convert output to string only when needed?

[ltalirz]

e.g. calcAV currently returns its results in an output string.

If one wants to use these values further down the toolchain, they will need to be parsed, i.e. one is doing: compute values => produce string => parse string to get values

What about returning a std::map<std::string, std::double> instead and having a function that prints them out as a string when needed?

[ltalirz]

Discussion with Maciek: already done for major parts of zeo++ but not all functions may be converted