compose() shadows Compose.compose

[jiahao]

The compose function shadows Compose.jl's primary function, compose, which makes it very difficult to work with together, e.g. when drawing custom graph layouts building upon GraphLayout.jl.

using Compose
using LightGraphs
compose(context(), rectangle(0, 0, 1, 1))
#Error:`compose` has no method matching compose(::Context, ::Form{RectanglePrimitive{P<:Point{XM<:Measure{S,T},YM<:Measure{S,T}},M1<:Measure{S,T},M2<:Measure{S,T}}})

using Compose
compose(context(), rectangle(0, 0, 1, 1))
using LightGraphs
#Warning: using LightGraphs.compose in module Main conflicts with an existing identifier.

Can we do something about this? Maybe rename compose to something else?

[sbromberger]

I don't have an issue with renaming it (to, say, merge) - the name comes from the NetworkX function of the same name.

A bigger question, though: what's "standard practice" when two function names collide in Julia?

[sbromberger]

Closing per #36. @jiahao - I have some other things that I'd like to get into the next tagged version so please go ahead and use Pkg.checkout() for now, if that's ok. Thanks!

[jpfairbanks]

It might be good to have what is no called merge be union and have what is now called union be blkdiag to match the sparse matrix operation.

Then we have the properties:

union(g, h) = graph(union(V(g), V(h)), union (E(g), E(h))).

And

adjmat(blkdiag(g, h)) = blkdiag(adjmat(g), adjmat(h)) .

The symmetry is pleasing and makes it easy to understand.

Not a crisis but better to get the names right now when the user base is small than in the future when it will disrupt many users.

[sbromberger]

I took the names directly from the NetworkX functions that perform the same activity. In general I'd like to keep in parallel with that package since it's what I'm most familiar with :) Renaming compose to merge was a one-off to avoid issues with another package.

[jiahao]

There's really no way to deal with name collisions of this form in Julia. The best one can do is to test if the generic function is already defined, and if so, import it before defining the new method, and hope that there are no ambiguity warnings. If you do all this, then if you load Compose then LightGraphs, then should work. It will still fail if you load LightGraphs then Compose because Compose needs to do the same thing.

@sbromberger I can see the utility of paralleling the NetworkX names; however @jpfairbanks has a point about mapping the functionality onto new methods of existing functions in base Julia. It's worth thinking about.

[jpfairbanks]

It speaks to a broader point in Julia because we went to be easy to migrate Matlab R and Python users to Julia but we also need to make sure we are internally consistent. On Apr 4, 2015 10:54 AM, "Jiahao Chen" notifications@github.com wrote:

There's really no way to deal with name collisions of this form in Julia. The best one can do is to test if the generic function is already defined, and if so, import it before defining the new method, and hope that there are no ambiguity warnings. If you do all this, then if you load Compose then LightGraphs, then should work. It will still fail if you load LightGraphs then Compose because Compose needs to do the same thing.

@sbromberger https://github.com/sbromberger I can see the utility of paralleling the NetworkX names; however @jpfairbanks https://github.com/jpfairbanks has a point about mapping the functionality onto new methods of existing functions in base Julia. It's worth thinking about.

— Reply to this email directly or view it on GitHub https://github.com/JuliaGraphs/LightGraphs.jl/issues/35#issuecomment-89590534 .

[sbromberger]

Ok, I'm open to renaming. Sorry for pushing back - I guess I can be a bit of a grump when it comes to changing something I know already (been using NX for years). Can someone make a PR?

Also, what's adjmat?

[jpfairbanks]

My shorthand for adjacency matrix. On Apr 4, 2015 11:13 AM, "Seth Bromberger" notifications@github.com wrote:

Ok, I'm open to renaming. Sorry for pushing back - I guess I can be a bit of a grump when it comes to changing something I know already (been using NX for years). Can someone make a PR?

Also, what's adjmat?

— Reply to this email directly or view it on GitHub https://github.com/JuliaGraphs/LightGraphs.jl/issues/35#issuecomment-89593347 .

[sbromberger]

of course - sorry - it's 0819 here and I haven't had caffeine.

I get it now, and I like the elegance. Please disregard my earlier objections.

[sbromberger]

Reopening to track second rename effort.

[sbromberger]

Closing per #43.