id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
815	chain-level zone atomspec not yet implemented	Elaine Meng	Conrad Huang	"“/<“ doesn’t promote to chain… gives the same set of atoms as “@<“

Example:
open 1zik
show
la :69 res
sel :69 /<5

Conrad:
The chain zone atomspec was not implemented because (in the implementation) the Chains class is completely different than Residues and Structures.  We can convert between Atoms and Residues with atoms.unique_residues and residues.atoms.  But there is no equivalent atoms.unique_chains or chains.atoms.

Elaine:
One contributing factor might be that there could be differing definitions of chain:  same molecule/biopolymer (based on covalent bonding) or everything with the same chain ID.  I guess I’d expect the latter for zone atomspec since the “/“ symbol is being used, but for selection up-down arrow cascades it’s nice to have both levels like we have in Chimera.

Eric:
That’s probably the sticking point — “chains” only cover the polymeric atoms, not other atoms with that chain ID.

Eric (earlier message):
chains<->atoms is just a “two level” conversion, i.e. chains.existing_residues.atoms and atoms.unique_residues.unique_chains.
 "	defect	closed	major		Command Line		fixed						all	ChimeraX