[masklinn]

> My favourite solution by far, though, is the one recently implemented by Elixir: log() is a regular function, but takes a closure instead of a string.

A pretty common halfway solution (used by Python's logging for instance) is that the logging library takes a format string and its parameters, and does the formatting itself.

Doesn't save intermediate lookups or complex computations if they exist, but for the common case of a complex stringification it can save your bacon.

The alternative is an explicit conditional around the logging call, which is definitely worse than the ability to log a closure.