function "attributes"

**Edward Z. Yang** · Jun 7 '07, 02:05 AM

Re: function "attribute s"

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Jon Slaughter wrote:

is there any way to simply add an attribute like feature to a
function/method definition? [snip]

You want the "Strategy" pattern, making the function into an object:

class TestFunction
{
var $probability = 0.234321;
function call() { /* ... */ }
}

$func = new TestFunction();
$func->call();

PHP does not treat anonymous functions as first-class objects, unlike
JavaScript, so some acrobatics are necessary to get this working.

- --
Edward Z. Yang GnuPG: 0x869C48DA
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**Jon Slaughter** · Jun 7 '07, 02:35 AM

Re: function "attribute s"

"Edward Z. Yang" <edwardzyang@th ewritingpot.com wrote in message
news:466767B5.3 090901@thewriti ngpot.com...

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>
Jon Slaughter wrote:

>is there any way to simply add an attribute like feature to a
>function/method definition? [snip]

>
You want the "Strategy" pattern, making the function into an object:
>
class TestFunction
{
var $probability = 0.234321;
function call() { /* ... */ }
}
>
$func = new TestFunction();
$func->call();
>
PHP does not treat anonymous functions as first-class objects, unlike
JavaScript, so some acrobatics are necessary to get this working.

This is more work than I'm looking for unless I can someone "wrap" a
function into a functor.

**Toby A Inkster** · Jun 7 '07, 08:05 AM

Re: function "attribute s"

Edward Z. Yang wrote:

class TestFunction
{
var $probability = 0.234321;
function call() { /* ... */ }
}
>
$func = new TestFunction();
$func->call();

The other possibility is to use a static variable and function. The
example below is PHP5 code -- I have no idea if it's possible to translate
it to PHP4.

class Test
{
public static $probability = 0.234321;

public static function call()
{
$x = self::$probabil ity * 1000000;
$r = rand(0, 1000000);
return ($r<$x);
}
}

// Using the function
$truth = Test::call();

// Retrieving the "attribute"
$prob = Test::$probabil ity;

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 103 days, 14:54.]

URLs in demiblog

Page not found - Tobyinkster

http://tobyinkster.co.uk/blog/2007/05/31/demiblog-urls/

**Erwin Moller** · Jun 7 '07, 09:05 AM

Re: function "attribute s"

Jon Slaughter wrote:

is there any way to simply add an attribute like feature to a
function/method definition?
>
say I create a function like
>
function Test()
{
>
//....
}
>
but I want to assign a probability to it in the definition itself... maybe
something like
>
function Test()
{
static $probability = 0.234321;
//....
}
>
Now is there any way that I can get the probability from the function? I'm
using function pointers to call the functions in a random way. Essentially
having a list of functions that have assigned probabilities and calling
them based on that probability(I don't want to really seperate the
probability from the definition.
>
>
Ultimately it would be nice to extend the syntax to handle a new keyword
like
>
function Test():[Probability=0.1 23421]
{
>
}
>
or something like that but I know thats not going to happen.
>
Thanks,
Jon

Hi Jon,

A simple idea but maybe it works in your situation:
1) Make your function a class.
2) Instantiate one for each function you need. (Function should now be named
method in OOP)
3) Add a simple method that stores name/value pairs you like to add to that
instance, simply storing them in an instancevariabl e hashed array.

class TestFunction{
var $addedValues;
function addValues($name ,$value) {
$addedValues[$name]=$value;
}

function getValues(){
return $addedValues;
}
// rest goes here
}

$test1 = new TestFunction();
$test1->addValues("pro bability",0.234 321);

Is such an approach of any use in your situation?

Regards,
Erwin Moller

**Erwin Moller** · Jun 7 '07, 09:05 AM

Re: function "attribute s"

Erwin Moller wrote:

Jon Slaughter wrote:
>

>is there any way to simply add an attribute like feature to a
>function/method definition?
>>
>say I create a function like
>>
>function Test()
>{
>>
> //....
>}
>>
>but I want to assign a probability to it in the definition itself...
>maybe something like
>>
>function Test()
>{
> static $probability = 0.234321;
> //....
>}
>>
>Now is there any way that I can get the probability from the function?
>I'm using function pointers to call the functions in a random way.
>Essentially having a list of functions that have assigned probabilities
>and calling them based on that probability(I don't want to really
>seperate the probability from the definition.
>>
>>
>Ultimately it would be nice to extend the syntax to handle a new keyword
>like
>>
>function Test():[Probability=0.1 23421]
>{
>>
>}
>>
>or something like that but I know thats not going to happen.
>>
>Thanks,
>Jon

