Placeholder syntax

Hello,

What is the different between the syntax?

Select * from "_SYS_BIC"."TAB_NAME"

('PLACEHOLDER' = ('$$AAA$$,'xxxx') )

And

Select * from "_SYS_BIC"."TAB_NAME"

(PLACEHOLDER."$$AAA$$ => 'xxxx ')

The first one returns wrong result and with the second one we cant use in a script CV.

Is there a meaning to the different syntax?

Thanks,

Amir