9.1 Determining EOP from EOI

In many applications the EOP is always the end of input (EOI). That is, parsing ends at a known parse location. The length of the input may be known because it was fixed in advance; there may be an end of file (EOF) indication; there may be an end of string (EOS) indication; or the application may have some other means of knowing that is has hit the EOI.

If the EOI is the EOP, the following is typically the case:

• The application will treat exhaustion on failure as a parse error.
• The application will treat exhaustion before the EOI, even on success, as a parse error.

How parse exhaustion on success at the EOI is handled will depend on the application. Here are a few of the many possible ways:

• Exhaustion might be ignored. Very often this will be what the application wants to do.
• Exhaustion might be, if the application is exhaustion-loving, required, so that it is treated as an error if the parse is still active at the EOI.
• An application, if it is exhaustion-hating in the extreme, may wish to treat exhaustion, even exhaustion on success at the EOI, as an error.