Feature/explain expression

[mgyoo86]

Summary

This PR is to "explain" the detailed procedures when executing onetime or dynamic expressions in dd, which is to address the issue raised from the code camp (see Backend/user interace section in ProjectTorreyPines/FUSE.jl#786).

The more details and examples are described in the following PR:
ProjectTorreyPines/FUSE.jl#794

Dependency / Related PRs

This change depends on related PR in the IMASdd package to fully function:
ProjectTorreyPines/IMASdd.jl#47

Note

• CI might fail until dependent PRs are merged.
• Once the dependent changes are integrated, this PR should work as expected.

[orso82]

@mgyoo86 I ❤️ this! It's amazing!! You always manage to convey back to the user a lot of information in a very clear way :)

I wonder if the expr_info.jl file should live under IMASdd.jl, since that's where the base functionality of the expressions is implemented.

[mgyoo86]

@orso82 I am glad that you like this feature, and thanks for saying highly :)

I've tried to move expr_info.jl to under the IMASdd.jl, but the @store_expr macro defined in expr_info.jl does not work as expected.
The issue seems to be the different scopes of @store_expr, such that it is defined in the IMASdd scope but used in the IMAS scope, leading to some tricky conflict.

Hence, at the moment, I think we can allow expr_info.jl to live in the IMAS package, like onetime.jl and dynamic.jl.
FYI, if I move all three files (expr_info.jl, onetime.jl, dynamic.jl) to under the IMASdd, the new macros work as expected, except for some expressions that use functions defined in IMAS package.
So for now, it seems safe to set all three files as bound to the IMAS package.