Three choices: Don't change (see comment to see how that looks) Change to consistent use of "and" Change to consistent use of comma We discussed this with FSH users on the 6/11/2020 call, and the clear preference was for #2.  Therefore, the proposed resolution is to replace comma with "and" in rules, as follows: path rules:  * path1 and path2 and path3... flag1 flag2 .. . invariant rules:   * path obeys invariant1 and invariant2, ..   contains rules:   * extension-path contains local-name1 card1 flags1  and local-name2 card2 flags2 .. {{}} includes rules with filters:  * codes from system codesystem where filter1 and filter2 and ...  The proposed disposition is favored because: It is consistent with the use of "or" in FSH It is easier to understand and read It keeps comma for other future purposes (e.g., lists). There are probably not many invariant rules that will need to be changed. The main impact will be flag rules.