Details
problem where "square brackets" are not carried to the UDF expression generated when inserting the UDF.
If "square brackets " are used in the new parameter prompt when defining a UDF, the expression name will not be inherited after inserting the target part, and will be [P + <feature number>].
The same behavior can be seen by using "round brackets".
Solution
Open Expression editor (Ctrl+E) and try to create a new expression with a name in brackets, say [xyz], the expression editor will pop up alert about invalid naming. NX expression names do not accept special characters like [,],*, etc.
In simple words, the standard naming convention for C/C++ variables apply here to NX expression naming.
Notes and References
9578985
Hardware/Software Configuration
Platform: INTL64
OS: windows
OS Version: 1064
Product: NX
Application: DESIGN
Version: V1847
Function: FEATURE_MODEL
Ref: 002-8170957