java_cup
Class non_terminal

java.lang.Object
  java_cup.symbol
      java_cup.non_terminal

public class non_terminal
extends symbol

This class represents a non-terminal symbol in the grammar. Each non terminal has a textual name, an index, and a string which indicates the type of object it will be implemented with at runtime (i.e. the class of object that will be pushed on the parse stack to represent it).

Version:

last updated: 11/25/95

Author:

Scott Hudson

Field Summary

boolean	is_embedded_action flag non-terminals created to embed action productions
static non_terminal	START_nt special non-terminal for start symbol

Constructor Summary

non_terminal(java.lang.String nm)
Constructor with default type.

non_terminal(java.lang.String nm, java.lang.String tp)
Full constructor.

Method Summary

void	add_production(production prod) Add a production to our set of productions.
static java.util.Enumeration	all() Access to all non-terminals.
static void	compute_first_sets() Compute first sets for all non-terminals.
static void	compute_nullability() Compute nullability of all non-terminals.
static non_terminal	find(int indx) Lookup a non terminal by index.
static non_terminal	find(java.lang.String with_name) lookup a non terminal by name string
terminal_set	first_set() First set for this non-terminal.
boolean	is_non_term() Indicate that this symbol is a non-terminal.
boolean	nullable() Nullability of this non terminal.
int	num_productions() Total number of productions with this non terminal on the LHS.
static int	number() Total number of non-terminals.
java.util.Enumeration	productions() Access to productions with this non terminal on the LHS.
java.lang.String	toString() convert to string

Methods inherited from class java_cup.symbol

index, name, note_use, stack_type, use_count

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

START_nt

public static final non_terminal START_nt

special non-terminal for start symbol

is_embedded_action

public boolean is_embedded_action

flag non-terminals created to embed action productions

Constructor Detail

non_terminal

public non_terminal(java.lang.String nm,
                    java.lang.String tp)

Full constructor.

Parameters:

nm - the name of the non terminal.

tp - the type string for the non terminal.

non_terminal

public non_terminal(java.lang.String nm)

Constructor with default type.

Parameters:

nm - the name of the non terminal.

Method Detail

all

public static java.util.Enumeration all()

Access to all non-terminals.

find

public static non_terminal find(java.lang.String with_name)

lookup a non terminal by name string

find

public static non_terminal find(int indx)

Lookup a non terminal by index.

number

public static int number()

Total number of non-terminals.

compute_nullability

public static void compute_nullability()
                                throws internal_error

Compute nullability of all non-terminals.

Throws:

internal_error

compute_first_sets

public static void compute_first_sets()
                               throws internal_error

Compute first sets for all non-terminals. This assumes nullability has already computed.

Throws:

internal_error

productions

public java.util.Enumeration productions()

Access to productions with this non terminal on the LHS.

num_productions

public int num_productions()

Total number of productions with this non terminal on the LHS.

add_production

public void add_production(production prod)
                    throws internal_error

Add a production to our set of productions.

Throws:

internal_error

nullable

public boolean nullable()

Nullability of this non terminal.

first_set

public terminal_set first_set()

First set for this non-terminal.

is_non_term

public boolean is_non_term()

Indicate that this symbol is a non-terminal.

Specified by:

is_non_term in class symbol

toString

public java.lang.String toString()

convert to string

Overrides:

toString in class symbol