Add constructvariablecontainer! function

[blegat]

Depends on #1038
This could help creating different containers like AxisArrays #980

[chriscoey]

we are doing some housekeeping, so bumping this. anything we need to discuss?

[codecov]

Codecov Report

Merging #1039 into master will increase coverage by 0.03%.
The diff coverage is 97.5%.

@@            Coverage Diff             @@
##           master    #1039      +/-   ##
==========================================
+ Coverage   90.63%   90.66%   +0.03%     
==========================================
  Files          18       18              
  Lines        4623     4617       -6     
==========================================
- Hits         4190     4186       -4     
+ Misses        433      431       -2

Impacted Files	Coverage Δ
src/JuMP.jl	91.74% <ø> (-0.03%)	⬇️
src/macros.jl	91.79% <97.5%> (-0.05%)	⬇️
src/solvers.jl	95.84% <0%> (-0.01%)	⬇️
src/operators.jl	92.23% <0%> (+0.59%)	⬆️

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[codecov]

Codecov Report

Merging #1039 into master will increase coverage by 0.03%.
The diff coverage is 97.5%.

@@            Coverage Diff             @@
##           master    #1039      +/-   ##
==========================================
+ Coverage   90.63%   90.66%   +0.03%     
==========================================
  Files          18       18              
  Lines        4623     4617       -6     
==========================================
- Hits         4190     4186       -4     
+ Misses        433      431       -2

Impacted Files	Coverage Δ
src/JuMP.jl	91.74% <ø> (-0.03%)	⬇️
src/macros.jl	91.79% <97.5%> (-0.05%)	⬇️
src/solvers.jl	95.84% <0%> (-0.01%)	⬇️
src/operators.jl	92.23% <0%> (+0.59%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 02b8865...af3753b. Read the comment docs.

[blegat]

@chriscoey Yes, I have just rebased it now that #1038 has been merged and I'd like to know what you think of it :)

[mlubin]

There's no documentation, what does this change?

[blegat]

Yes documentation should be added. It basically calls constructvariablecontainer with the extra arguments. This allows to do the special treatment of SDP and Symmetric not so special. The issue is that this not done in evaluation of the code so we still have :SDP and :Symmetric as symbols. Therefore we should evaluate the part of extra that is used for building the container but not evalueate the part that is used to build each part yet... This still needs some thought but comments are welcome :)

[mlubin]

Looks like this is stale, can we close?

[blegat]

Yes, we can try to make the change later