Postgresql historically doesn’t support procedural code at the command level – only within functions. However, in Postgresql 9, support has been added to execute an inline code block that effectively supports something like this, although the syntax is perhaps a bit odd, and there are many restrictions compared to what you can do with SQL … Read more
The issue has nothing to do with thread safety, really. There’s a simple, straightforward answer to why instance variables can always be captured: this is always effectively final. That is, there is always one known fixed object at the time of the creation of a lambda accessing an instance variable. Remember that an instance variable … Read more
As an additional information for future readers, starting from ruby 2.1.0 you can using binding.local_variable_get and binding.local_variable_set: def foo a = 1 b = binding b.local_variable_set(:a, 2) # set existing local variable `a’ b.local_variable_set(:c, 3) # create new local variable `c’ # `c’ exists only in binding. b.local_variable_get(:a) #=> 2 b.local_variable_get(:c) #=> 3 p a … Read more
MySQL has two different types of variable: local variables (which are not prefixed by @) are strongly typed and scoped to the stored program block in which they are declared. Note that, as documented under DECLARE Syntax: DECLARE is permitted only inside a BEGIN … END compound statement and must be at its start, before … Read more
local_variables It outputs array of symbols, presenting variables. In your case: [:a, :b]
You have just stumbled on a js “feature” called hoisting var myname = “global”; // global variable function func() { alert(myname); // “undefined” var myname = “local”; alert(myname); // “local” } func(); In this code when you define func the compiler looks at the function body. It sees that you are declaring a variable called … Read more
var asks the compiler to infer the type of the variable from the type of the initializer, and the natural type of 42 is int. So number will be an int. That is what the JLS example says: var a = 1; // a has type ‘int’ And I would be surprised if it worked … Read more
Class methods don’t really exist in Ruby, they are just singleton methods of the class object. Singleton methods don’t really exist, either, they are just ordinary instance methods of the object’s singleton class. Since you already know how to define instance methods (using Module#define_method), you already know everything you need to know. You just need … Read more
Firstly, the part about variables being “overridden” – final has two very different meanings. For classes and methods, it’s about inheritance; for variables it’s about being read-only. There’s one important “feature” of final local variables: they can be used in local (typically anonymous) inner classes. Non-final local variables can’t be. That’s the primary use of … Read more
Yes, the lifetime of a local variable is within the scope({,}) in which it is created. Local variables have automatic or local storage. Automatic because they are automatically destroyed once the scope within which they are created ends. However, What you have here is a string literal, which is allocated in an implementation-defined read-only memory. … Read more