public virtual Binding BindSymbolForWrite(BindingRequest request)
{
var scope = request.Thread.CurrentScope;
var existingSlot = scope.Info.GetSlot(request.Symbol);
//1. If new only, check it does not exist yet, create and return it
if (request.Flags.IsSet(BindingRequestFlags.NewOnly))
{
if (existingSlot != null)
{
request.Thread.ThrowScriptError("Variable {0} already exists.", request.Symbol);
}
var newSlot = scope.AddSlot(request.Symbol);
return(new SlotBinding(newSlot, request.FromNode, request.FromScopeInfo));
}
//2. If exists, then return it
if (existingSlot != null && request.Flags.IsSet(BindingRequestFlags.ExistingOrNew))
{
//TODO: For external client, check that slot is actually public or exported
return(new SlotBinding(existingSlot, request.FromNode, request.FromScopeInfo));
}
//3. Check external module imports
foreach (var imp in request.FromModule.Imports)
{
var result = imp.Bind(request);
if (result != null)
{
return(result);
}
}
//4. If nothing found, create new slot in current scope
if (request.Flags.IsSet(BindingRequestFlags.ExistingOrNew))
{
var newSlot = scope.AddSlot(request.Symbol);
return(new SlotBinding(newSlot, request.FromNode, request.FromScopeInfo));
}
//5. Check built-in methods
var builtIn = BuiltIns.Bind(request);
if (builtIn != null)
{
return(builtIn);
}
//6. If still not found, return null.
return(null);
}
public virtual Binding BindSymbolForRead(BindingRequest request)
{
var symbol = request.Symbol;
// First check current and enclosing scopes
var currScope = request.Thread.CurrentScope;
do
{
var existingSlot = currScope.Info.GetSlot(symbol);
if (existingSlot != null)
{
return(new SlotBinding(existingSlot, request.FromNode, request.FromScopeInfo));
}
currScope = currScope.Parent;
} while (currScope != null);
// If not found, check imports
foreach (var imp in request.FromModule.Imports)
{
var result = imp.Bind(request);
if (result != null)
{
return(result);
}
}
// Check built-in modules
var builtIn = BuiltIns.Bind(request);
if (builtIn != null)
{
return(builtIn);
}
// if not found, return null
return(null);
}