正向超前+重叠匹配正则表达式

Question

I'm looking for a regex to match all % that are not followed by a valid 2-characters hex code (2 characters in a-fA-F0-9). I came up with (%)(?=([0-9a-fA-F][^0-9a-fA-F]|[^0-9a-fA-F])) which works well but is not supported in golang, because of the positive lookahead (?=).

How can I translate it (or maybe make it simpler?), so that it works with go?

For example, given the string %d%2524e%25f%255E00%%%252611%25, it should match the first % and the first two ones of the %%% substring.

ie: https://regex101.com/r/y0YQ1I/2

Answer 1

I only tried this on regex101 (marked golang regex), but it seems that it works as expected:

%[0-9a-fA-F][0-9a-fA-F]|(%)

or simpler:

%[0-9a-fA-F]{2}|(%)