Type Parameters:

V - the type of the value objects

All Superinterfaces:

Iterable<V>

All Known Implementing Classes:

DebuggingValueStack, DefaultValueStack
```
public interface ValueStack<V>
extends Iterable<V>
```
A ValueStack is a stack implementation for parser values. The current state of the stack can be saved and restored with the methods takeSnapshot() and restoreSnapshot(Object) ()}, whose implementations should be super efficient since they are being used extensively during a parsing run. A ValueStack also serves as an Iterable over the current stack values (the values are being provided with the last value (on top of the stack) first).

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`clear()`	Clears all values.
`void`	`dup()`	Duplicates the top value.
`boolean`	`isEmpty()`	Determines whether the stack is empty.
`V`	`peek()`	Returns the value at the top of the stack without removing it.
`V`	`peek(int down)`	Returns the value the given number of elements below the top of the stack without removing it.
`void`	`poke(int down, V value)`	Replaces the element the given number of elements below the current top of the stack.
`void`	`poke(V value)`	Replaces the current top value with the given value.
`V`	`pop()`	Removes the value at the top of the stack and returns it.
`V`	`pop(int down)`	Removes the value the given number of elements below the top of the stack.
`void`	`push(int down, V value)`	Inserts the given value a given number of elements below the current top of the stack.
`void`	`push(V value)`	Pushes the given value onto the stack.
`void`	`pushAll(Iterable<V> values)`	Pushes all given elements onto the stack (in the order as given).
`void`	`pushAll(V firstValue, V... moreValues)`	Pushes all given elements onto the stack (in the order as given).
`void`	`restoreSnapshot(Object snapshot)`	Restores the stack state as previously returned by `takeSnapshot()`.
`int`	`size()`	Returns the number of elements currently on the stack.
`void`	`swap()`	Swaps the top two stack values.
`void`	`swap3()`	Reverses the order of the top 3 stack values.
`void`	`swap4()`	Reverses the order of the top 4 stack values.
`void`	`swap5()`	Reverses the order of the top 5 stack values.
`void`	`swap6()`	Reverses the order of the top 5 stack values.
`Object`	`takeSnapshot()`	Returns an object representing the current state of the stack.

Methods inherited from interface java.lang.Iterable
forEach, iterator, spliterator

- Method Detail
  - isEmpty
```
boolean isEmpty()
```
    Determines whether the stack is empty.
    
    Returns:
    
    true if empty
  - size
```
int size()
```
    Returns the number of elements currently on the stack.
    
    Returns:
    
    the number of elements
  - clear
```
void clear()
```
    Clears all values.
  - takeSnapshot
```
Object takeSnapshot()
```
    Returns an object representing the current state of the stack. This cost of running this operation is negligible and independent from the size of the stack.
    
    Returns:
    
    an object representing the current state of the stack
  - restoreSnapshot
```
void restoreSnapshot(Object snapshot)
```
    Restores the stack state as previously returned by takeSnapshot(). This cost of running this operation is negligible and independent from the size of the stack.
    
    Parameters:
    
    snapshot - a snapshot object previously returned by takeSnapshot()
  - push
```
void push(V value)
```
    Pushes the given value onto the stack. Equivalent to push(0, value).
    
    Parameters:
    
    value - the value
  - push
```
void push(int down,
          V value)
```
    Inserts the given value a given number of elements below the current top of the stack.
    
    Parameters:
    
    down - the number of elements to skip before inserting the value (0 being equivalent to push(value))
    
    value - the value
    
    Throws:
    
    IllegalArgumentException - if the stack does not contain enough elements to perform this operation
  - pushAll
```
void pushAll(V firstValue,
             V... moreValues)
```
    Pushes all given elements onto the stack (in the order as given).
    
    Parameters:
    
    firstValue - the first value
    
    moreValues - the other values
  - pushAll
```
void pushAll(Iterable<V> values)
```
    Pushes all given elements onto the stack (in the order as given).
    
    Parameters:
    
    values - the values
  - pop
```
V pop()
```
    Removes the value at the top of the stack and returns it.
    
    Returns:
    
    the current top value
    
    Throws:
    
    IllegalArgumentException - if the stack is empty
  - pop
```
V pop(int down)
```
    Removes the value the given number of elements below the top of the stack.
    
    Parameters:
    
    down - the number of elements to skip before removing the value (0 being equivalent to pop())
    
    Returns:
    
    the value
    
    Throws:
    
    IllegalArgumentException - if the stack does not contain enough elements to perform this operation
  - peek
```
V peek()
```
    Returns the value at the top of the stack without removing it.
    
    Returns:
    
    the current top value
    
    Throws:
    
    IllegalArgumentException - if the stack is empty
  - peek
```
V peek(int down)
```
    Returns the value the given number of elements below the top of the stack without removing it.
    
    Parameters:
    
    down - the number of elements to skip (0 being equivalent to peek())
    
    Returns:
    
    the value
    
    Throws:
    
    IllegalArgumentException - if the stack does not contain enough elements to perform this operation
  - poke
```
void poke(V value)
```
    Replaces the current top value with the given value. Equivalent to poke(0, value).
    
    Parameters:
    
    value - the value
    
    Throws:
    
    IllegalArgumentException - if the stack is empty
  - poke
```
void poke(int down,
          V value)
```
    Replaces the element the given number of elements below the current top of the stack.
    
    Parameters:
    
    down - the number of elements to skip before replacing the value (0 being equivalent to poke(value))
    
    value - the value to replace with
    
    Throws:
    
    IllegalArgumentException - if the stack does not contain enough elements to perform this operation
  - dup
```
void dup()
```
    Duplicates the top value. Equivalent to push(peek()).
    
    Throws:
    
    IllegalArgumentException - if the stack is empty
  - swap
```
void swap()
```
    Swaps the top two stack values.
    
    Throws:
    
    GrammarException - if the stack does not contain at least two elements
  - swap3
```
void swap3()
```
    Reverses the order of the top 3 stack values.
    
    Throws:
    
    GrammarException - if the stack does not contain at least 3 elements
  - swap4
```
void swap4()
```
    Reverses the order of the top 4 stack values.
    
    Throws:
    
    GrammarException - if the stack does not contain at least 4 elements
  - swap5
```
void swap5()
```
    Reverses the order of the top 5 stack values.
    
    Throws:
    
    GrammarException - if the stack does not contain at least 5 elements
  - swap6
```
void swap6()
```
    Reverses the order of the top 5 stack values.
    
    Throws:
    
    GrammarException - if the stack does not contain at least 5 elements

Interface ValueStack<V>

Method Summary

Methods inherited from interface java.lang.Iterable

Method Detail

isEmpty

size

clear

takeSnapshot

restoreSnapshot

push

push

pushAll

pushAll

pop

pop

peek

peek

poke

poke

dup

swap

swap3

swap4

swap5

swap6