AviSynth syntax: optional and named arguments

[stax76]

I'm working on a program where I want to
change filter arguments with controls.
I don't understand when a argument can
be named. The doku says optional arguments
can be named but how do I know a argument
is optional. Would it be possible to
write the doku like this

BicubicResize(clip, int target_width, int target_height, optional float "b" = 1 / 3, optional float "c" = 1 / 3)

this is the Visual Basic way, it tells which parameter is
optional and it's default value

'Dolemite

[Wilbert]

On the docs you will get when downloading avisynth:

BicubicResize(clip, int target_width, int target_height, float "b", float "c")

the default values are given in the text.

On avisynth.org it should be (but it isn't always):

BicubicResize(clip, int target_width, int target_height [, float b = 1/3] [, float c=1/3])

[stax76]

BicubicResize(clip, int target_width, int target_height [, float b = 1/3] [, float c=1/3])

Even better, I did't know it's used already in some descriptions. I wonder if there will be a XML type structure to get this information so I don't have to write my own filter description file, I know this was discussed already. Would not only be useful for GUI applications, also the doku could be createt dynamically.

'Dolemite