protected override Expression VisitConstant(ConstantExpression node)
{
var site = node.Value as CallSite;
if (site != null)
{
return(RewriteCallSite(site));
}
var exprSerializable = node.Value as IExpressionSerializable;
if (exprSerializable != null)
{
return(Visit(exprSerializable.CreateExpression()));
}
var symbols = node.Value as SymbolId[];
if (symbols != null)
{
return(Expression.NewArrayInit(
typeof(SymbolId),
new ReadOnlyCollection <Expression>(
symbols.Map(s => SymbolConstantExpression.GetExpression(s))
)
));
}
return(base.VisitConstant(node));
}
protected override Expression VisitExtension(Expression node)
{
if (node.NodeType == ExpressionType.Dynamic)
{
// the node was dynamic, the dynamic nodes were removed,
// we now need to rewrite any call sites.
return(VisitDynamic((DynamicExpression)node));
}
SymbolConstantExpression symbol = node as SymbolConstantExpression;
if (symbol != null)
{
SymbolId id = symbol.Value;
if (id == SymbolId.Empty)
{
return(Expression.Field(null, typeof(SymbolId).GetField("Empty")));
}
FieldBuilderExpression value;
if (!_indirectSymbolIds.TryGetValue(id, out value))
{
// create field, emit fix-up...
if (_symbolGen == null)
{
_symbolGen = new TypeGen(_typeGen.AssemblyGen, ((ModuleBuilder)_typeGen.TypeBuilder.Module).DefineType("Symbols" + Interlocked.Increment(ref _id)));
#if SILVERLIGHT
_finishedSymbolType = new StrongBox <Type>();
#endif
}
FieldBuilder field = _symbolGen.AddStaticField(typeof(SymbolId), FieldAttributes.Public, SymbolTable.IdToString(id));
ILGen init = _symbolGen.TypeInitializer;
if (_indirectSymbolIds.Count == 0)
{
init.EmitType(_symbolGen.TypeBuilder);
init.EmitCall(typeof(ScriptingRuntimeHelpers), "InitializeSymbols");
}
#if SILVERLIGHT
_indirectSymbolIds[id] = value = new FieldBuilderExpression(field, _finishedSymbolType);
#else
_indirectSymbolIds[id] = value = new FieldBuilderExpression(field);
#endif
}
Debug.Assert(value != null);
return(value);
}
return(Visit(node.Reduce()));
}
