trouble making my "messages needing a reply" pattern

[Cameron Simpson]

On 07Feb2021 19:04, Kevin J. McCarthy <kevin at 8t8.us> wrote:
>On Mon, Feb 08, 2021 at 12:49:32PM +1100, Cameron Simpson wrote:
>>I've winnowed my failing pattern down to
>>   ~( !~>(~P) )
>>which is not accepted.
>
>I think this is from a small bug with trailing whitespace inside 
>parentheses.  Try
>  ~(!~>(~P))

Thanks, that works. Cheers, Cameron