[PD] constants

[Martin Peach]

On 2012-02-16 13:39, Mathieu Bouchard wrote:
> Le 2012-02-15 à 13:11:00, Jonathan Wilkes a écrit :
>
>> Instead of time units, let's take the incoming single-selector "pi"
>> and replace it with the float value of pi for any object that doesn't
>> have a "pi" method or an "anything" method (but does have a float
>> method).  Furthermore, if a class defines a float argument but the
>> argument provided isn't a float, then check first if what it received
>> was A_SYMBOL 'pi' and if so replace with the float value of pi. Is
>> what I wrote above possible to do without causing huge problems to
>> performance or creating ambiguities?
>
> Compared to any code that checks whether something is A_FLOAT or not,
> and branches accordingly, it makes absolutely no speed difference for
> the case of A_FLOAT.
>
> And for the other case... the difference is that if you rely on A_SYMBOL
> from being a type completely separate from A_FLOAT, for any reason, then
> you're toasted. It's actually the same issue as the auto-convert
> discussion from a while ago in which the symbol \123 would be regarded
> as float 123 if you look at it this way, or as symbol \123 if you look
> at it this way.
>

That's why I think it's better to insert filter objects in front of just 
the appropriate objects, to prevent unintended conversions and not waste 
time checking to see if something might be convertible for no reason. 
IMHO pdlua is really good for symbol parsing, as it doesn't use the 
symbol table, and the script can be edited without needing to compile 
it, and it's just easier to manipulate strings in lua.

Martin