Datatype properties are relations between instances of classes and RDF literals or XML schema datatypes. Concatenation of string literals and constant strings can be constant folded. String literals might be ended by newlines. Two issues with multiline string literals are leading and trailing newlines, and indentation. Typically, individual literals are 8-bits wide (ASCII), but J also supports other literals (Unicode). Structures may be initialized or assigned to using compound literals. It may be possible to modify the values of (mutable) literals in program code. Programming languages use different literals for the "null pointer". TRUE literal (and thus exactly two FALSE literals). Python has various kinds of string literals. This means that there are no statements and no variables, just operators, literals, and functions. Many languages support the use of metacharacters inside string literals. A "clause" is a disjunction of literals (or a single literal). A string of literals connected by ANDs is called a term. It also supports converting plists to Objective-C or Swift object literals.