Feature #3809

Updated by mame (Yusuke Endoh) about 6 years ago



The current set_trace_func() method in Ruby 1.8 and 1.9 cannot be safely
called multiple times because each call overwrites the current trace_func.

Please consider adding a mechanism, such as the multitrace library[1], to
allow users to attach multiple tracing functions simultaneously to Ruby.

An alternative to the multitrace library[1] is to add some new methods:

* attach_trace_func(proc) #=> proc
* detach_trace_func(proc) #=> proc

When you call attach_trace_func(), it will register your tracing
function and return it. You can pass the same tracing function
later to detach_trace_func() to unregister it.

Here is a convoluted example:

detach_trace_func(attach_trace_func(proc {}))

Here is a more realistic example:

foo = proc {}
bar = proc {}
attach_trace_func foo
# ...
attach_trace_func bar
# ...
detach_trace_func foo
detach_trace_func bar

Thanks for your consideration.