Markup sink data type

A markup sink consumes a markup stream; that is, a stream of data content that includes markup events. markup sink is a subtype of string sink ; therefore, a markup sink can be used anywhere a string sink could be used.

Generally speaking, all actions and operators that work with string sink will also work with markup sink. There are a few things to keep in mind, however:

• A put action that has a markup sink as its left hand argument can have either a markup sink or a string sink as its right hand argument. If the left hand argument is a string sink , though, then the right hand argument must also be a string sink .
• The output-to action accepts a markup sink as well as a string sink with the same restrictions on scope-escaping.
• The actions close , discard , and flush behave the same way on a markup sink as they would on a string sink . None of these actions works on a value argument.
• The fork operator (& ) can be used with markup sink arguments. If both arguments have markup sink type, then the result is also a markup sink. If one argument is a string sink , then the result is also a string sink .
• The deprecated form of & , and , will accept markup sink arguments because they are a subtype of string sink . However, the result is always a string sink .
• Any user-defined function that takes a string sink argument will also accept a markup sink in that position.
• There is a built-in markup sink cast operator that tries to invoke an appropriate user-defined conversion function.