Unlike earlier versions of TADS, there is no player command parser built into the interpreter in TADS 3. Although the built-in parser made it easy to build a game based on the standard parser, the fact that the parser was embedded in the interpreter executable made it difficult, and sometimes impossible, to customize aspects of parsing. TADS 3 eliminates the built-in parser, and instead provides an extremely powerful set of built-in support functions to simplify building a parser.
Note that in many cases, a game author will be able to ignore the lack of a built-in parser, because the standard library will provide a ready-made parser. The fact that the parser is in the library should make little difference to game authors—until they start customizing the parser, at which point having the parser in the library is a great improvement over the built-in system.
Parsing has three main components, each of which has its own chapter: