After quite some hacking and hours of fiddling around I
got this to run:
////////////////////////////
var s = ("Some", "Strings","to","be","sorted");
var vs = varray[string] s;
println "Hello";
println s;
println vs;
// Given a Felix comparator, we need to make an STL compliant one
// This is very hard because the felix one takes a tuple
// and the C++ one requires separate arguments
header
"""
template<class CT, class FT2, class FFT>
struct comparator {
FFT cmp;
comparator() : cmp(0) {}
comparator(FFT cmp_a) : cmp(cmp_a) {}
bool operator ()(CT x, CT y){
pair<CT,CT> z(x,y);
return cmp->apply(*(FT2*)(void*)&z);
}
};
""" requires header "#include <utility>";
type _comparator[CT,FT2,FFT] = "comparator<?1,?2,?3>";
typedef comparator[T] = _comparator[T,T*T,T*T->bool];
fun _make_comparator[CT,FT2,FFT]: FFT -> comparator[CT] =
"comparator<?1,?2,?3>($1)";
fun make_comparator[T](cmp:T * T -> bool) => _make_comparator[T, T*T,
T*T->bool] (cmp);
// invoke stl sort
proc _sort[T]: comparator[T] * &T * &T = "std::sort($2, $3, $1);"
requires header "#include <algorithm>";
// in place sort of varray using STL sort
proc sort[t] (cmp: t * t -> bool) (a:varray[t]) {
var first = a.stl_begin;
var last = a.stl_end;
println$ "Array from " + str (C_hack::_ctor_address first) + " to " + str
(C_hack::_ctor_address last);
var z: comparator[t] = make_comparator[t] (cmp);
_sort[t] (z,first,last);
}
sort (eq of (string * string)) (vs);
println vs;
/////////////////////////////
This is a prototype for the library function Varray::sort.
Imagine my dismay when it printed:
Hello
('Some', 'Strings', 'to', 'be', 'sorted')
varray('Some', 'Strings', 'to', 'be', 'sorted')
Array from 1049472 to 1049512
varray('Some', 'Strings', 'to', 'be', 'sorted')
Like, everything worked but it didn't sort the array! Anyone see the bug?
[Hint: there's nothing wrong with the binding code .. :]
BTW: most of the messing about you see is because Felix functions
are C++ classes with an apply() method taking a single argument,
which in this case is a tuple. Since I just happen to know this is layout
compatible with any struct with the same member types, I used the
STL pair<> template in C++ to make a pair and used a cast:
pair<CT,CT> z(x,y);
return cmp->apply(*(FT2*)(void*)&z);
to call the Felix function. The variable z is there just so we can take its
address so we can "reinterpret" it via a void*, since (stupidly) in C++
you can't take the address of an rvalue. A reinterpret<> cast can't do
that either. [Yes, it is stupid because there is a one line workaround,
which is used in Felix, look at reinterpret<> in
http://184.106.135.43:1234/lib/rtl/flx_meta.hpp
Oh, BTW, if you're wonder why I'm working on a sort, well look at:
http://184.106.135.43:1234/lib/rtl
Yeah. In OSX that directory listing is alphabetical, on Ubuntu 10.5LTS it isn't.
So I'magunnasortitforya.
--
john skaller
skal...@users.sourceforge.net
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