// Trait defines an API trait. A trait encapsulates arbitrary DSL that gets executed wherever the
// trait is called via the UseTrait function.
func Trait(name string, val ...func()) {
var ver *design.APIVersionDefinition
if a, ok := apiDefinition(false); ok {
ver = a.APIVersionDefinition
} else if v, ok := versionDefinition(true); ok {
ver = v
}
if len(val) < 1 {
ReportError("missing trait DSL for %s", name)
return
} else if len(val) > 1 {
ReportError("too many arguments given to Trait")
return
}
if ver == nil {
return
}
if _, ok := ver.Traits[name]; ok {
ReportError("multiple definitions for trait %s%s", name, ver.Context())
return
}
trait := &design.TraitDefinition{Name: name, DSLFunc: val[0]}
if ver.Traits == nil {
ver.Traits = make(map[string]*design.TraitDefinition)
}
ver.Traits[name] = trait
}
