Blended tokens indexing mode. Optional, default is trim_none. Introduced in version 2.0.1-beta.

By default, tokens that mix blended and non-blended characters get indexed in there entirety. For instance, when both at-sign and an exclamation are in blend_chars, "@dude!" will get result in two tokens indexed: "@dude!" (with all the blended characters) and "dude" (without any). Therefore "@dude" query will not match it.

blend_mode directive adds flexibility to this indexing behavior. It takes a comma-separated list of options.

blend_mode = option [, option [, ...]]
option = trim_none | trim_head | trim_tail | trim_both | skip_pure

Options specify token indexing variants. If multiple options are specified, multiple variants of the same token will be indexed. Regular keywords (resulting from that token by replacing blended with whitespace) are always be indexed.

Returning to the "@dude!" example above, setting blend_mode = trim_head, trim_tail will result in two tokens being indexed, "@dude" and "dude!". In this particular example, trim_both would have no effect, because trimming both blended characters results in "dude" which is already indexed as a regular keyword. Indexing "@U.S.A." with trim_both (and assuming that dot is blended two) would result in "U.S.A" being indexed. Last but not least, skip_pure enables you to fully ignore sequences of blended characters only. For example, "one @@@ two" would be indexed exactly as "one two", and match that as a phrase. That is not the case by default because a fully blended token gets indexed and offsets the second keyword position.

Default behavior is to index the entire token, equivalent to blend_mode = trim_none.

Example:

blend_mode = trim_tail, skip_pure