Package java_cup
Class symbol
java.lang.Object
java_cup.symbol
- Direct Known Subclasses:
non_terminal
,terminal
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).
- Version:
- last updated: 7/3/96
- Author:
- Frank Flannery
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected int
Index of this symbol (terminal or non terminal) in the parse tables.protected String
String for the human readable name of the symbol.protected String
String for the type of object used for the symbol on the parse stack.protected int
Count of how many times the symbol appears in productions. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
index()
Index of this symbol (terminal or non terminal) in the parse tables.abstract boolean
Indicate if this is a non-terminal.name()
String for the human readable name of the symbol.void
note_use()
Increment the use count.String for the type of object used for the symbol on the parse stack.toString()
Convert to a string.int
Count of how many times the symbol appears in productions.
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Field Details
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_name
String for the human readable name of the symbol. -
_stack_type
String for the type of object used for the symbol on the parse stack. -
_use_count
protected int _use_countCount of how many times the symbol appears in productions. -
_index
protected int _indexIndex 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.
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Constructor Details
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symbol
Full constructor.- Parameters:
nm
- the name of the symbol.tp
- a string with the type name.
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symbol
Constructor with default type.- Parameters:
nm
- the name of the symbol.
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Method Details
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name
String for the human readable name of the symbol. -
stack_type
String for the type of object used for the symbol on the parse stack. -
use_count
public int use_count()Count of how many times the symbol appears in productions. -
note_use
public void note_use()Increment the use count. -
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. -
toString
Convert to a string.
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