Re: Thin delegate adapter
On Thu, Jan 13, 2011 at 5:30 AM, Dmitry Olshansky dmitry.o...@gmail.comwrote:
On 13.01.2011 2:16, Guilherme Vieira wrote:
No sh*t..?! @__@ That's so cool! But is it smart enough to know the stack
frame doesn't need to go to heap in this case? (since it returns a heap
object referecing another heap object, i.e. can it untangle `b' from the
stack?)
Ehm, it can optimize certain cases but for the moment it doesn't.
Still, it needs to store b somewhere, right? and delegate is 2 pointers in
fact, so b should go on heap anyway. So it narrows down to if it can save
only parts of the stack frame ...
Since it only uses something the size of a pointer (`b'), it might as well
do some trickery and use `b' as `this' and turn the delegate into (Switch.State
state) { this.toggled = cast(bool)(state); } (or something of similar
effect).
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
Thin delegate adapter
Hi,
I'm wondering if a delegate adapter template like isn't handy for Phobos (it
may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State.OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a), Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support multiple
arguments. I also wanted to place the argument type tuple somwhere else
(actually wanted to hide it completely, but I think that's not possible).
Feedback?
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
Re: Thin delegate adapter
On Wed, Jan 12, 2011 at 10:41 AM, Guilherme Vieira n2.nitro...@gmail.comwrote:
Hi,
I'm wondering if a delegate adapter template like isn't handy for Phobos
(it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State.OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a), Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support multiple
arguments. I also wanted to place the argument type tuple somwhere else
(actually wanted to hide it completely, but I think that's not possible).
Feedback?
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
Oops, missed the template itself:
template adapt(alias fun, Arg)
{
auto adapt(Object)(Object obj)
{
auto adaptImpl = new AdaptImpl!(fun, Object)(obj);
return adaptImpl.opCall!(Arg);
}
}
class AdaptImpl(alias fun, Object)
{
this(Object obj) { this.obj = obj; }
auto opCall(Arg)(Arg a) { return binaryFun!(fun, a, obj)(a, obj); }
private Object obj;
}
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
Re: Thin delegate adapter
On 12.01.2011 15:41, Guilherme Vieira wrote:
Hi,
I'm wondering if a delegate adapter template like isn't handy for
Phobos (it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State..OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a), Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support
multiple arguments. I also wanted to place the argument type tuple
somwhere else (actually wanted to hide it completely, but I think
that's not possible).
Feedback?
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
How is it better then built-in language feature? This works just fine:
void main()
{
//they can't be scope and compiler enforces this (+ scope is deprecated)
//actually, the orignal code is unsafe - what hapens if adapted delegate
escapes current scope?
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State a){ b.toggled = cast(bool)a; };
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
--
Dmitry Olshansky
Re: Thin delegate adapter
Ah, I totally missed that. But what if `s' went out of the scope and the
scope ended? Wouldn't the scope reference (the one containing `b') be lost
and cause memory corruption?
E.g.:
Switch make_switch()
{
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State state) { b.toggled = cast(bool)(state); };
return s;
}
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 10:57 AM, Dmitry Olshansky dmitry.o...@gmail.comwrote:
On 12.01.2011 15:41, Guilherme Vieira wrote:
Hi,
I'm wondering if a delegate adapter template like isn't handy for Phobos
(it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State..OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a), Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support multiple
arguments. I also wanted to place the argument type tuple somwhere else
(actually wanted to hide it completely, but I think that's not possible).
Feedback?
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
How is it better then built-in language feature? This works just fine:
void main()
{
//they can't be scope and compiler enforces this (+ scope is deprecated)
//actually, the orignal code is unsafe - what hapens if adapted delegate
escapes current scope?
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State a){ b.toggled = cast(bool)a; };
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
--
Dmitry Olshansky
Re: Thin delegate adapter
On 12.01.2011 16:07, Guilherme Vieira wrote:
Ah, I totally missed that. But what if `s' went out of the scope and
the scope ended? Wouldn't the scope reference (the one containing `b')
be lost and cause memory corruption?
E.g.:
Switch make_switch()
{
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State state) { b.toggled = cast(bool)(state); };
return s;
}
That's the main point of built-in delegates - the compiler detects them
and places the enclosing stack frame on heap, so it's all sort of cool
magic that just works :)
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 10:57 AM, Dmitry Olshansky
dmitry.o...@gmail.com mailto:dmitry.o...@gmail.com wrote:
On 12.01.2011 15:41, Guilherme Vieira wrote:
Hi,
I'm wondering if a delegate adapter template like isn't handy
for Phobos (it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State..OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a),
Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support
multiple arguments. I also wanted to place the argument type
tuple somwhere else (actually wanted to hide it completely,
but I think that's not possible).
Feedback?
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
How is it better then built-in language feature? This works just fine:
void main()
{
//they can't be scope and compiler enforces this (+ scope is
deprecated)
//actually, the orignal code is unsafe - what hapens if adapted
delegate escapes current scope?
