Statifier.Validator.Checks.Param (Statifier v2.15.0)

Spec 5.7: "A conformant SCXML document MUST specify either the 'expr' attribute of <param> or the 'location' attribute, but MUST NOT specify both." Reports {:param_expr_and_location, name} when both are present and {:param_no_value, name} when neither is, both at the <param> element's own location.

lib/statifier/document/param.ex makes expr and param_location both nilable and representable at once precisely so this check can report the shape rather than lowering refusing to build it - the same division of labour Checks.Content has with <content>.

Three places hold a %Statifier.Document.Param{}: a <final>'s <donedata><param> (Statifier.Document.Donedata), any state's <invoke><param> (Statifier.Document.Invoke) and any <send>'s own <param> children (Statifier.Document.Send), so this check walks all three. The rule is the same for each, since spec 5.7 states it on <param> rather than on whichever parent holds it, and so are the two reasons: a host matching on :param_no_value or :param_expr_and_location sees one vocabulary whatever the parent. A <send> sits in executable content rather than on a state, so its arm reaches every <send> through Checks.Send's own walk (every block a <send> can appear in, <if> and <foreach> bodies and <finalize> included) rather than a second walker that could disagree with it.

Summary

Functions

check(document, context)

Walks every <final>'s <donedata><param>, every state's <invoke><param> and every <send>'s <param> in the document and returns a :param_expr_and_location or :param_no_value error for each one whose expr and location attributes violate spec 5.7's exactly-one rule. Returns [] when every <param> in the document specifies exactly one.

Functions

check(document, context)

@spec check(
  document :: Statifier.Document.t(),
  context :: Statifier.Validator.Context.t()
) :: [
  Statifier.Validator.Error.t()
]