/// <summary>
/// Build a method for accessing a variable in a context.
/// </summary>
/// <param name="environment">
/// <see cref="Aplus">Aplus</see>, which contains the variables.
/// </param>
/// <param name="contextParts">
/// (context, variablename), as returned from <see cref="CreateContextParts"/> method.
/// </param>
/// <returns>Expression tree of a Lambda expression.</returns>
internal static DLR.Expression <Func <AType> > BuildVariableAccessMethod(Aplus environment,
string[] contextParts)
{
DLR.Expression <Func <AType> > lambda =
DLR.Expression.Lambda <Func <AType> >(
// Convert the variable to an AType
DLR.Expression.Dynamic(
environment.ConvertBinder(typeof(AType)),
typeof(AType),
// Access the variable
VariableHelper.GetVariable(
environment,
DLR.Expression.Constant(environment.Context),
contextParts
)
)
);
return(lambda);
}
/// <summary>
/// Build a method for accessing a variable in a context.
/// </summary>
/// <param name="environment">
/// <see cref="Aplus">Aplus</see>, which contains the variables.
/// </param>
/// <param name="contextParts">
/// (context, variablename), as returned from <see cref="CreateContextParts"/> method.
/// </param>
/// <returns>Expression tree of a Lambda expression.</returns>
internal static DLR.Expression<Func<AType>> BuildVariableAccessMethod(Aplus environment,
string[] contextParts)
{
DLR.Expression<Func<AType>> lambda =
DLR.Expression.Lambda<Func<AType>>(
// Convert the variable to an AType
DLR.Expression.Dynamic(
environment.ConvertBinder(typeof(AType)),
typeof(AType),
// Access the variable
VariableHelper.GetVariable(
environment,
DLR.Expression.Constant(environment.Context),
contextParts
)
)
);
return lambda;
}
/// <summary>
/// Wraps the expression inside a Dynamic cast to AType
/// </summary>
/// <param name="expression">Expression to cast.</param>
/// <param name="runtime"></param>
/// <returns></returns>
internal static DLR.DynamicExpression ToAType(this DLR.Expression expression, Aplus runtime)
{
return(DLR.Expression.Dynamic(runtime.ConvertBinder(typeof(AType)), typeof(AType), expression));
}
public override DLR.Expression Generate(AplusScope scope)
{
DLR.Expression result;
Aplus runtime = scope.GetRuntime();
if (this.Type == IdentifierType.SystemName && runtime.SystemFunctions.ContainsKey(this.Name))
{
// Check if the name is a system function's name and we have such system function
// and return it
result = DLR.Expression.Constant(runtime.SystemFunctions[this.Name]);
return(result);
}
DLR.Expression variableContainer = scope.GetModuleExpression();
string[] contextParts = CreateContextNames(runtime.CurrentContext);
// Check if the scope is a method
if (scope.IsMethod)
{
DLR.Expression parentVariableContainer = scope.Parent.GetModuleExpression();
// Check for variable in method scope
// (maybe the variable is defined in the method header)
DLR.Expression localVariable = scope.FindIdentifier(this.variableName);
if (localVariable != null)
{
// Found a variable defined in the method's header
return(localVariable);
}
if (this.type == IdentifierType.UnQualifiedName)
{
// 1). we check if the variable exists in the function's scope
// 2). check if the variable exits in the current context (error if not found)
//
// if(((IDictionary<String, Object>)($FunctionScope).ContainsKey($VARIABLE))
// {
// return $FunctionScope.$VARIABLE;
// }
// else
// {
// return $GlobalScope.$VARIABLE
// }
//
DLR.Expression getVariable = DLR.Expression.Condition(
DLR.Expression.Call(
DLR.Expression.Convert(variableContainer, typeof(IDictionary <string, object>)),
typeof(IDictionary <string, object>).GetMethod("ContainsKey"),
DLR.Expression.Constant(this.variableName)
),
// True case:
DLR.Expression.Dynamic(
runtime.GetMemberBinder(this.variableName),
typeof(object),
variableContainer
),
// False case:
BuildGlobalAccessor(scope, runtime, parentVariableContainer, contextParts),
// resulting type
typeof(object)
);
result = DLR.Expression.Dynamic(
runtime.ConvertBinder(typeof(AType)),
typeof(AType),
getVariable
);
return(result);
}
else if (this.type == IdentifierType.QualifiedName)
{
// Found a variable like: .var
// for this check the parent's variables
variableContainer = parentVariableContainer;
// Fallback to the non-method case
}
}
result = Tools.CloneMemoryMappedFile(BuildGlobalAccessor(scope, runtime, variableContainer, contextParts));
return(result);
}