Font-lock assumes C++ variables instantiated via ctor are functio ns

[Marshall, Simon]

I'm fairly sure this never made it to the lists, so here it is again...
I'm not on either mailing list, so plz include me directly if you have
questions.

-----Original Message-----
From: Marshall, Simon 
Sent: 16 August 2006 18:30
To: 'address@hidden'
Cc: 'Emacs Pretest Bug (address@hidden)'
Subject: Font-lock assumes C++ variables instantiated via ctor are functions

Consider this C++ code:

class Fubar {   // Fubar as type - OK
  Fubar();              // Fubar as function - OK
  Fubar a;              // a as variable - OK
  Fubar b();    // b as function - OK
  Fubar c(A);   // c as function - OK
};

Fubar f;                // f as variable - OK
Fubar g();              // y as function - OK
Fubar h(f);             // z as function - probably OK really

int fubar()
{
  Fubar x;              // x as variable - OK
  Fubar y();    // y as function - OK
  Fubar z(X);   // z as function - not OK
}

In Emacs 21, assuming you had added "Fubar" to c++-font-lock-extra-types, y
and z would be fontified as variables, on the basis that declaring functions
locally (as for y) is not common whereas z is almost certainly a variable
and is very common.  In other words, it usually does the right thing.
(Emacs 21 fontified y/z differently, IIRC by virtue of them being within a
block but not being part of a class declaration.)

In the current Emacs 22 from CVS, you don't have to add to
c++-font-lock-extra-types, which is great.  However, y and z are fontified
as functions.  In other words, it usually does the wrong thing.

Obviously, it's very difficult to get this right without writing a C++
parser.  It really isn't clear what is the best thing to do for h, since it
really could be either a function or a variable declaration (you would have
to pick apart the parameters and consult the gods).  But z is almost
certainly going to be a variable declaration and this style of variable
instantiation is obviously very common.

I'm off on holiday, so let the flame fest begin!  Simon.