String validation

[ahy3nz]

Describe the behavior you would like added to mBuild
After atomtyping with an FFXML, the resultant structure.atoms might have names that are very long strings. When writing to a fixed-column-width format, these names get truncated, which could raise issues when trying to perform a simulation

Describe the solution you'd like
Some string validation checks. The best solution isn't apparent because we use parmed's gro/pdb writers, but could we do some iteration through a pmd.Structure or mb.Compound to check string lengths?

Describe alternatives you've considered
While this isn't an absolutely essential feature, other workarounds could include making sure someone's FFXML will indeed fit their file format constraints, preventing the issue of too-long-strings. For example, making sure every type, class, element XML attribute is within the 4-char limit for PDB atoms

[mattwthompson]

Correct me if I'm confused, but this seems like more of a backend issue?

[ahy3nz]

I wasn't sure where to put this issue - the writers are in mbuild, but the validation would mainly be on parmed structures post-ff-application. Maybe there's not some code/module we can put to address this, but just observe this as a potential obstacle for users interested in using mosdef with their workflows

[CalCraven]

This issue will in the future be a GMSO one as writing through ParmED will be deprecated. This gives us more control over these tests, which should be on the writer end of things.