Multiple tag exclusion doesn't work

[jarun]

The following query gives wrong results:

$ buku -t computer science - digital logic - assembly programming -z
OR
$ buku -t computer science - 'digital logic' - 'assembly programming' -z

[DEBUG] Version 3.6
[',computer science,']
OR
,digital logic - assembly programming,
2
[DEBUG] query: "SELECT id, url, metadata, tags, desc FROM (SELECT *, CASE WHEN tags LIKE '%' || ? || '%' THEN 1 ELSE 0 END AS score FROM bookmarks WHERE score > 0 AND tags NOT REGEXP ?  ORDER BY score DESC)", args: [',computer science,', ',digital logic - assembly programming,']
1. NPTEL [179]
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2. 50+ Free Online Course Torrents (Video Lectures) – Free Courses [185]
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3. Simply Scheme contents [211]
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   > https://xlinux.nist.gov/dads/
   # algorithms,computer science,interview

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   + A shop class for computer science.
   # computer science

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   # computer science,digital logic

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   # algorithms,computer science,interview

14. GitHub - mewrev/dissection: The dissection of a simple "hello world" ELF binary. [305]
   > https://github.com/mewrev/dissection
   # assembly programming,binary analysis,computer science,interview

15. Algorithms | Computer science | Computing |Khan Academy [323]
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   # computer science

16. Two's Complement [329]
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   # computer science

17. Cossack Labs / Zero Knowledge Protocols without magic [339]
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   # computer science

19. Demystifying Floating Point Precision « The blog at the bottom of the sea [390]
   > https://blog.demofox.org/2017/11/21/floating-point-precision/
   + What precision do I have at a number? When will I hit precision issues?
   # computer science

20. Teach Yourself Computer Science [407]
   > https://teachyourselfcs.com/
   + A well-designed Computer Science course.
   # computer science

The tags after the first - are combined together as a single tag and result 14 shows up.

[jarun]

@mosegontar could you please take a look? It seems we need to tweak prep_tag_search to handle multiple tags separated by -. It should also work with the following patterns:

+ - + -
and
- + - +

[jarun]

I think for simplification we should support just:

+ tag4
tag1 + tag2 - tag3 - tag4
- tag4

[jarun]

OK, I see that exclusion list can be separated by , however the the check for both + and , comes before that and trumps it.

[jarun]

@rachmadaniHaryono we need test cases for the api prep_tag_search().