How does a pushdown acceptor use its storage tape to analyze a sentence?

A pushdown acceptor is a finite-state automaton that utilizes a specialized storage tape, known as a pushdown store, to analyze the syntactical structure of a sentence.1

The storage tape functions as a last-in, first-out mechanism:
* Printing and Reading: As the automaton processes an input, it can print symbols onto the store, which moves the tape to the left. Crucially, the device can only read the most recently printed symbol, followed by the next most recent, and so on.1
* Parsing: By applying specific rules, the acceptor uses this store to track and match components of a sentence. For example, it may print symbols from the input onto the store and later compare them against subsequent input symbols to verify the structure.1
* Acceptance: A sentence is considered accepted if the automaton reaches a final state while both the one-way input tape and the pushdown store are blank.1

In essence, this storage capability allows the pushdown acceptor to parse sentences within context-free languages by effectively managing the nested or reversed structures inherent in their syntax.1