are familiar
with. Explain what a Callable is early on ( I know you explain it later
) if you feel that people do not know what it means.

>
>
>> Fit needs to be more
>> precise in what it says it works with. It repeatedly refers to function
>> objects and lambda functions as 'functions'. I think this vagueness of
>> terminality is really confusing in the documentation.
>>
>
> Perhaps, I should refer to the Callable concept early on then.

See above.

>
>
>>
>> Quick Start:Function Objects
>>
>> "We can make it behave like a regular function if we construct the class
>> as a global variable."
>>
>> What about a non-global
>>
>> sum_f sum = sum_f();
>>
>> makes 'sum' not behave like a regular function other than the fact that
>> the variable 'sum' may eventually go out of scope ?
>>
>
> In C++, a regular function is always global, there is no such thing as local
> function(sans gcc extensions).

My point is that the non-global 'sum' in my example above behaves just
as much like a regular function as your global 'sum'. You may want to
promote the idea of global function objects but I think that this is
personally a bad idea. IMO global variables of any kind are to be avoided.

>
>
>>
>> Quick Start:Lambdas
>>
>> Why do we need both BOOST_FIT_STATIC_LAMBDA and
>> BOOST_FIT_STATIC_LAMBDA_FUNCTION ? I would seem that
>> BOOST_FIT_STATIC_LAMBDA_FUNCTION would be adequate and
>> BOOST_FIT_STATIC_LAMBDA is just redundant, mimicking lambda syntax to no
>> purpose.
>>
>
> BOOST_FIT_STATIC_LAMBDA_FUNCTION and BOOST_FIT_STATIC_FUNCTION both define a
> function at global scope, and can only be used at global scope, whereas
> BOOST_FIT_STATIC_LAMBDA can be used to constexpr initialize local variables
> as
> well.

It might be good to add that when the end-user first encounters
BOOST_FIT_STATIC_LAMBDA, because the name does not suggest
initialization of local objects. Furthermore I cannot imagine why one
would want to use it to initialize a local object,

so you might want to
explain the benefit of doing so as opposed to the normal syntax for
creating a lambda function.

> In fact, BOOST_FIT_LIFT uses this since it is not always clear what
> context the user might call BOOST_FIT_LIFT.
>
>
>>
>> Quick Start:Overloading
>>
>> The overloading adaptors show two or more lambda functions. Can they
>> also work with function objects ? Or a mix of lambda functions and
>> function objects ? In fact all the reamining Quick Start topics show
>> examples with lambda functions. Do they also work with function objects ?
>>
>
> Yes it can be used with function objects. I probably should show an example
> of
> that as well. I used the lambdas because of the terseness of them.

Evidently the adaptors can be used with any Callable. I think you should
make that point very strongly and show that in examples also.

>
>
>>
>> Quick Start:Variadic
>>
>> I do not understand what 'We can also make this print function varidiac,
>> so it prints every argument passed into it.' means ?
>>
>
> I'll try to explain that better, but basically it will print each argument,
> so:
>
> print("hello", 5); // Will print "hello" and 5

I wouldn't associate that with the word 'Variadic' but I do think you
need to explain that more clearly.

>
>
>>
>> I do not think the Quick Start explains very much since it is dealing
>> with adaptors of which we know almost nothing and the explanation for
>> these adaptors and what they actually do is very terse.
>
>
> Probably can expand the explanation of adaptors a little more.

Good idea. What do adaptors create ?

Different function objects I would
imagine ? In that case how about the explanation that adaptors take
Callables as input and generate function object types that adapt the
original functionality of one or more Callables to some other purpose.

>
>
>>
>> In the 'Signatures' section of the Overview I read:
>>
>> "All the functions are global function objects except where an explicit
>> template parameter is required." I honestly don't know what this is
>> supposed to mean. Does this refer to when function objects are referred
>> to as parameters to the adaptors, functions, and utilities of the library
>> ?
>>
>
> I don't understand what you are asking. It means that the function is
> written
> like this in the documentation:
>
> template<class IntegralConstant>
> constexpr auto if_(IntegralConstant);
>
> But its actually a function object like this in the code:
>
> struct if_f
> {
>      template<class IntegralConstant>
>      constexpr auto operator()(IntegralConstant) const;
> };
> const constexpr if_f if_ = {};
>
> However, `if_c` is written like this in the documentation:
>
> template<bool B, class F>
> constexpr auto if_c(F);
>
> It requires the bool `B` template parameter explicity. So in the code it is
> written as a function and not as a function object.

I don't understand to what you are referring when you say 'function'.
Are you talking about adaptors in your library, functions in your
library, or what ?

Please try to understand that your use of the word
'function' is very broad but that the word 'function' in C++ has a much
narrower meaning.