List the criteria on the basis of which data structures used in language processing can be classified.

In language processing the data structures utilization can be classified as follow in criterion:

1. Nature of a data structure- for a non linear or linear data structure. Linear data structures contain a linear arrangement of components in memory and components require a contiguous area of memory. The components of a non-linear data structure are accessed using pointers and therefore the components need not occupy contiguous areas of memory.

2. Purpose of a data structure- for a search data structure or an allocation data structure. Search data structures are utilized during language processing to keep attribute information concerning various entities into the source program. Allocation data structures are characterized through the fact that the user of that entity identifies the address of the memory area assigned to an entity therefore no search operations are conducted upon them.

3. Lifetime of a data structure- It used during language processing or target program execution.