`break /foo/` for matched method

No files, tests, or implementation entry points are named. Start by tracing how the debugger parses and installs the existing break command, then determine how pending breakpoints and future method definitions are handled. Done means an agreed regexp notation and behavior for matching method names, including tests for existing and future definitions.

gdb has rbreak regexp (https://sourceware.org/gdb/onlinedocs/gdb/Set-Breaks.html) and maybe debug.gem can provide similar feature.

related to: https://github.com/ruby/debug/issues/655

Questions:

• Notation:
  • break /foo/ all methods which names contains foo.
    • C1#foo, C2#foobar, C3#bazfoo, ...
  • break C#/foo/: C's methods which contains foo.
    • C#foo, C#foobar, ...
    • Seem's ugly...
  • break /C/#foo: Method foo of classes which names contain C.
    • C1#foo C2#foo, ...
    • Seems ugly too.
  • Only allow break /C#foo/ or break /C\.foo/ and so on?
  • Only allow to match method name?
    • It seems simple. We can extend it later.
• Behavior:
  • Set breakpoints for existing matched methods (no problem)
  • Set breakpoints for future defined matched methods?
    • break /initialize/ means all initialize methods (and defined in future) can be trapped.
    • maybe it is convenient to support it.
  • Can we support break /obj.foo/ style?
    • maybe no if we allow future defined methods.

So current idea is:

• break /regexp/ set method breakpoints where the method name matched with Class/Module/method name.
  • break /foo/ should be matched with:
    • C#foo
    • D.foo
    • E.bazfooboo
    • We can not match on class/module names (at least now).
• It leaves as a pending breakpoint and set breakpoint in future definitions. User needs to del it if you don't need more.