I have a file with many records. Fields are delimited by tab. One of the fields is a list of comma separated keywords. What I want is to extract only those records that have keywords according to an expression given on runtime.

Is there a package available that can create a single regular expression starting from a string like the following ones?

moe&(shemp|curly|joe)&larry
(tom&jerry)|(sylvester&tweety)
[download]

If I have to do that by myself, I can manage the ORs with something like this in the regex:

\b(one|two|three)\b
[download]

but I'm not sure how to handle the ANDs. I've done some tests with advanced expressions like (?=word) without understanding what is really going on.

I also thought on sorting each keywords list to allow simple regex being written as \bone\b.*\btwo\b, but is useless if I want to search for:

olive&(popeye|bluto)
[download]

Hints, please?

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