Re: Embedded Python Block Tutorial Param ID Error

Hi Sebastian,

Thanks for the reply. I could rerun the flowchart by deleting the epy python
files and the __pycache__ subdirectory, close and reopen GRC. It would allow me
to run it once more before the same Param ID error appeared. So i suppose it is
that commit that is responsible (but I dont know how to confirm it).

Whats interesting though is that I notice that the same patch was included in
maint3.9 but I did not encounter this problem at all with the code I compiled
from maint3.9. I only had this problem with the master branch as of my first
email today.

I would love to fix this bug but I just started using GRC so Im still unfamiliar
with the software. Would you like me to open an Issue on Github to make it
easier for the gr-dev team to solve the issue?

Cheers,
Sol

On 8/5/21 3:40 pm, Sebastian Koslowski wrote:
> Hi, 
>
> that looks like a bug introduced by
> https://github.com/gnuradio/gnuradio/pull/4522
> <https://github.com/gnuradio/gnuradio/pull/4522>
> We forgot to special-case / adapt epy blocks...
>
> Sebastian
>
> (von unterwegs gesendet)
>
> On Sat, May 8, 2021, 06:23 Solomon Tan <solomonbstoner@yahoo.com.au
> <mailto:solomonbstoner@yahoo.com.au>> wrote:
>
> Dear all,                       
>                                                 
> I was following the GNURadio Embedded Python Block Tutorial. After adding a     
> Python block, I got the following error.                                        
> ```                                                                             
> Param - Id(id):                                                                 
>         ID "epy_block_0" is blacklisted.                                        
> ```                                                                             
> The parameter ID of the Python block is marked in red. Why and how? The 
> weirdest thing is that the Python block worked initially at first. I could
> run the
> flowgraph, but after stopping it, I couldnt rerun it again. I was given that
> Param
> ID error. My code was almost equivalent to the template, so it cant be my fault
> , right?
> ```
> """
> Embedded Python Blocks:
> """
> import numpy as np
> from gnuradio import gr
>
> class blk(gr.sync_block):  
>     """Embedded Python Block example - a simple multiply const"""
>
>
>     def __init__(self, example_param=1.0):  # only default arguments here
>         """arguments to this function show up as parameters in GRC"""
>         gr.sync_block.__init__(
>             self,
>             name='EPB Multiply by Const',   # will show up in GRC
>             in_sig=[np.float32],
>             out_sig=[np.float32]
>         )
>         # if an attribute with the same name as a parameter is found,
>         # a callback is registered (properties work, too).
>         self.example_param = example_param
>
>
>     def work(self, input_items, output_items):
>         """example: multiply with constant"""
>         output_items[0][:] = input_items[0] *2 * self.example_param
>         return len(output_items[0])
> ```
>
> I could not find any other mail in the archive about this parameter ID error.
>
> Thank you.
> Cheers,
> Sol
>