let.cs

{DispatchTypes.Method, "let", (e, s) =>
    e.Arguments[0] is VectorExpression
        ? new SymbolTable(s).Let(ns => ((VectorExpression) e.Arguments[0]).Elements
              .SelectMany(_ => _.List(":").Let(l => l != null
                  ? new [] { l.First(), Expression.Default(((TypeCandidateExpression) l.Last().Reduce(s)).ElectedType), }
                  : EnumerableEx.Return(_)
              ))
              .Share(_ => _.Zip(_, (i, v) => ((IdentifierExpression) i).Name.Let(n =>
                  v.Reduce(ns).Apply(r => ns.Add(n, Expression.Variable(r.Type, n)))
              )))
              .ToArray()
              .Let(_ => Expression.Block(
                  ns.Literals.Values.OfType<ParameterExpression>(),
                  e.Arguments
                      .Skip(1)
                      .ReduceAll(ns)
                      .StartWith(ns.Literals.Values.Zip(_, Expression.Assign).ToArray())
              ))
          )
        : Expression.Block(e.Arguments.ReduceAll(s))
},