[Containers] add utilities to support extensions writing macros

[odow]

Part of #3513

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (44b56b1) 98.14% compared to head (b3ad761) 98.15%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3620      +/-   ##
==========================================
+ Coverage   98.14%   98.15%   +0.01%     
==========================================
  Files          43       43              
  Lines        5651     5634      -17     
==========================================
- Hits         5546     5530      -16     
+ Misses        105      104       -1     

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[pulsipher]

I tried this out in InfiniteOpt: infiniteopt/InfiniteOpt.jl#334

[pulsipher]

One workflow that I ended up copy and pasting a lot is:

base_name = get(kwargs, :base_name, string(something(name, "")))
if base_name isa Expr
    base_name = esc(base_name)
end
name_expr = _base_name_with_indices(base_name, index_vars)

where I also directly copied:

function _base_name_with_indices(base_name, index_vars::Vector)
    if isempty(index_vars) || base_name == ""
        return base_name
    end
    expr = Expr(:call, :string, base_name, "[")
    for index in index_vars
        # Converting the arguments to strings before concatenating is faster:
        # https://github.com/JuliaLang/julia/issues/29550.
        push!(expr.args, :(string($(esc(index)))))
        push!(expr.args, ",")
    end
    expr.args[end] = "]"
    return expr
end

It would be nice to have a public function of the form:

function parse_name_expr(name, kwargs, index_vars)
    base_name = pop!(kwargs, :base_name, string(something(name, "")))
    if base_name isa Expr
        base_name = esc(base_name)
    end
    return _base_name_with_indices(base_name, index_vars)
end

[odow]

Added Containerss.name_with_index_expr

[pulsipher]

Added Containerss.name_with_index_expr

Thanks, I just updated the InfiniteOpt PR accordingly.

[odow]

Nice. I think we're converging on some good improvements to the macro code.

[odow]

I'm fairly happy with this, so I'd propose we merge unless there are suggestions for further improvements.

It has made infiniteopt/InfiniteOpt.jl#334 a lot nicer

[odow]

I'll merge this for now. Then I plan to open a PR ticking off the macro rewrite from the roadmap, so that can be the gate for people to review the full sequence of changes that I have been making. We're not in a rush to release JuMP v1.18.