>
Hi Jon,
>
A simple idea but maybe it works in your situation:
1) Make your function a class.
2) Instantiate one for each function you need. (Function should now be
named method in OOP)
3) Add a simple method that stores name/value pairs you like to add to
that instance, simply storing them in an instancevariabl e hashed array.
>
class TestFunction{
var $addedValues;

var $addedValues = array();

is clearer. :-)

function addValues($name ,$value) {
$addedValues[$name]=$value;
}
>
function getValues(){
return $addedValues;
}
// rest goes here
}
>
$test1 = new TestFunction();
$test1->addValues("pro bability",0.234 321);
>
>
Is such an approach of any use in your situation?
>
Regards,
Erwin Moller

**Jon Slaughter** · Jun 7 '07, 03:25 PM

Re: function "attribute s"

"Erwin Moller"
<since_humans_r ead_this_I_am_s pammed_too_much @spamyourself.c omwrote in
message news:4667c82f$0 $336$e4fe514c@n ews.xs4all.nl.. .

Jon Slaughter wrote:
>

>is there any way to simply add an attribute like feature to a
>function/method definition?
>>
>say I create a function like
>>
>function Test()
>{
>>
> //....
>}
>>
>but I want to assign a probability to it in the definition itself...
>maybe
>something like
>>
>function Test()
>{
> static $probability = 0.234321;
> //....
>}
>>
>Now is there any way that I can get the probability from the function?
>I'm
>using function pointers to call the functions in a random way.
>Essentially
>having a list of functions that have assigned probabilities and calling
>them based on that probability(I don't want to really seperate the
>probability from the definition.
>>
>>
>Ultimately it would be nice to extend the syntax to handle a new keyword
>like
>>
>function Test():[Probability=0.1 23421]
>{
>>
>}
>>
>or something like that but I know thats not going to happen.
>>
>Thanks,
>Jon

>
Hi Jon,
>
A simple idea but maybe it works in your situation:
1) Make your function a class.
2) Instantiate one for each function you need. (Function should now be
named
method in OOP)
3) Add a simple method that stores name/value pairs you like to add to
that
instance, simply storing them in an instancevariabl e hashed array.
>
class TestFunction{
var $addedValues;
function addValues($name ,$value) {
$addedValues[$name]=$value;
}
>
function getValues(){
return $addedValues;
}
// rest goes here
}
>
$test1 = new TestFunction();
$test1->addValues("pro bability",0.234 321);
>
>
Is such an approach of any use in your situation?
>
>

Its not that I can't use it but I feel that its to much "work". It defeats
the purpose ot trying to make it easier. Essentially I would have to wrap
all the functions into functors for just one attribute. Essentially what I
need is a way to add meta data. I think Toby's method might work.

Thanks,
Jon

**Jon Slaughter** · Jun 7 '07, 03:35 PM

Re: function "attribute s"

"Toby A Inkster" <usenet200705@t obyinkster.co.u kwrote in message
news:uunkj4-h76.ln1@ophelia .g5n.co.uk...

Edward Z. Yang wrote:
>

>class TestFunction
>{
> var $probability = 0.234321;
> function call() { /* ... */ }
>}
>>
>$func = new TestFunction();
>$func->call();

>
The other possibility is to use a static variable and function. The
example below is PHP5 code -- I have no idea if it's possible to translate
it to PHP4.
>

class Test
{
public static $probability = 0.234321;
>
public static function call()
{
$x = self::$probabil ity * 1000000;
$r = rand(0, 1000000);
return ($r<$x);
}
}
>
// Using the function
$truth = Test::call();
>
// Retrieving the "attribute"
$prob = Test::$probabil ity;
>

So I have to call the function first? ;/ Isn't going to work ;/ I have to
get the probabilities from the function to determine which function to call
;/
Ultimately it seems I'm going to have to use functors or just write a method
to add the functions that takes a pointer but just seems a little overkill
just to add one "attribute" .

thanks,
Jon

**Aerik** · Jun 7 '07, 04:35 PM

Re: function "attribute s"

Jon,

What are you trying to accomplish? Do you have a list of functions,
and you want to call each one if the probability of it being called is
above a certain threshold? If so, a very simple approach might be to
assign the probabilities and functions to an array.

