Chris Huff wrote in message ...
> > > This shouldn't be too hard, since it is apparently possible to
trick
> > > the parser into allowing this already.
> > what about checking parameters count ?
>
> I'm not sure what you mean.

you said about trick,
you mean this from p.u-p ?
what about overdefined declaration
with different number of parameters ?
this could cause unexpected error
(or expected by me in source code)
I think it should be possible without trick

ABX

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In article <3a0d736f@news.povray.org>, "Wlodzimierz ABX Skiba" 
<abx### [at] abxartpl> wrote:

> >In other words, allowing the function to be called in ordinary scene
> >code...
> 
> yes
> 
> >this should be pretty easy
> 
> I hope

I am thinking something like this, in the Parse_Num_Factor() function in 
express.c:

#include "isosrf.h"

...

    CASE(FUNC_ID_TOKEN)
    {
        DBL result = 0;
        int i=0;
        VECTOR Point;
        FUNCTION * TFunc = NULL;

        Load_Function(TFunc, ((FUNCTION *)Token.Data)->func_name);/*?*/
        
        GET(LEFT_PAREN_TOKEN)
        Parse_Vector(Point);
        GET(RIGHT_PAREN_TOKEN)
        if(TFunc != NULL)
            result = (TFunc->iso_func)(TFunc, Point);
        
        for(i=0; i < *Terms; i++)
            Express[i] = Val;
    }
    END_CASE

I don't know if this will work(it compiles, but it hasn't been tested), 
and I have no idea what Load_Function() does...but it's a start.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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Chris Huff wrote in message ...
>I don't know if this will work(it compiles, but it hasn't been tested),
>and I have no idea what Load_Function() does...but it's a start.


I will check your idea, thanks

ABX

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In article <3a0d7ee9@news.povray.org>, "Wlodzimierz ABX Skiba" 
<abx### [at] abxartpl> wrote:

> you said about trick,
> you mean this from p.u-p ?

The "trick" was something like:
#declare Func = function {1}
#declare Func = function {if(z, Func(x, y, z-1), moof)}


> what about overdefined declaration
> with different number of parameters ?
> this could cause unexpected error
> (or expected by me in source code)

If a function calls itself with the wrong number of parameters, it 
certainly should produce an error...just like any other function call.


> I think it should be possible without trick

Definitely. What I meant was that since it is already possible, it 
shouldn't be very difficult to make it work without that 
double-declaration trick. Maybe just creating a "dummy" function with 
the same name and parameters just before parsing the body of the 
function would work...

This:
#declare Func = function(r) {Func(r-1)}

Would do this:
1: Parse function parameter list
2: Create dummy function: Func = function(r){0}
3: Parse body of function: Func = function(r){Func(r-1)}

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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Chris Huff wrote in message ...
>In article <3a0d736f@news.povray.org>, "Wlodzimierz ABX Skiba"
><abx### [at] abxartpl> wrote:
>> I think that there should be also some max_recursion_level
>> perhaps in global_settings
>
>Probably a good idea, infinite recursion is going to be the most common
>error with recursive functions and hard coded limits are simply annoying
>when you run into them.


It should include an option to allow unlimited recursion for those who know
what they are doing.

Mark

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In article <3a0f905a@news.povray.org>, "Mark Wagner" 
<mar### [at] gtenet> wrote:

> It should include an option to allow unlimited recursion for those 
> who know what they are doing.

Umm, unlimited recursion would take an unlimited amount of time and 
memory, it's better to let a function hit a limit and produce a parse or 
render time error. Even those who know what they are doing would never 
use this option...there is no reason I can see to let this "safety net" 
be removed.

It would be nice if you could adjust the max nesting level of macros too.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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