I wonder if something like this can be made available for redbean as well (or maybe it already is and just need to be exposed to the Lua layer)? @jart?

@pkulchenko Absolutely. Lua doesn't require parens in function calls, and it lets you pass code to a function, so we could probably define the syntax as follows:

ftrace {
  some_code()
}

@pkulchenko Absolutely. Lua doesn't require parens in function calls, and it lets you pass code to a function, so we could probably define the syntax as follows:

ftrace {
  some_code()
}

@jart, we may need to tweak this a bit, as it will call some_code and then pass the results. So, maybe either: ftrace(some_code) (to pass an existing function) or ftrace(function() some_code() some_other_code() end) to pass a closure).

If we're setting/removing a hook, then ftrace_start() and ftrace_stop() may be appropriate as well.

I've been also wondering if it's possible to keep the trace output internal and implement sort of a sliding window for it: ftrace_start(50) turns it on, but doesn't generate any output and always keeps the last (up to) 50 calls; I can then call ftrace_flush() and the collected info is then flushed to stderr. This way I don't need to go through the entire log and can add _flush to the places where I need it (and it may be better than start/stop, since I may come to the same place from multiple points and want to see which branch is being triggered).