While a block is just a piece of code that can be composed by statements and declarations but nothing else, a closure is a real first-class object, a real variable that has a block as its value. The main difference is that a block simply groups instructions together (for example the body of a while … Read more
In languages such as C, C++, C#, Java, IF is a statement implemented as a reserved word, part of the core of the language. In programming languages of the LISP family (Scheme comes to mind) IF is an expression (meaning that it returns a value) and is implemented as a special form. On the other … Read more
Namespace is a way to implement scope. In Java (or C) the compiler determines where a variable is visible through static scope analysis. In C, scope is either the body of a function or it’s global or it’s external. The compiler reasons this out for you and resolves each variable name based on scope rules. … Read more
Personally, I feel that the “expressiveness” of a language really comes down to how clearly the language constructs can “express” the developer’s intentions. For example, I feel that C# (especially LINQ via C# 3+) is becoming much more expressive. This LINQ statement is a great example: var results = collection.Where(item => item > 5); Without … Read more
Warning: this is a really long explanation, but hopefully it really explains not only what SFINAE does, but gives some idea of when and why you might use it. Okay, to explain this we probably need to back up and explain templates a bit. As we all know, Python uses what’s commonly referred to as … Read more
Encapsulation is a way to achieve “information hiding” so, following your example, you don’t “need to know the internal working of the mobile phone to operate” with it. You have an interface to use the device behaviour without knowing implementation details. Abstraction on the other side, can be explained as the capability to use the … Read more
Haha! Thanks to my Google-fu, I have found an SO answer that may interest you. Basically, the answer is going against the “don’t overload operators unless you really have to” argument by overloading the bitwise-OR operator to provide shell-like piping, resulting in Python code like this: for i in xrange(2,100) | sieve(2) | sieve(3) | … Read more
Boo is a statically typed language for the Common Language Infrastructure (aka. the Microsoft .NET platform). The syntax is highly inspired by Python, and hashes/lists/array are part of the syntax: i = 5 if i > 5: print “i is greater than 5.” else: print “i is less than or equal to 5.” hash = … Read more
There’s a simple ad hoc proof for this. Since you can build a Turing complete language using strictly iterative structures and a Turing complete language using only recursive structures, then the two are therefore equivalent.
Yes. In general any literal string, identifier, or other constant string in JS source is interned. However implementation details (exactly what is interned for instance) varies, as well as when the interning occurs. Note that a string value is not the same as a String Object though, String Objects are not interned because that would … Read more