I’m trying to figure out how to break down a complicated search query in Perl. It’s like the advanced search in email apps. Here’s what I want to do:
Take a search string like tag:stuff from:{person1 person2} {-tag:x from:person3} and turn it into a tree structure. Something like this:
my $tree = {
all => [
'tag:stuff',
{any => ['from:person1', 'from:person2']},
{any => [{not => 'tag:x'}, 'from:person3']}
]
};
The search rules are:
- Words with spaces mean AND
- Stuff in {} means OR
- Words with - in front mean NOT
These can be mixed up too. Like {from:bob -{tag:work from:alice}} etc.
I’m wondering if I should use a fancy grammar thing or if simple regex would work. Any ideas on good Perl modules for this kind of parsing?
I want to use this to make database queries later. Thanks for any help!
For complex search query parsing in Perl, I’d recommend looking into the Text::Balanced module. It’s particularly adept at handling nested structures and balanced delimiters, which seems crucial for your use case. You could use it to extract the {} groups first, then process the contents further.
Another approach might be to use a combination of Text::ParseWords for initial tokenization and a custom recursive function to build your tree structure. This method allows for more fine-grained control over the parsing process.
Regarding database queries, consider using SQL::Abstract to translate your parsed tree into SQL. It provides a flexible way to construct queries programmatically, which should mesh well with your tree structure.
Remember to thoroughly test your parser with edge cases to ensure robustness.
sounds like a tricky one! have u considered using Parse::RecDescent? it’s great for building custom parsers in perl. might be overkill for simple queries, but could handle the nested stuff well. regex could work too, but gets messy fast with all the nesting. good luck!
As someone who’s tackled similar parsing challenges, I’d suggest looking into Regexp::Grammar. It’s a powerful Perl module that lets you define complex grammars using regular expressions, which seems perfect for your nested search query structure.
I’ve used it for parsing log files with intricate patterns, and it handles nested structures beautifully. The learning curve is a bit steep, but once you get the hang of it, you can create incredibly flexible parsers.
For your specific case, you could define rules for each element (tags, from clauses, nested groups) and build your tree structure as you parse. It’s more maintainable than a giant regex and more performant than some heavier parsing solutions.
One tip: start with a simplified grammar and gradually add complexity. It’ll make debugging much easier. And don’t forget to add plenty of error handling - users can input some wild stuff in search boxes!