Determine If Parameter Has Expression?

[harrybiddle]

Hi guys, I'm hoping you can help me out. I have a C++ SOP that lives inside an OTL. The C++ SOP has a parameter "myparm" that references one of the same name on the OTL; i.e.

• OTL has a parameter "myparm" and a child node that is the C++ SOP
• Child C++ SOP parameter "myparm" has value ch("../myparm")

What I'm trying to do is, inside the C++ code of the SOP, work out if the OTL "myparm" has an expression or not. Something like

1. follow "myparm" to the OTL parameter
2. Work out if that parameter has an expression (I found that OP_Parameters::getStringMeaning could be used for this purpose, but please let me know if there's a better way)

Any ideas gratefully appreciated!

 

Thanks,

 

Harry

[Guest mantragora]

OP_Parameters::getStringMeaning returns enum CH_StringMeaning with four positions to compare

CH_STRING_LITERAL 	
CH_OLD_EXPRESSION 	
CH_PYTHON_EXPRESSION 	
CH_EXPRESSION_IN_DEFAULT_LANGUAGE

so I don't think that you can figure out anything better

To be fair I'm not following what's the problem here since you already answered how it should be solved?! Have you tried it? Or do you want us to try it and come back to tell you that it works

Edited January 10, 2014 by mantragora

[harrybiddle]

Ok cool; that's all fine then!

So the only thing I need is how to "deference" expressions. If my parameter has an expression "ch("../myparm")" then how do I follow that path to get access to the parameter it's referencing? I want to do something like this:

parameter_reference = evalParameterAsString("myparm", now);                       // gives me "ch(../myparm)"
parent_parameter = dereferenceExpression(parameter_reference);
parent_parameter_has_expression = getStringMeaning(parent_parameter, now);

Edited January 10, 2014 by harrybiddle

[edward]

This will follow all channel references until it does not find a simple ch("/to/parm") expression. The variables node/parm/vec_i will be updated to the new parameter.

OP_Node* node = this;
PRM_Parm* parm  = &node->getParm("myparm");
PRM_Parm *old_parm = parm;
int vec_i = 0;
OP_Parameters::followChannelReferences(now, node, parm, vec_i);
if (parm != old_parm && vec_i != 0) // then we changed to a new parameter
{
    CH_Channel* chp = parm->getChannel(vec_i);
}

[harrybiddle]

This works ideally: thanks to you both.