Split a comma-list of identifiers, respecting double-quoted identifiers (which may contain
commas and use "" to escape embedded quotes). Returns null when the input is not a clean
comma-list of identifiers (e.g. contains function calls or literals), so callers treat it
as an opaque expression.
Split a comma-list of identifiers, respecting double-quoted identifiers (which may contain commas and use
""to escape embedded quotes). Returnsnullwhen the input is not a clean comma-list of identifiers (e.g. contains function calls or literals), so callers treat it as an opaque expression.