public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
if (variableType == null)
{
throw new Exception("Variable type not yet set. Cannot create a VariableReference of unknown type");
}
return(new[] { VariableReference.Create(variableType, (value as string) ?? ""), Binding.DoNothing }); // Send DoNothing as the binding that was used to get the type so that we do not set it
}
/// <summary>
/// Compiles the entries in the given Program into delegates.
/// Returns the delegates themselves and the delegate signatures (excluding the context parameter).
/// </summary>
private FunctionStore CompileEntryDelegates(VisualProgram program)
{
var progEntryNodes = program.Nodes.OfType <VisualEntry>().ToDictionary(ve => ve.VisualEntryId, ve => ve);
return(program.Environment.EntryDefinitions.ToDictionary(
entry => entry.Key,
entry => {
// If the program does not contain this entry node OR it exists but is not connected to any statements, then return no delegate
if (!progEntryNodes.TryGetValue(entry.Value.Id, out var startNode) || !startNode.FirstStatement.HasValue)
{
return null;
}
// Create a parameter for each expected/defined parameter
var parameters = entry.Value.Parameters.Map(Expression.Parameter);
// Compile and return the lambda
return Expression.Lambda(
Expression.Block(
// Before doing the main body of the entry function, make expressions to copy the incoming parameters to variables
startNode.ParameterMap
.Where(mapping => !string.IsNullOrWhiteSpace(mapping.Value)) // Exclude any that don't actually map to anything
.Select(p => VariableAccessorFactory.CreateSetterExpression(
program,
VariableReference.Create(entry.Value.Parameters[p.Key], p.Value),
parameters[p.Key]
)
).Concat(
// Then do the actual main body
NodeUtils.FlattenExpressions(program, startNode.FirstStatement)
)
),
// All lambdas will get a context parameter
// We also pass the defined parameters to the lambda so it knows what types to expect and what signature to have.
// This needs to happen regardless or not of whether the parameters are actually used by the entry function as this determines the delegate's signature.
new[] { program.Variables.compiledInstanceParameter }.Concat(parameters)
).Compile();
},
StringComparer.OrdinalIgnoreCase
));
}