[logopen()](logopen.md) does this internally, but you might want to manually
craft the `"regex":` for a .fmt descriptor.  In such cases,
you can use `regex()` or `update()` to combine the log.fmt with definitions
from the global fmt database.


### regex()

Takes a .fmt json/dict, and generates the regex with named capture groups
from it.

::: logfmt1.regex


----


### rx2re()

::: logfmt1.rx2re


----

### update()

Updates the `regex:` property in a .fmt dict. Also injects any used
`fields:` or `alias:` lists. (For now this is basically just a wrapper
of the `regex()` builder.)

::: logfmt1.update
