Parsing is essential for processing computer programs. A computer program must be checked to see if it is syntactically correct, and a datastructure reflecting the structure of the program built up (e.g., making clear where different statements begin/end). Then it can be compiled into a low level assembly language (or interpreted).
Parsing is also important for the interpretation of ``natural'' language such as English, and for other applications such as the processing of ``marked up'' text files (SGML). We'll include some examples of parsing natural language, as the grammar involved should be more familiar.