text() and node() are node tests, in XPath terminology (compare). Node tests operate on a set (on an axis, to be exact) of nodes and return the ones that are of a certain type. When no axis is mentioned, the child axis is assumed by default. There are all kinds of node tests: node() matches … Read more
In C++, for user-defined types a + b is a function call, and the standard says: §5.2.2.8 – […] The order of evaluation of function arguments is unspecified. […] For normal operators, the standard says: §5.4 – Except where noted, the order of evaluation of operands of individual operators and subexpressions of individual expressions, and … Read more
After 5 years, the cmdlet I had pasted in the original answer has undergone so many updates that it has become completely outdated. Therefore I have replaced the code and the ReadMe with a link to the latest version. Besides the support for more object types and better formatting, it now outputs an expression (ScriptBlock), … Read more
The assignment operator in Java evaluates to the assigned value (like it does in, e.g., c). So here, readLine() will be executed, and its return value stored in line. That stored value is then checked against null, and if it’s null then the loop will terminate.
Extending @KooiInc answer, you can avoid manually escaping every special character by using the source property of the RegExp object. Example: var urlRegex= new RegExp(” + /(?:(?:(https?|ftp):)?\/\/)/.source // protocol + /(?:([^:\n\r]+):([^@\n\r]+)@)?/.source // user:pass + /(?:(?:www\.)?([^\/\n\r]+))/.source // domain + /(\/[^?\n\r]+)?/.source // request + /(\?[^#\n\r]*)?/.source // query + /(#?[^\n\r]*)?/.source // anchor ); or if you want to … Read more
The assignment expression operator := added in Python 3.8 supports assignment inside of lambda expressions. This operator can only appear within a parenthesized (…), bracketed […], or braced {…} expression for syntactic reasons. For example, we will be able to write the following: import sys say_hello = lambda: ( message := “Hello world”, sys.stdout.write(message + … Read more
The non-greedy regex modifiers are like their greedy counter-parts but with a ? immediately following them: * – zero or more *? – zero or more (non-greedy) + – one or more +? – one or more (non-greedy) ? – zero or one ?? – zero or one (non-greedy)
Further to Thomas’s answer, it’s actually possible to access the (deprecated) JScript libraries directly from C#, which means you can use the equivalent of JScript’s eval function. using Microsoft.JScript; // needs a reference to Microsoft.JScript.dll using Microsoft.JScript.Vsa; // needs a reference to Microsoft.Vsa.dll // … string expr = “7 + (5 * 4)”; Console.WriteLine(JScriptEval(expr)); // … Read more
Section 6.6/3, “Constant expressions”, of the ISO C99 standard is the section you need. It states: Constant expressions shall not contain assignment, increment, decrement, function-call, or comma operators, except when they are contained within a subexpression that is not evaluated. In the C99 rationale document from ISO, there’s this little snippet: An integer constant expression … Read more
Ooh, it’s not easy at all. Func<T> represents a generic delegate and not an expression. If there’s any way you could do so (due to optimizations and other things done by the compiler, some data might be thrown away, so it might be impossible to get the original expression back), it’d be disassembling the IL … Read more