Java 8 Lambdas

Post by btilly » Sun, Jun 24, 2012, 10:57 PM UTC

julian37 wrote: post #56

btilly wrote: post #49

Earlier quoted context omitted.

There is no confusion here. Once the function is passed out of the scope that it was created in, it becomes anonymous. If you disagree, demonstrate how it is at that point associated with any available identifier.

This is getting a bit tiresome, but I'll play along since your high karma leads me to believe you're genuinely confused and not a troll. The point of anonymous functions is not whether or not they will eventually be bound to an identifier, i.e. what happens with the function later on. The point is terseness in declaration: the ability to avoid having to define a full-blown function for small pieces of code that you w…

  function (x, y) {
    return x + y;
  }

Post by gouranga » Sun, Jun 24, 2012, 11:03 PM UTC

henrikschroder wrote: post #77

gouranga wrote: post #54

Earlier quoted context omitted.

I don't think that they reduce bugs at all - that's a bit of a wired assertion to make. Its not about the programmers but the architecture. To be honest, the primary use case for lambda expressions in .net is LINQ and possibly container configuration. If you use NHibernate and do not expose IEnumerable anywhere (which is required across network boundaries and encapsulation boundaries) then you just don't see it anywh…

> To be honest, the primary use case for lambda expressions in .net is LINQ Uhm, yes, if you're incapable of using delegates and writing functions that take delegates as parameters, then you'll only use lambda expressions where other people have written such functions, for example in LINQ or the generic collections in the framework. But if you can use delegates, and if you can use lambda expressions, they're a wonder…

Post by gouranga » Sun, Jun 24, 2012, 11:18 PM UTC

thomasz wrote: post #90

gouranga wrote: post #73

Earlier quoted context omitted.

Not necessarily. collection.Where(s => s.Property.Name == "Blah!").Single(); 4 hand grenades waiting to go off in that expression. Try and spot them. We have a 670kloc platform that doesn't have a single one in it (it's still .Net 2.0). 450 domain objects, 1000+ NH criteria queries and about 650 aspx pages...

I don't see any pitfalls that wouldn't arise with imperative techniques. Well, Single() throws if there is no or more than one item with the property name "Blah!" in the collection, but if you just want the first one or none you should use FirstOrDefault() anyway. The point is that you need to write roughly a dozen lines with more room for hand grenades to reproduce that functionality with imperative constructs: Thin…

    public Thing GetItemWithName(ICollection collection)
    {
        Thing output;
        int found;

        // preconditions
        Check.IsNotNull(collection, "collection was null");

        foreach(var item in collection)
        {
            // ref checks
            Check.IsNotNull(item, "item was null");
            Check.IsNotNull(item.Property, "item.Property was null");
            Check.IsNotNullOrWhiteSpace(item.Property.Name, "item.Property.Name was null or whitespace");
      
            if (string.Compare(item.Property.Name, "Blah!", StringComparison.InvariantCultureIgnoreCase) != 0)
                continue;
            
            found++;

            // rule check
            Check.IsTrue(found