Re: FYI: line nums in C++

[Paul Eggert]

Akim Demaille <address@hidden> writes:

> > unsigned int l_ = rline_[n_];
> > YYCDEBUG << "Reducing via rule " << n_ - 1 << " (line " << l_ << "), ";
> 
> Well, I am not convinced that this is more readable.  In particular
> the cast here does look like a function call, and this functional
> style is more readable to my eyes than something more imperative.

It's no more imperative than the other style, as it merely gives a
name to a subexpression.  That is commonly done even in purely
functional languages.

In C, another advantage of using the named subexpression is that it's
more likely to catch a programming error.  If rline_[n_] happened to
be of pointer type, the above code must cause the compiler to generate
a diagnostic; this is not true of the static cast.  The problem is
that casts are too strong; they convert too many different types to
the result type.  Initializers are weaker, and are thus more likely to
catch coding errors.  I suspect that similar results hold for C++.

It's no big deal, of course.