See if this is what you're trying to do, or perhaps clarify it to me/
us:

$funcary[] = array('probabil ity'=>.75, 'funcname'=>'fu nction1');
$funcary[] = array('probabil ity'=>.47, 'funcname'=>'fu nction2');
$funcary[] = array('probabil ity'=>.99, 'funcname'=>'fu nction3');

$curprob = rand(0,100)/100;

foreach($funcar y as $afunc=>$ary){
if ($afunc['probability'] < $curprob) $afunc['funcname']();
}

Where 'function1' etc. are the names of your functions. I didn't test
this at all, fyi, but I think it should work.

Aerik

**Jon Slaughter** · Jun 7 '07, 05:25 PM

Re: function "attribute s"

"Aerik" <asylvan@gmail. comwrote in message
news:1181233787 .529402.108340@ i38g2000prf.goo glegroups.com.. .

Jon,
>
What are you trying to accomplish? Do you have a list of functions,
and you want to call each one if the probability of it being called is
above a certain threshold? If so, a very simple approach might be to
assign the probabilities and functions to an array.
>
See if this is what you're trying to do, or perhaps clarify it to me/
us:
>
$funcary[] = array('probabil ity'=>.75, 'funcname'=>'fu nction1');
$funcary[] = array('probabil ity'=>.47, 'funcname'=>'fu nction2');
$funcary[] = array('probabil ity'=>.99, 'funcname'=>'fu nction3');
>
$curprob = rand(0,100)/100;
>
foreach($funcar y as $afunc=>$ary){
if ($afunc['probability'] < $curprob) $afunc['funcname']();
}
>
Where 'function1' etc. are the names of your functions. I didn't test
this at all, fyi, but I think it should work.
>
Aerik
>

No, that is my application but what I'm trying to do is in some way assign
the probability to the function that is inline with the function definition.
If, say, I have to create 100 of these functions then then I want to
minimize the amount of excess code just to add the probability part.

I can automatically include the functions because they are in a class and I
use get_class_metho ds to get them... but this just gives me the functions
and in not the probabilities.

For your method you have to know the function name and you have to add them
to the array manually. With my method I do it automatically but I cannot
easily handle the probabilities. (right now I just use 1 as default so I can
get on with the other parts.

If there was some other function such as get_function_at tributes for
example, or get_function_va rs which returns the variables used in a
function(or static vars) then I could extract the probabilities
automatically. Of course there isn't anything like this.

I suppose I could open up the file as a text file and parse it myself but
this is more work that I'd rather not do unless someone as an easy way and
it also seems kinda inefficient.

Jon

**Toby A Inkster** · Jun 7 '07, 06:05 PM

Re: function "attribute s"

Jon Slaughter wrote:

So I have to call the function first?

No. Equally, this would work:

if (Test::$probabi lity < 0.5)
{
$truth = Test::call();
}

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 104 days, 1:37.]

URLs in demiblog

Page not found - Tobyinkster

http://tobyinkster.co.uk/blog/2007/05/31/demiblog-urls/

**Edward Z. Yang** · Jun 8 '07, 12:05 AM

Re: function "attribute s"

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Jon Slaughter wrote:

This is more work than I'm looking for unless I can someone "wrap" a
function into a functor.

It is, however, the cleanest way of implementing it in PHP. Otherwise,
you'll have to use static data or globals.

- --
Edward Z. Yang GnuPG: 0x869C48DA
HTML Purifier <htmlpurifier.o rg Anti-XSS HTML Filter
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**Norman Peelman** · Jun 8 '07, 12:45 AM

Re: function "attribute s"

Jon Slaughter wrote:

is there any way to simply add an attribute like feature to a
function/method definition?
>
say I create a function like
>
function Test()
{
>
//....
}
>
but I want to assign a probability to it in the definition itself... maybe
something like
>
function Test()
{
static $probability = 0.234321;
//....
}
>
Now is there any way that I can get the probability from the function? I'm
using function pointers to call the functions in a random way. Essentially
having a list of functions that have assigned probabilities and calling them
based on that probability(I don't want to really seperate the probability
from the definition.
>
>
Ultimately it would be nice to extend the syntax to handle a new keyword
like
>
function Test():[Probability=0.1 23421]
{
>
}
>
or something like that but I know thats not going to happen.
>
Thanks,
Jon
>
>

Ok, this is ugly but if you name your functions by their probability:

function _0_234321()
{ // test function
$probability = 0.234321;
echo "$probability<b r>";
...
}
$probability = 0.234321;
$func_to_call = '_'.str_replace ('.','_',$proba bility);
//echo $func_to_call.' <br>';
call_user_func( $func_to_call);

.... or am I missing the point?

Norm