Make Clusters hierarchical

DESCRIPTION

Is your change request related to a problem? Please describe. It's currently not possible to create hierarchical data structures, which makes mode advanced code nearly impossible.

Describe the solution you'd like Clusters should be able to contain anything, which means that they will need to contain themselves. Think about a syntax to identify an embedded object, e.g.

{x,y,{a,b,c},z} ~= {x,y,_~&_CSTREF,z}
cst{3} = addressof(CST{}); INTEGER
abc{} = copyof(cst{3});
abc{} = cst{3}{} REFERENCE?
abc{} = {x,y,{a,b,c},z}
abc{} = {x,y,TAB(),z}
abc{3} = {a,b,c}

Describe alternatives you've considered No alternative available

Additional context Migrated from here: https://sourceforge.net/p/numere/tickets/608/

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DEVS' SECTION

ANALYSIS

Enabling something like this requires that we adapt the mu::value_type typedef once more to enable arbitrary internal data types.

IMPLEMENTATION STEPS

(see also our Wiki for implementation guidelines)

Implement the necessary changes in a new branch created here on GitHub
Test your implementation

DOCUMENTATION STEPS

(see also our Wiki for further information)

Update the changes log
Add comments to your implementation
Add Doxygen documentation comments
Create or update the documentation articles (*.NHLP and *.NDB files, if needed)
Update the language strings (*.NLNG files, if needed)

PULL REQUEST

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numere-org / NumeRe