You could provide a way to explicitly pass locations

[gasche]

Using the calltrace information is a fragile way to get location information -- in particular it requires programs to be compiled with -g. You should consider also providing an API that allows user to pass a location explicitly (and I would argue that the short name on the "path of least effort" should be this function, with eg. journal_send_implicit for the callstack-inspecting version).

Locations can be passed manually after having been inserted automatically by a syntactic processing pass (eg. one could think of a [%located journal_send] foo bar extension).

As of 4.02, OCaml provides the (admittedly under-documented, and of debatable elegance) __LOC__, __FILE__ and __LINE__ macros. so you could just encourage users to consistently write journal_send __LOC__ ... without the syntactic sugar.

Note that beside removing the requirement to consistently use -g, this gives user more control on the reported location. In particular, if (as a library user) you define auxiliary functions to perform the logging, you may want to report the location of the caller function instead, and letting user explicitly manipulate location as first-class values gives them the flexibility to decide this.

[juergenhoetzel]

@gasche Thanks for pointing that out. I wasn't aware of the new macros. I felt something was wrong after implementing get_callstack hack 😞