Enhance search with exact matches

[doekenorg]

Currently a DatavView only supports a search string. To make searching more powerfull we should introduce a Search value object with a ::from_string() constructor.

Instead of relying solely on the search string, the DataSource can parse the string into multiple parts.

For example a string like some +value -other "Exactly this" would be parsed to:

• CAN contain: some and Exactly this
• MUST contain: value
• MUST NOT contain other

We might also add operators for STARTS WiTH and ENDS WITH.

The data sources are still required to implement the search logic, but the value object should allow this parsing to happen.

And of course add a hook to disable this behaviour. And the value object should be Stringable (__toString()).

[doekenorg]

This is partly built by parsing the search string into a Search object. It uses Search::frrom_string( string $query ) to create an instance. It will parse the string into 3 parts (currently):

• required: MUST be in the dataset
• optional: CAN be in the dataset
• ignored: MUST NOT be in the dataset

Implementation details for data source:
The search_by() method now receives a Search object. String matches will probably still work as the object implements __toString to get the original (trimmed) search query.

• If the dataset is missing a required value, the dataset DOES NOT match
• If the dataset has an ignored value, the dataset DOES NOT match
• If the search query only contains optional values, the dataset only matches if it has AT LEAST ONE match
• If a search has optional values AND either required or ignored; the optional value MAY BE ignored for the match.