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State a){ b.toggled = cast(bool)a; };
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
--
Dmitry Olshansky
--
Dmitry Olshansky
Re: Thin delegate adapter
No sh*t..?! @__@ That's so cool! But is it smart enough to know the stack
frame doesn't need to go to heap in this case? (since it returns a heap
object referecing another heap object, i.e. can it untangle `b' from the
stack?)
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 11:49 AM, Dmitry Olshansky dmitry.o...@gmail.comwrote:
On 12.01.2011 16:07, Guilherme Vieira wrote:
Ah, I totally missed that. But what if `s' went out of the scope and the
scope ended? Wouldn't the scope reference (the one containing `b') be lost
and cause memory corruption?
E.g.:
Switch make_switch()
{
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State state) { b.toggled = cast(bool)(state); };
return s;
}
That's the main point of built-in delegates - the compiler detects them
and places the enclosing stack frame on heap, so it's all sort of cool magic
that just works :)
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 10:57 AM, Dmitry Olshansky
dmitry.o...@gmail.commailto:
dmitry.o...@gmail.com wrote:
On 12.01.2011 15:41, Guilherme Vieira wrote:
Hi,
I'm wondering if a delegate adapter template like isn't handy
for Phobos (it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State..OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a),
Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't support
multiple arguments. I also wanted to place the argument type
tuple somwhere else (actually wanted to hide it completely,
but I think that's not possible).
Feedback?
-- Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
How is it better then built-in language feature? This works just fine:
void main()
{
//they can't be scope and compiler enforces this (+ scope is
deprecated)
//actually, the orignal code is unsafe - what hapens if adapted
delegate escapes current scope?
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State a){ b.toggled = cast(bool)a; };
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
-- Dmitry Olshansky
--
Dmitry Olshansky
Re: Thin delegate adapter
On 13.01.2011 2:16, Guilherme Vieira wrote:
No sh*t..?! @__@ That's so cool! But is it smart enough to know the
stack frame doesn't need to go to heap in this case? (since it returns
a heap object referecing another heap object, i.e. can it untangle `b'
from the stack?)
Ehm, it can optimize certain cases but for the moment it doesn't.
Still, it needs to store b somewhere, right? and delegate is 2 pointers
in fact, so b should go on heap anyway. So it narrows down to if it can
save only parts of the stack frame ...
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 11:49 AM, Dmitry Olshansky
dmitry.o...@gmail.com mailto:dmitry.o...@gmail.com wrote:
On 12.01.2011 16:07, Guilherme Vieira wrote:
Ah, I totally missed that. But what if `s' went out of the
scope and the scope ended? Wouldn't the scope reference (the
one containing `b') be lost and cause memory corruption?
E.g.:
Switch make_switch()
{
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State state) { b.toggled =
cast(bool)(state); };
return s;
}
That's the main point of built-in delegates - the compiler detects
them and places the enclosing stack frame on heap, so it's all
sort of cool magic that just works :)
--
Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
On Wed, Jan 12, 2011 at 10:57 AM, Dmitry Olshansky
dmitry.o...@gmail.com mailto:dmitry.o...@gmail.com
mailto:dmitry.o...@gmail.com mailto:dmitry.o...@gmail.com
wrote:
On 12.01.2011 15:41, Guilherme Vieira wrote:
Hi,
I'm wondering if a delegate adapter template like isn't
handy
for Phobos (it may be especially useful for std.signal):
class Switch
{
enum State { ON, OFF }
void trigger()
{
switch (mState)
{
case State.ON: mState = State..OFF; break;
case State.OFF: mState = State.ON; break;
default: break;
}
if (watch !is null) watch(mState);
}
void delegate(State s) watch;
private State mState;
}
class ToggleButton
{
@property toggled(bool toggled)
{
writeln(ToggleButton.toggled(, toggled, ));
}
}
void main()
{
scope s = new Switch();
scope b = new ToggleButton();
s.watch = b.toggled; // error: invalid conversion
s.watch = adapt!(obj.toggled = cast(bool)(a),
Switch.State)(b);
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
Yes, it urges to be polished. Particularly, it doesn't
support
multiple arguments. I also wanted to place the argument
type
tuple somwhere else (actually wanted to hide it completely,
but I think that's not possible).
Feedback?
-- Atenciosamente / Sincerely,
Guilherme (n2liquid) Vieira
How is it better then built-in language feature? This works
just fine:
void main()
{
//they can't be scope and compiler enforces this (+ scope is
deprecated)
//actually, the orignal code is unsafe - what hapens if adapted
delegate escapes current scope?
auto s = new Switch();
auto b = new ToggleButton();
s.watch = (Switch.State a){ b.toggled = cast(bool)a; };
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
s.trigger(); // prints `ToggleButton.toggled(true)`
s.trigger(); // prints `ToggleButton.toggled(false)`
}
-- Dmitry Olshansky
--
Dmitry Olshansky
--
Dmitry Olshansky
