Re: The semantics of the disambiguation constructs

On 04/02/2026 10:59, Norm Tovey-Walsh wrote:
> Steven Pemberton <steven.pemberton@cwi.nl> writes:
>> The fact that [] just fails to match feels so counterintuitive to
>> me! I keep forgetting about it.
>>
>> Michael insisted on us including it, so I suppose he had a use-case.
> 
> Having a way to “not match anything” makes sens. I think it’s just
> unfortunate that it’s syntactically problematic. It’s just so easy
> to glance at it and think “that matches nothing, ε” not “that can
> match no characters”.
> 
> I find the “match any character” construction, ~[], even more
> offensive to my aesthetic sensibilities, but I’ve just sort of
> resigned myself to get used to it and get it wrong occasionally when
> I’m in a hurry.
"not nuthin'" is indeed slightly uncomfortable, but I think it just 
means it needs an explanatory sentence to itself in documentation to 
reassure learners that it's right.

Peter

Received on Wednesday, 4 February 2026 21:24:45 UTC