- Graph-structured stack
In
computer science , a graph-structured stack is adirected acyclic graph where each directed path is a stack.They are used inparsing to efficiently simulate nondeterminism forambiguous grammars .In the following diagram, there are four stacks: {7,3,1,0}, {7,4,1,0}, {7,5,2,0}, and {8,6,2,0}.:
Another way to simulate nondeterminism would be to duplicate the stack as needed. The duplication would be less efficient since vertices would not be shared. For this example, 16 vertices would be needed instead of 9.:
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