fix: remove evals from model parsing

[ven-k]

Closes #2377

• Along with MTKModels with component arrays, the ones with icons of Expr type had this issue.
• This PR ensures that modules with either of those can be precompiled.

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the ScioML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

[ChrisRackauckas]

Suggested change

	parse_icon!(Core.eval(mod, body), dict, icon, mod)
	parse_icon!(getfield(mod, :body), dict, icon, mod)

? Example of what you're evaling

[ven-k]

This

@mtkmodel ModelWithExprIcon begin
    @icon read(abspath(@__DIR__, "..", "icons", "ground.svg"), String)
    # or @icon ground_logo 
end

from tests - here is an example.

In general,
anything with

@mtkmodel A begin
    @icon begin
        ...
    end
end

The body is an expression that should be evaluated within the defining module mod; in our test example that is ModelParsingPrecompile.
getfield can't be used as body is an expression in the module and not a function or a variable.

[ChrisRackauckas]

Simplify that to just the string as a path to an SVG?

[ven-k]

I checked; if @icon abspath() is used instead of plane string, that would need this too.

Core.eval doesn't suffer with the same issue as Base.eval; is there any performance issue with it?

In that case we can force to assign abspath() value to a var; and rewrite this only for Symbol (and drop Expr)

parse_icon!(body::Symbol, dict, icon, mod) = parse_icon!(getfield(mod, body), dict, icon, mod)

[ven-k]

I've dropped the Core.eval and Expr dispatch from the @icon parser.

Resolved it here.

[ven-k]

Doc doesn't need to be updated as it uses strings to showcase all 3 ways (URI, inlined SVG, paths).

[ChrisRackauckas]

Rebase?

[ven-k]

Already done 👍