[PyMOL] ignore_case in next PyMOL version

[Thomas H. <tho...@sc...>]

Greetings,

I like to let you know that we plan another change for the "ignore_case" setting behavior. We want to restore the old default (ignore_case=on) and introduce a new setting "ignore_case_chain=off", which will affect the "chain" and "segi" identifiers.

As you may (or should) know, we changed the default of the "ignore_case" setting in PyMOL 1.8 from "on" to "off". The rationale was to have default settings which properly support PDB files which mix upper and lower case chain identifiers (e.g. 3a0b). Users who still prefer a case insensitive selection language can put a "set ignore_case" line in their pymolrc file.

However, we now realized that this is not very practical. One reason is that too many scripts and code samples use lower case resn and name selections, fixing those historic resources is often not feasible or desirable. Another reason is that PyMOL inconsistently stores element symbols, for example chlorine is "CL" when loaded from a PDB file, but "Cl" when loaded from SDF. The logical conclusion is that PyMOL should handle chain and segi different from resn, name and elem.

See also: http://pymolwiki.org/index.php/ignore_case

Any kind of feedback regarding the planned change will be appreciated.

Cheers,
  Thomas

-- 
Thomas Holder
PyMOL Principal Developer
Schrödinger, Inc.