CodeTracking

CodeTracking is a minimal package designed to work with Revise.jl (for versions after v1.1.0). Its main purpose is to support packages that need to interact with code that might move around as it gets edited.

CodeTracking is a very lightweight dependency.

Example:

julia> using CodeTracking

julia> m = @which sum([1,2,3])
sum(a::AbstractArray) in Base at reducedim.jl:648

julia> file, line = whereis(m)
("/home/tim/src/julia-1/usr/share/julia/base/reducedim.jl", 642)

In this (ficticious) example, sum moved because I deleted a few lines higher in the file; these didn't affect the functionality of sum (so we didn't need to redefine and recompile it), but it does change the starting line number of the file at which this method appears.

Other methods of whereis allow you to obtain the current position corresponding to a single statement inside a method; see ?whereis for details.

CodeTracking can also be used to find out what files define a particular package:

julia> using CodeTracking, ColorTypes

julia> pkgfiles(ColorTypes)
PkgFiles(ColorTypes [3da002f7-5984-5a60-b8a6-cbb66c0b333f]):
  basedir: /home/tim/.julia/packages/ColorTypes/BsAWO
  files: ["src/ColorTypes.jl", "src/types.jl", "src/traits.jl", "src/conversions.jl", "src/show.jl", "src/operations.jl"]

or to extract the expression that defines a method:

julia> m = @which red(RGB(1,1,1))
red(c::AbstractRGB) in ColorTypes at /home/tim/.julia/packages/ColorTypes/BsAWO/src/traits.jl:14

julia> definition(m)
:(red(c::AbstractRGB) = begin
          #= /home/tim/.julia/packages/ColorTypes/BsAWO/src/traits.jl:14 =#
          c.r
      end)

julia> definition(m, String)
"red(c::AbstractRGB   ) = c.r\n"

or to find the method-signatures at a particular location:

julia> signatures_at(ColorTypes, "src/traits.jl", 14)
1-element Array{Any,1}:
 Tuple{typeof(red),AbstractRGB}

julia> signatures_at("/home/tim/.julia/packages/ColorTypes/BsAWO/src/traits.jl", 14)
1-element Array{Any,1}:
 Tuple{typeof(red),AbstractRGB}

A few details

CodeTracking won't do anything useful unless the user is also running Revise, because Revise will be responsible for updating CodeTracking's internal variables. (Using whereis as an example, CodeTracking will just return the file/line info in the method itself if Revise isn't running.)

However, Revise is a fairly large (and fairly complex) package, and currently it's not easy to discover how to extract particular kinds of information from its internal storage. CodeTracking is designed to be the new "query" part of Revise.jl. The aim is to have a very simple API that developers can learn in a few minutes and then incorporate into their own packages; its lightweight nature means that they potentially gain a lot of functionality without being forced to take a big hit in startup time.