java_cup
Class symbol
public abstract class symbol
extends java.lang.Object
This abstract class serves as the base class for grammar symbols (i.e.,
both terminals and non-terminals). Each symbol has a name string, and
a string giving the type of object that the symbol will be represented by
on the runtime parse stack. In addition, each symbol maintains a use count
in order to detect symbols that are declared but never used, and an index
number that indicates where it appears in parse tables (index numbers are
unique within terminals or non terminals, but not across both).
protected int | _index - Index of this symbol (terminal or non terminal) in the parse tables.
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protected String | _name - String for the human readable name of the symbol.
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protected String | _stack_type - String for the type of object used for the symbol on the parse stack.
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protected int | _use_count - Count of how many times the symbol appears in productions.
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symbol(String nm) - Constructor with default type.
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symbol(String nm, String tp) - Full constructor.
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int | index() - Index of this symbol (terminal or non terminal) in the parse tables.
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abstract boolean | is_non_term() - Indicate if this is a non-terminal.
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String | name() - String for the human readable name of the symbol.
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void | note_use() - Increment the use count.
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String | stack_type() - String for the type of object used for the symbol on the parse stack.
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String | toString() - Convert to a string.
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int | use_count() - Count of how many times the symbol appears in productions.
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_index
protected int _index
Index of this symbol (terminal or non terminal) in the parse tables.
Note: indexes are unique among terminals and unique among non terminals,
however, a terminal may have the same index as a non-terminal, etc.
_name
protected String _name
String for the human readable name of the symbol.
_stack_type
protected String _stack_type
String for the type of object used for the symbol on the parse stack.
_use_count
protected int _use_count
Count of how many times the symbol appears in productions.
symbol
public symbol(String nm)
Constructor with default type.
nm
- the name of the symbol.
symbol
public symbol(String nm,
String tp)
Full constructor.
nm
- the name of the symbol.tp
- a string with the type name.
index
public int index()
Index of this symbol (terminal or non terminal) in the parse tables.
Note: indexes are unique among terminals and unique among non terminals,
however, a terminal may have the same index as a non-terminal, etc.
is_non_term
public abstract boolean is_non_term()
Indicate if this is a non-terminal. Here in the base class we
don't know, so this is abstract.
name
public String name()
String for the human readable name of the symbol.
note_use
public void note_use()
Increment the use count.
stack_type
public String stack_type()
String for the type of object used for the symbol on the parse stack.
toString
public String toString()
Convert to a string.
use_count
public int use_count()
Count of how many times the symbol appears in productions.