OpenEuphoria

Re: RosettaCode

• Posted by jimcbrown (admin) Jan 26, 2011
• 1889 views

Why does it have to be routine-ids, and not some other token like a c-func-id ?

Ok, ok, it can't be done in Euphoria. At least not Euphoria alone. A bottle of machine code glue is required...

Change the call_func()s in composed_call_back() to call_composition() and pass in compose-ids from the other compose into this compose() and it all works.

To turn only a single routine-id (or compose-id) into a c-func-id, pass NOT_USED as the second id.

include std/dll.e 
include std/machine.e 
 
constant mach = 
{ 
-- 0 
#55, 
-- 1 
#89, #e5, 
-- 3 
#83, #ec, #18, 
-- 6 
#c7, #45, #f4, 
-- 9 
#78, #56, #34, #12, 
-- 13 
#c7, #45, #f8, 
-- 16 
#21, #43, #65, #87, 
-- 20 
#c7, #45, #fc, 
-- 23 
#01, #f0, #01, #f0, 
-- 27 
#83, #ec, #04, 
-- 30 
#ff, #75, #08, 
-- 33 
#ff, #75, #f8, 
-- 36 
#ff, #75, #f4, 
-- 39 
#8b, #45, #fc, 
-- 42 
#ff, #d0, 
-- 44 
#83, #c4, #10, 
-- 47 
#c9, 
-- 48 
#c3 
-- 49 
} 
 
function composed_call_back(integer a, integer b, integer c) 
	return call_func(a, {call_func(b, {c})}) 
end function 
constant composed_call_back_mach = call_back(routine_id("composed_call_back")) 
 
public function compose(integer rid_a, integer rid_b) 
	atom a 
	a = allocate(length(mach)) 
	poke(a, mach) 
	poke4(a + 9, rid_a) 
	poke4(a + 16, rid_b) 
	poke4(a + 23, composed_call_back_mach) 
	return define_c_func("", a, {C_ULONG}, C_ULONG) 
end function 
 
public function identity(object x) 
	return x 
end function 
public constant NOT_USED = routine_id("identity") 
 
-- example code 
function ax(integer i) 
return i + 2 
end function 
 
function bx(integer i) 
return i * 2 
end function 
 
atom zx = compose(routine_id("ax"), routine_id("bx")) 
atom xz = compose(routine_id("bx"), routine_id("ax")) 
 
-- should print 4 
? c_func(zx, {1}) 
 
-- should print 6 
? c_func(xz, {1})