reply_form::reply_form()
{
using cppcms::locale::translate;
author.message(translate("Author"));
comment.message(translate("Comment"));
send.value(translate("Send"));
*this + author + comment + send;
author.limits(1,64);
comment.limits(1,256);
}
In the given constructor definition, someone please explain what this syntax means or its intended use and benefits:
*this + author + comment + send;
To me, it appears as if a concatenation/addition which is done without it being assigned to anything, and thats really confusing me as I am not able to understand its purpose.
I have made good searches on web with the problem, but probably, I am not using the right term to search for it as I do not know what exactly this type of syntax is termed as.
I feel as if its the part of latest C++1x features, but not sure, so not able to find the right book for it. Finally chose stackoverflow for rescue :-)
EDIT:
the Most relevant I could provide is its declaration in header file, which is:
struct reply_form : public cppcms::form {
cppcms::widgets::text author;
cppcms::widgets::textarea comment;
cppcms::widgets::submit send;
reply_form();
};
EDIT2:Revision2 (corrected again after checking comments)
Ok, I was able to traceback the operator+ thing, and found out the way it was overloaded:
inline form &operator + (form &f)
{
add(f);
return *this;
}
So this was the case of operator overloading. Thanks for your answer. I have been recently migrated to C++ and had found some strange things as I had posted in this thread: Explain blank class functions in C++ which appeared to me as multifunction list with blank body, but later I understood it as a syntax and a way of declaring a variable or calling the base class constructor.
Thanks for your answers, it were really helpful and very quick!
Since we don't know what reply_form
is, this question cannot be answered in completion. Your question is more about the program than about C++.
The line *this + author + comment + send;
can have side-effects if reply_form::operator+
has side-effects.
Conventionally, though, it would not (because it doesn't make intuitive sense, as you've discovered). So, either this is a fault in the class's design, or the line should read something like *this += author + comment + send;
.
Most likely is a fluent operator overwritten to add fields to a reply_form
. Eg.
reply_form& reply_form::operator+ (const field& value)
{
this->add_field (value);
return *this;
}
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