Re: [Csnd-dev] [EXTERNAL] [Csnd-dev] default arguments for UDOs in new syntax

This fix is just to bring newstyle UDOs to the same level of functionality as the original form. I did not touch the parser per se, just adjusted the semantic analysis to accept and translate optional types into i or k, as needed.

To get a syntax like

opcode myop(var:i=5)

we need to insert a rule in the parser to look for that pattern, then add code in the semantic analysis to understand it, and then adapt the UDO inargs reading to understand it.

I have not looked into it to see how much work it is yet, so I can't really say. One thing I noticed is that the new parser is much easier to extend than the previous iteration.

Prof. Victor Lazzarini
Maynooth University
Ireland

On 29 Jul 2025, at 17:51, Eduardo Moguillansky <[email protected]> wrote:


The parser is an area of csound which I know nothing about. How far is it from being able to implement named arguments at the call site and, with that, arbitrary default arguments?

On Tue, Jul 29, 2025 at 9:48 PM Victor Lazzarini <[email protected]<mailto:[email protected]>> wrote:
I’ve made a PR fixing this.
Optional types as per classic-style UDO are now allowed as types.

https://github.com/csound/csound/pull/2214

========================
Prof. Victor Lazzarini
Maynooth University
Ireland






> On 29 Jul 2025, at 19:35, Victor Lazzarini <[email protected]<mailto:[email protected]>> wrote:
>
> Defaults arguments are not implemented as far as I can see.
> This works - but I think it is a fluke.
>
> opcode myop(var1:i,var2:p):void
> print var1, var2
> endop
>
> Steven should be able to clarify. I’ll have a look at the code
>
> ========================
> Prof. Victor Lazzarini
> Maynooth University
> Ireland
>
>> On 29 Jul 2025, at 19:14, joachim heintz <[email protected]<mailto:[email protected]>> wrote:
>>
>> *Warning*
>>
>> This email originated from outside of Maynooth University's Mail System. Do not reply, click links or open attachments unless you recognise the sender and know the content is safe.
>>
>> in the old UDO syntax, we had opj etc for some default values of arguments.
>> is there something in the new UDO syntax?
>> i tried
>>      opcode test(arg1:i=1,arg2:i=13):void
>> but this did not work.
>