lazily view hierarchies on disk

[bjarthur]

JLD2.jl, MAT.jl, HDF5.jl, and maybe others could benefit from being composed with REPLTreeViews.jl. how hard would it be to add support for say fid=h5open(...); @iview fid. i could help with this if you gave me a tip on where to start.

[jmert]

It looks like for HDF5.jl, getting the names printed out in a tree is relatively easy (assuming the functions in JuliaIO/HDF5.jl#725), but with only a couple minutes' reading of code here I don't see how to print the data contents (since HDF5 Datasets are also nodes for any attached attributes):

using HDF5
import TreeViews

let H5Trees = Union{HDF5.File,HDF5.Dataset,HDF5.Group,HDF5.Attributes}
    TreeViews.hastreeview(::H5Trees) = true
    TreeViews.numberofnodes(o::H5Trees) = length(HDF5._tree_children(o, true)[1])
    TreeViews.nodelabel(io::IO, o::H5Trees, i::Integer, ::MIME"text/plain") = print(io, HDF5._tree_children(o, true)[1][i])
    TreeViews.treenode(o::H5Trees, i::Integer) = HDF5._tree_children(o, true)[2][i]
end

using REPLTreeViews

julia> hfile = h5open("/tmp/test_file.h5")

julia> @ishow hfile
HDF5.File
 ▶  creator
 ▶  description
 ▶  R
 ▶  fields
 ▼  pixels_left
    ▼  HDF5.Group
       ▶  description
       ▼  dec
         [ ] HDF5.Dataset
            
       ▶  order
       ▶  ra
       ▶  type
 ▶  pixels_right