. Make local correction to the input
. Works only in limited situations
- A common programming error which is easily detected
- For example insert a ";" after closing "}" of a class definition
. Does not work very well!
Phrase level recovery is implemented by filling in the blank entries in the predictive parsing table with pointers to error routines. These routines may change, insert, or delete symbols on the input and issue appropriate error messages. They may also pop from the stack. It basically makes local corrections to the input; that is, it may replace a prefix of the remaining input by some string that allows the parser to continue. A typical local correction would be to replace a comma by a semicolon, delete an extraneous semicolon, or insert a missing semicolon. This type of replacement can correct any input string and has been used in several error-repairing compilers. However, its major drawback is the difficulty it has in coping with situations in which the actual error has occurred before the point of detection.
