public static Expression WalkGraph(Expression op, IGraphInspector inspector)
{
// The pre walk call
op = inspector.OnBeforeWalk(op);
ExpressionType type = op.Type;
switch (type) {
case ExpressionType.Function:
InspectParamList(inspector, op, "param_count", "arg");
break;
case ExpressionType.Select:
InspectParam(inspector, op, "join");
InspectParam(inspector, op, "filter");
InspectParam(inspector, op, "havingfilter");
InspectParamList(inspector, op, "out_count", "out");
InspectParamList(inspector, op, "groupby_count", "groupby");
InspectParamList(inspector, op, "orderby_count", "orderby");
break;
case ExpressionType.Join:
InspectParam(inspector, op, "left");
InspectParam(inspector, op, "right");
InspectParam(inspector, op, "filter");
break;
// Single passthrough
case ExpressionType.AliasTableName:
case ExpressionType.AliasVariableName:
InspectParam(inspector, op, "child");
break;
case ExpressionType.Filter:
InspectParam(inspector, op, "child");
InspectParam(inspector, op, "filter");
break;
// Terminators
case ExpressionType.FetchVariable:
case ExpressionType.FetchStatic:
case ExpressionType.FetchParameter:
case ExpressionType.FetchGlob:
case ExpressionType.FetchTable:
break;
default:
throw new ArgumentException("Unknown operation " + op.Type);
}
// The post expression call
op = inspector.OnAfterWalk(op);
// Return the operation
return op;
}
private static void InspectParamList(IGraphInspector inspector, Expression op, string size_arg, string pre_arg)
{
int sz = (int)op.GetArgument(size_arg);
for (int i = 0; i < sz; ++i) {
InspectParam(inspector, op, pre_arg + i);
}
}
private static void InspectParam(IGraphInspector inspector, Expression expression, string paramArg)
{
object paramVal = expression.GetArgument(paramArg);
if (paramVal != null && paramVal is Expression) {
Expression inspected = paramVal as Expression;
expression.SetArgument(paramArg, WalkGraph(inspected, inspector));
}
}
