pragma class Null safety

A hint to tools.

Tools that work with Dart programs may accept hints to guide their behavior as pragma annotations on declarations. Each tool decides which hints it accepts, what they mean, and whether and how they apply to sub-parts of the annotated entity.

Tools that recognize pragma hints should pick a pragma prefix to identify the tool. They should recognize any hint with a name starting with their prefix followed by : as if it was intended for that tool. A hint with a prefix for another tool should be ignored (unless compatibility with that other tool is a goal).

A tool may recognize unprefixed names as well, if they would recognize that name with their own prefix in front.

If the hint can be parameterized, an extra options object can be added as well.

For example:

@pragma('Tool:pragma-name', [param1, param2, ...])
class Foo { }

@pragma('OtherTool:other-pragma')
void foo() { }

Here class Foo is annotated with a Tool specific pragma 'pragma-name' and function foo is annotated with a pragma 'other-pragma' specific to OtherTool.