Allow edit to select method based on index; print available methods in edit error message

[MilesCranmer]

From #39476. cc @timholy

This PR adds the following:

1. A new function signature edit(f::Function, method_idx::Integer) that takes an array index for methods(foo).ms as input.
2. When a user calls edit(f), and the function has >1 signatures, print out methods(foo).ms to the console, in addition to the normal ERROR: function has multiple methods.

I think this gives a much quicker experience when trying to edit functions that have many signatures, making Revise.jl even smoother.

Here's an example workflow. Say I want to edit a method of function foo:

julia> edit(foo)
ERROR: Function has multiple methods; please specify a type signature:
# 2 methods for generic function "foo":
[1] foo(lt1::LongTypeName1, lt2::LongTypeName2; lt3::LongTypeName3) in Main at REPL[5]:1
[2] foo() in Main at REPL[4]:1
...
julia> edit(foo, 1)

Editor then opens method foo(lt1::LongTypeName1, lt2::LongTypeName2; lt3::LongTypeName3), instead of needing to write out manually edit(methods(foo).ms[1]) or try to write out all the types. And edit(foo) printing the methods is nice, since then I don't need to print methods(foo).ms myself to check the signatures.

The new error message for ambiguous edit on the function less looks like this:

julia> edit(less)
ERROR: function has multiple methods; please specify a type signature:
# 5 methods for generic function "less":
[1] less(file::AbstractString) in InteractiveUtils at /Applications/Julia-1.5.app/Contents/Resources/julia/share/julia/stdlib/v1.5/InteractiveUtils/src/editless.jl:255
[2] less(file::AbstractString, line::Integer) in InteractiveUtils at /Applications/Julia-1.5.app/Contents/Resources/julia/share/julia/stdlib/v1.5/InteractiveUtils/src/editless.jl:242
[3] less(f) in InteractiveUtils at /Applications/Julia-1.5.app/Contents/Resources/julia/share/julia/stdlib/v1.5/InteractiveUtils/src/editless.jl:263
[4] less(file, line::Integer) in InteractiveUtils at /Applications/Julia-1.5.app/Contents/Resources/julia/share/julia/stdlib/v1.5/InteractiveUtils/src/editless.jl:265
[5] less(f, t) in InteractiveUtils at /Applications/Julia-1.5.app/Contents/Resources/julia/share/julia/stdlib/v1.5/InteractiveUtils/src/editless.jl:264
Stacktrace:
 [1] error(::String) at ./error.jl:33
 [2] top-level scope at REPL[20]:1

Then one can choose a method from this list, with, e.g., edit(less, 2), instead of having to: 1) print out all the methods with methods(less), and 2) write out the tuple types or write edit(methods(less).ms[2]).

[fredrikekre]

This should probably just use the ^Q functionality in the REPL. It already works for stacktraces and displayed method lists. E.g.

julia> methods(match)
# 4 methods for generic function "match":
[1] match(re::Regex, str::Union{SubString{String}, String}, idx::Integer) in Base at regex.jl:294
[2] match(re::Regex, str::Union{SubString{String}, String}, idx::Integer, add_opts::UInt32) in Base at regex.jl:294
[3] match(r::Regex, s::AbstractString) in Base at regex.jl:315
[4] match(r::Regex, s::AbstractString, i::Integer) in Base at regex.jl:316

julia> 2[^Q]

jumps to the second method in the list.

[MilesCranmer]

Nice!!! I had no idea this trick existed, thanks. I will close this PR.

I guess this is an example of Cunningham's Law but for pull requests? 🤣

[fredrikekre]

I meant that it could be nice to make it work from this error too.

[MilesCranmer]

I see what you mean; that would be a nice addition.

Maybe edit(f::Function) could catch this error from functionloc, and return methods(f) instead?

[MilesCranmer]

How about this?

edit(f) = length(methods(f)) > 1 ? methods(f) : edit(functionloc(f)...)

[MilesCranmer]

Moved to #39481