Method AddQualifier

interpreter/attributes.go:499–526

AddQualifier adds a qualifier to each possible attribute variant, and also creates a new namespaced variable from the qualified value. The algorithm for building the maybe attribute is as follows: 1. Create a maybe attribute from a simple identifier when it occurs in a parsed-only expression mb

(qual Qualifier)

//
// If none of the attributes within the maybe resolves a value, the result is an error.
func (a *maybeAttribute) AddQualifier(qual Qualifier) (Attribute, error) {
	str := ""
	isStr := false
	cq, isConst := qual.(ConstantQualifier)
	if isConst {
		str, isStr = cq.Value().Value().(string)
	}
	var augmentedNames []string
	// First add the qualifier to all existing attributes in the oneof.
	for _, attr := range a.attrs {
		if isStr && len(attr.Qualifiers()) == 0 {
			candidateVars := attr.CandidateVariableNames()
			augmentedNames = make([]string, len(candidateVars))
			for i, name := range candidateVars {
				augmentedNames[i] = fmt.Sprintf("%s.%s", name, str)
			}
		}
		_, err := attr.AddQualifier(qual)
		if err != nil {
			return nil, err
		}
	}
	// Next, ensure the most specific variable / type reference is searched first.
	if len(augmentedNames) != 0 {
		a.attrs = append([]NamespacedAttribute{a.fac.AbsoluteAttribute(qual.ID(), augmentedNames...)}, a.attrs...)
	}
	return a, nil
}

// Qualify is an implementation of the Qualifier interface method.
func (a *maybeAttribute) Qualify(vars Activation, obj any) (any, error) {