private Expression Rewrite(CodeContextScopeExpression ccs)
{
Expression saved = _context;
ParameterExpression nested = Expression.Variable(typeof(CodeContext), "$frame");
// rewrite body with nested context
_context = nested;
Expression body = Visit(ccs.Body);
_context = saved;
// wrap the body in a scope that initializes the nested context
return(AstUtils.AddScopedVariable(body, nested, Visit(ccs.NewContext)));
}
protected override Expression VisitExtension(Expression node)
{
if (node is YieldExpression ||
node is GeneratorExpression ||
node is FinallyFlowControlExpression)
{
// These should be rewritten last, when doing finaly compilation
// for now, just walk them so we can find other nodes
return(base.VisitExtension(node));
}
GlobalVariableExpression global = node as GlobalVariableExpression;
if (global != null)
{
return(RewriteGet(global));
}
CodeContextExpression cc = node as CodeContextExpression;
if (cc != null)
{
return(_context);
}
CodeContextScopeExpression ccs = node as CodeContextScopeExpression;
if (ccs != null)
{
return(Rewrite(ccs));
}
AssignmentExtensionExpression aee = node as AssignmentExtensionExpression;
if (aee != null)
{
return(Rewrite(aee));
}
// Must remove extension nodes because they could contain
// one of the above node types. See, e.g. DeleteUnboundExpression
return(Visit(node.ReduceExtensions()));
}
