Function interface to `^Q` shortcut behavior and generalization to get last stacktrace

The ^Q shortcut lets a user jump to a source code line corresponding to a method or stackframe. It is just awesome. (It makes Julia a bit more like [the good parts of] SmallTalk)

What about a non-shortcut way to access the behavior? This would be useful if that shortcut doesn’t work for some reason (e.g. by default in VS Code), and could also possibly help with discoverability.

The current design remembers what was last displayed, and that information can be accessed in Base.active_repl.last_shown_line_infos. That structure is uniform whether what was displayed was a Base.MethodList or a a stacktrace via showerror.

What about a design that stores directly a Base.MethodList or a Vector{Base.StackTraces.StackFrame}?* Combined with a definition like

edit(sf::StackTraces.StackFrame) = edit(sf.file, sf.line)


getindex defined on Base.MethodList

It should then work out to do something like edit(Base.active_repl.last_shown[index]).

As an additional benefit, this could be a way to get the last stacktrace, which I often want to e.g. copy it to my clipboard.

*It’s not as simple as remembering in show_backtrace, but instead remembering in show_reduced_backtrace and show_full_backtrace. If the former is used, then Base.active_repl.last_shown should be bound to displayed_stackframes. This also means that there are two possible notions of the most recent stackframe…

(@tkf @simeonschaub)