Truncation of text values

[nichtich]

Name and value of the truncate parameter may be changed to also support other query extensions (regular expressions, ranking…).

[nichtich]

The most common cases for string search seem to be

• exact search (default)
• right-truncation
• substring
• regex

This cases could be enabled per field

• notation=ABC
• notation^=A
• notation*=B
• notation~=^AB?C*$

At least regex search (which regex language?) should better be an extension.