Hi Kevin,
On 9/19/2018 12:31 PM, Kevin Bourrillion wrote:
In other cases, it looks like you're gaining a very /small/ amount of
syntactic conciseness (mostly omitting `return`) and not much else? Is
there any actual /conceptual/ simplicity or clarity being gained?
Let me focus on the single expression form. The argument we've made is:
statement lambdas have a concise form, expression lambdas, that improves
clarity, and method bodies are like statement lambdas, so they should
have a concise form too. Maybe that's stretching the connection between
statement lambdas and method bodies too thin, but it's a fair starting
point. Perhaps the outcome will be classes with a mishmash of method
body forms, where the jumping between {} and -> acts to hurt readability
overall even if individual methods are simpler. (Shades of switch
expressions having both : and -> cases.) And, empirically, perhaps there
are very few method bodies in your codebase simple enough to adopt the
-> form. (Data welcome.)
Alex
JEPs don't seem to often include any discussion of what the costs of the
feature change. So evaluating benefit vs. cost is not easy. For example,
in this case, it becomes harder to understand and explain what a method
reference even /is/. I've been saying "it's just a lambda expression",
but either that's gone, or it's now becoming harder to understand and
explain what a lambda expression is.
I think moral-hazard arguments also deserve a bit of thought.
public A b(C c, D d, E e, F f) { return g.h(c, d, e, f); }
If I forgot an "if e is empty, throw" check in here, I'll just insert
it. But if it was this:
public A b(C c, D d, E e, F f) = g::h;
I'm probably less likely to do that.
This is a bit similar to why our style guide requires braces around
single-statement if blocks. It's too annoying to deal with inserting
them and removing them all the time as conditions change.
Perhaps these costs don't add up to anything massive, but we should
still get a fix on them because if it turns out the benefits
/also/ don't add up to something massive then....?
I hope this is helpful.
On Wed, Sep 19, 2018 at 11:58 AM <mark.reinh...@oracle.com
<mailto:mark.reinh...@oracle.com>> wrote:
2018/9/19 11:42:16 -0700, alex.buck...@oracle.com
<mailto:alex.buck...@oracle.com>:
> https://bugs.openjdk.java.net/browse/JDK-8209434
Or, more readably: http://openjdk.java.net/jeps/8209434
- Mark
--
Kevin Bourrillion | Java Librarian | Google, Inc. |kev...@google.com
<mailto:kev...@google.com>
