public static Expression ForEach(ParameterExpression item, Expression source, Expression body)
{
if (!typeof(IEnumerable).IsAssignableFrom(source.Type))
{
throw new InvalidOperationException($"{source.Type} does not implement IEnumerable and cannot be iterated using foreach");
}
ParameterExpression enumerator = Expression.Parameter(typeof(IEnumerator), "enumerator");
LabelTarget forEachEnd = Expression.Label();
return(Expression.Block(
new[] { item, enumerator },
Expression.Assign(
enumerator,
Expression.Call(source, EnumerableMembers.GetEnumerator())
),
Expression.Loop(
Expression.IfThenElse(
Expression.Call(enumerator, EnumerableMembers.MoveNext()),
Expression.Block(
Expression.Assign(item, Expression.Convert(Expression.Property(enumerator, EnumerableMembers.Current()), item.Type)),
body
),
Expression.Break(forEachEnd)
),
forEachEnd
)
));
}
private Expression <Func <IDiff <TType>, IDiff <TType>, IConflictContainer, List <IDiffItem> > > Compile()
{
ParameterExpression left = Expression.Parameter(typeof(IDiff <TType>), "left");
ParameterExpression right = Expression.Parameter(typeof(IDiff <TType>), "right");
ParameterExpression conflicts = Expression.Parameter(typeof(IConflictContainer), "ret");
ParameterExpression ret = Expression.Parameter(typeof(List <IDiffItem>), "ret");
ParameterExpression leftEnumerator = Expression.Parameter(typeof(IEnumerator <IDiffItem>), "leftEnumerator");
ParameterExpression leftSomeLeft = Expression.Parameter(typeof(bool), "leftSomeLeft");
ParameterExpression rightEnumerator = Expression.Parameter(typeof(IEnumerator <IDiffItem>), "rightEnumerator");
ParameterExpression rightSomeLeft = Expression.Parameter(typeof(bool), "rightSomeLeft");
return(Expression.Lambda <Func <IDiff <TType>, IDiff <TType>, IConflictContainer, List <IDiffItem> > >(
Expression.Block(
new[] { ret, leftEnumerator, leftSomeLeft, rightEnumerator, rightSomeLeft },
Expression.Assign(
ret,
Expression.New(
ListMembers.NewWithCount(typeof(IDiffItem)),
Expression.Add(
Expression.Property(left, DiffMembers.Count()),
Expression.Property(right, DiffMembers.Count())
)
)
),
Expression.Assign(
leftEnumerator,
Expression.Call(left, EnumerableMembers.GetEnumerator(typeof(IDiffItem)))
),
Expression.Assign(
rightEnumerator,
Expression.Call(right, EnumerableMembers.GetEnumerator(typeof(IDiffItem)))
),
this.MoveEnumerator(leftEnumerator, leftSomeLeft),
this.MoveEnumerator(rightEnumerator, rightSomeLeft),
Expression.Block(Class <TType> .Properties.Select(x => this.EvaluateProperty(leftEnumerator, leftSomeLeft, rightEnumerator, rightSomeLeft, conflicts, ret, x))),
ret
),
left, right, conflicts
));
}