jadams-tresys commented on a change in pull request #450:
URL: https://github.com/apache/incubator-daffodil/pull/450#discussion_r539439407
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File path:
daffodil-runtime1/src/main/scala/org/apache/daffodil/processors/VariableMap1.scala
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@@ -232,19 +345,33 @@ class VariableMap private(vTable: Map[GlobalQName,
MStackOf[VariableInstance]])
*/
def readVariable(vrd: VariableRuntimeData, referringContext: ThrowsSDE,
maybePstate: Maybe[ParseOrUnparseState]): DataValuePrimitive = {
val varQName = vrd.globalQName
- val stack = vTable.get(varQName)
- if (stack.isDefined) {
- val variable = stack.get.top
- variable.state match {
- case VariableRead if (variable.value.isDefined) =>
variable.value.getNonNullable
- case VariableDefined | VariableSet if (variable.value.isDefined) => {
+ val abuf = vTable.get(varQName)
+ if (abuf.isDefined) {
+ val variable = abuf.get.last
+ (variable.state, variable.value.isDefined,
variable.defaultValueExpr.isDefined) match {
+ case (VariableRead, true, _) => variable.value.getNonNullable
+ case (VariableDefined | VariableSet, true, _) => {
if (maybePstate.isDefined && maybePstate.get.isInstanceOf[PState])
maybePstate.get.asInstanceOf[PState].markVariableRead(vrd)
variable.setState(VariableRead)
variable.value.getNonNullable
}
- case _ => throw new VariableHasNoValue(varQName, vrd)
+ case (VariableDefined, false, true) => {
+ Assert.invariant(maybePstate.isDefined)
+ variable.setState(VariableInProcess)
+ val pstate = maybePstate.get
+ val res =
DataValue.unsafeFromAnyRef(variable.defaultValueExpr.get.evaluate(pstate))
+
+ // Need to update the variable's value with the result of the
+ // expression
+ variable.setState(VariableRead)
+ variable.setValue(res)
+
+ res
Review comment:
So this case here is really only for the case where we have a
defineVariable with a default value expression that references another variable
with a default value expression. So, what happens is when we call the
forceExpressoinEvaluations at the start of parsing, it evaluates the top level
variable default value expression, which then calls readVariable for the
variable that it references, which then needs it's expression evaluated at that
time. I'll add a comment to this case explaining what is happening when this
case is hit.
This isn't an issue for newVariableInstance, as we do no need to postpone
the evaluation of expressions because the VariableMap alreadys exists by the
time we would run into any newVariableInstance expressions.
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