Look at how the for-each loop internally works, see How does the Java ‘for each’ loop work? for(Iterator<String> i = someList.iterator(); i.hasNext(); ) { String item = i.next(); System.out.println(item); } Each time it declares the String variable item. Hence in your case its doing essentially State state; \\and inside State state = i.next(); which obviously … Read more
Looking at the early (6th edition Unix, 1975) C manual from Dennis Ritchie’s home page, in that version function-local variables could only be declared at the beginning of a function: The function-statement is just a compound statement which may have declarations at the start. function-statement: { declaration-listopt statement-list } declaration-list is not defined (an omission), … Read more
1) Can Method Handles be used for Function Types? Scala targets JDK 5 and 6 which don’t have method handles, so it hasn’t tried to deal with that issue yet. 2) Can we get rid of the explicit declaration of “throws” type parameters? Scala doesn’t have checked exceptions. 3) Disallow @Shared on old-style loop index … Read more
These are pretty tricky constructs, and it’s tough to give clear explanations; they aren’t as straightforward as Lisp macros (or, for that matter, the relationship between Lisp’s QUOTE and EVAL). However, there’s a good, lengthy discussion available in the form of notes from Robby Villegas’s 1999 talk “Unevaluated Expressions” on Wolfram’s website. Defer is omitted … Read more
An object initializer doesn’t; a collection initializer does. It’s so that it’s applied to classes which really represent collections, rather than just arbitrary ones which have an Add method. I have to admit that every so often I’ve “implemented” IEnumerable explicitly, just to allow collection initializers – but thrown a NotImplementedException from GetEnumerator(). Note that … Read more
Any programming language which is Turing complete, and which is able to output any string (by a computable function of the string as program — this is a technical condition that is satisfied in every programming language in existence) has a quine program (and, in fact, infinitely many quine programs, and many similar curiosities) as … Read more
The other likely size for it is that of int, being the “efficient” integer type for the platform. On architectures where it makes any difference whether the implementation chooses 1 or sizeof(int) there could be a trade-off between size (but if you’re happy to waste 7 bits per bool, why shouldn’t you be happy to … Read more
using directives and include preprocessor directives are two different things. The include roughly corresponds to the CLASSPATH environment variable of Java, or the -cp option of the java virtual machine. What it does is making the types known to the compiler. Just including <string> for example will make you able to refer to std::string : … Read more
AFAIK that’s changed in C++0x. I guess it was just an oversight (considering that you can always get the partial specialization effect with more verbose code, by placing the function as a static member of a class). You might look up the relevant DR (Defect Report), if there is one. EDIT: checking this, I find … Read more
To re-iterate, type-punning through unions is perfectly fine in C (but not in C++). In contrast, using pointer casts to do so violates C99 strict aliasing and is problematic because different types may have different alignment requirements and you could raise a SIGBUS if you do it wrong. With unions, this is never a problem. … Read more