protected override Expression ReduceInternal()
{
var originalItemValue = Expression.Parameter(CurrentItem.Type, "foreachOriginalItem");
var originalIndex = Expression.Parameter(typeof(object), "foreachOriginalVelocityIndex");
//Need to store the enumerable in a local variable so we don't end up computing it twice (once with the TypeAs check, and again with the execution)
var localEnumerable = Expression.Parameter(typeof(IEnumerable), "foreachEnumerable");
var body = ((RenderedBlock)Body).Children;
var parts = GetParts(body);
var forEach = new TemplatedForeachExpression(
enumerable: localEnumerable,
loopVariable: CurrentItem,
loopIndex: CurrentIndex,
breakLabel: _break,
beforeAll: GetExpressionBlock(parts, ForeachSection.BeforeAll),
before: GetExpressionBlock(parts, ForeachSection.Before),
odd: GetExpressionBlock(parts, ForeachSection.Odd),
even: GetExpressionBlock(parts, ForeachSection.Even),
between: GetExpressionBlock(parts, ForeachSection.Between),
after: GetExpressionBlock(parts, ForeachSection.After),
afterAll: GetExpressionBlock(parts, ForeachSection.AfterAll),
each: GetExpressionBlock(parts, ForeachSection.Each),
noData: GetExpressionBlock(parts, ForeachSection.NoData)
);
var loopExecution = Expression.Block(
typeof(void),
new[] { originalIndex, originalItemValue },
Expression.Assign(originalItemValue, CurrentItem),
Expression.Assign(originalIndex, CurrentIndex),
forEach,
Expression.Assign(CurrentIndex, originalIndex),
Expression.Assign(CurrentItem, originalItemValue)
);
return(new TemporaryVariableScopeExpression(
localEnumerable,
Expression.Block(
Expression.Assign(localEnumerable, Expression.TypeAs(Enumerable, typeof(IEnumerable))),
Expression.IfThenElse(
Expression.Equal(localEnumerable, _nullEnumerable),
forEach.NoData ?? Constants.EmptyExpression,
loopExecution
)
)
));
}
protected virtual Expression VisitTemplatedForEach(TemplatedForeachExpression node) => base.VisitExtension(node);
