Hello, Picking up an old thread... I am looking for a way to trigger a specific constructor when loading an object from a JLD file.
FileIO detects the files are JLD, and that is great, but it would be cool if it could trigger my constructor `MyModule.MyType(objectfromjld)` when - `MyModule` was specified in the addrequires while writing the file - `JLD.exists(io, "MyType")` (namely the object `objectfromjld`) (The case here is that MyType contains a field that is largish and that can be precomputed from another field in the type, which is the want I want to store in the file). I've tried to write a `detectmytype()` in the spirit of, say, `FileIO.detecthdf5()`, but I am kind-of stuck here: - the detect...() interface wants an IO object (I think) - I can find out if `MyType` exists from `jldopen(filename)`, but I can't find an interface for hdf5/jld for an IO object. Does anyone know how I could get this done? Thanks, ---david On Wednesday, September 30, 2015 at 11:35:20 AM UTC+2, Tim Holy wrote: > > Probably best as an issue over at FileIO. > > --Tim > > On Wednesday, September 30, 2015 01:24:25 AM David van Leeuwen wrote: > > Hello Tim and Simon, > > > > I'd be very interested in this, for MFCCs.jl and perhaps > > GaussianMixtures.jl. They currently use HDF5 and JLD, respectively, and > I > > don't think I've put in any magic. > > > > - is it wise to put in magic, even with container formats such as HDF5? > > > > - do you prefer questions about implementation on this list, the repo, > or > > some other way (or not at all)? > > > > Cheers, > > > > ---david > > > > On Tuesday, September 29, 2015 at 9:24:13 PM UTC+2, Tim Holy wrote: > > > Simon Danisch and I are pleased to introduce FileIO.jl > > > (https://github.com/JuliaIO/FileIO.jl), a package for centralizing > the > > > handling of formatted files. The package contains utilities for > querying > > > files/filenames by their extensions and/or magic bytes to deduce their > > > content. > > > It then allows package authors to "register" loaders/savers for > detected > > > file > > > formats. > > > > > > Some of the advantages of using FileIO are: > > > > > > - For users, this may reduce the searching required to answer "is > there a > > > julia package to load file X?" Now you can just try `load("X.ext")` > and > > > see > > > what happens---if the loader has been registered, it will try to find > the > > > right > > > package for you. > > > > > > - For developers, this allows you to decouple your package from > others. If > > > you > > > want to work with images, you will (once I tag a new release of > Images.jl) > > > no > > > longer need to make the Images package a dependency as long as you use > > > FileIO. > > > In your package code, you can say `load("myimage.png")` and everything > > > should > > > Just Work. > > > > > > - For users and developers, this reduces name conflicts among two > > > attractive > > > function names, `load` and `save`. If everyone imports those names > from > > > FileIO, there need be no conflicts. > > > > > > The package is relatively small and is fairly extensively documented. > > > > > > While there are not a large number of formats currently registered, > the > > > architecture already shows a lot of promise. For example, it can > recognize > > > our > > > .jld files as HDF5 files, something that escapes the well-tested (and > much > > > more > > > extensive) Unix `file` command. > > > > > > Best, > > > --Tim & Simon > >
