Default merge behavior for a koma_ts attribute — default_koma_attr

Used by merge_koma_attrs() for any attribute without a policy registered via set_koma_attr_policy(). NULL operands are passed through unchanged; otherwise the two values must be identical (per base::all.equal()) or the merge errors, since there is no generic way to combine two different metadata values (e.g. two different anker anchors) without attribute-specific knowledge of what the operation means.

Usage

default_koma_attr_merge(left, right, attr, op = NULL, template = NULL)

Arguments

left: The first operand's attribute value, or NULL if absent.
right: The second operand's attribute value, or NULL if absent.
attr: Name of the attribute, used in the error message.
op: Name of the arithmetic operation being performed (e.g. "-"), used in the error message.
template: Unused; accepted for signature compatibility with handlers registered via set_koma_attr_policy().

Value

left (or right, when left is NULL) if the values match or one side is absent. Errors otherwise.