In CMD, ‘&&’ means “execute command 1, and if it succeeds, execute command 2”. I have used it for things like: build && run_tests In PowerShell, the closest thing you can do is: (build) -and (run_tests) It has the same logic, but the output text from the commands is lost. Maybe it is good enough … Read more
The w3 org said: By default, SGML requires that all attribute values be delimited using either double quotation marks (ASCII decimal 34) or single quotation marks (ASCII decimal 39). Single quote marks can be included within the attribute value when the value is delimited by double quote marks, and vice versa. Authors may also use … Read more
List of Block Declaration Syntaxes Throughout, let return_type be the type of object/primitive/etc. you’d like to return (commonly void) blockName be the variable name of the block you’re creating var_type be the type object/primitive/etc. you’d like to pass as an argument (leave blank for no parameters) varName be the variable name of the given parameter … Read more
The code essentially calls an empty lambda. Let’s start from the beginning: [](){} is an empty lambda expression. Then, in C and C++, you can wrap expressions in parens and they behave exactly the same† as if written without them, so that’s what the first pair of parens around the lambda does. We’re now at … Read more
James Gosling created the original JVM with support of goto statements, but then he removed this feature as needless. The main reason goto is unnecessary is that usually it can be replaced with more readable statements (like break/continue) or by extracting a piece of code into a method. Source: James Gosling, Q&A session
This is the C ternary operator (Objective-C is a superset of C): label.frame = (inPseudoEditMode) ? kLabelIndentedRect : kLabelRect; is semantically equivalent to if(inPseudoEditMode) { label.frame = kLabelIndentedRect; } else { label.frame = kLabelRect; } The ternary with no first element (e.g. variable ?: anotherVariable) means the same as (valOrVar != 0) ? valOrVar : … Read more
In JavaScript’s if-then-else there is technically no elseif branch. But it works if you write it this way: if (condition) { } else if (other_condition) { } else { } To make it obvious what is really happening you can expand the above code using an additional pair of { and }: if (condition) { … Read more
The old syntax, with just listing the tables, and using the WHERE clause to specify the join criteria, is being deprecated in most modern databases. It’s not just for show, the old syntax has the possibility of being ambiguous when you use both INNER and OUTER joins in the same query. Let me give you … Read more
There is no for-loop, only the while-loop: DECLARE @i int = 0 WHILE @i < 20 BEGIN SET @i = @i + 1 /* do some work */ END
You probably want to use kind_of(). >> s = “something” => “something” >> s.kind_of?(Array) => false >> s = [“something”, “else”] => [“something”, “else”] >> s.kind_of?(Array) => true