From 0f1055b8d7f97d86c66fa602c17666bc2ff9c437 Mon Sep 17 00:00:00 2001 From: Constantin Jucovschi Date: Tue, 31 Mar 2009 06:18:54 -0400 Subject: Initial commit --- src/syntaxParser/java_cup/symbol.java | 107 ++++++++++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 src/syntaxParser/java_cup/symbol.java (limited to 'src/syntaxParser/java_cup/symbol.java') diff --git a/src/syntaxParser/java_cup/symbol.java b/src/syntaxParser/java_cup/symbol.java new file mode 100644 index 0000000..94d8b7d --- /dev/null +++ b/src/syntaxParser/java_cup/symbol.java @@ -0,0 +1,107 @@ +package java_cup; + +/** 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). + * + * @see java_cup.terminal + * @see java_cup.non_terminal + * @version last updated: 7/3/96 + * @author Frank Flannery + */ +public abstract class symbol { + /*-----------------------------------------------------------*/ + /*--- Constructor(s) ----------------------------------------*/ + /*-----------------------------------------------------------*/ + + /** Full constructor. + * @param nm the name of the symbol. + * @param tp a string with the type name. + */ + public symbol(String nm, String tp) + { + /* sanity check */ + if (nm == null) nm = ""; + + /* apply default if no type given */ + if (tp == null) tp = "Object"; + + _name = nm; + _stack_type = tp; + } + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** Constructor with default type. + * @param nm the name of the symbol. + */ + public symbol(String nm) + { + this(nm, null); + } + + /*-----------------------------------------------------------*/ + /*--- (Access to) Instance Variables ------------------------*/ + /*-----------------------------------------------------------*/ + + /** String for the human readable name of the symbol. */ + protected String _name; + + /** String for the human readable name of the symbol. */ + public String name() {return _name;} + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** String for the type of object used for the symbol on the parse stack. */ + protected String _stack_type; + + /** String for the type of object used for the symbol on the parse stack. */ + public String stack_type() {return _stack_type;} + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** Count of how many times the symbol appears in productions. */ + protected int _use_count = 0; + + /** Count of how many times the symbol appears in productions. */ + public int use_count() {return _use_count;} + + /** Increment the use count. */ + public void note_use() {_use_count++;} + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** 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. + */ + 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. + */ + public int index() {return _index;} + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** Indicate if this is a non-terminal. Here in the base class we + * don't know, so this is abstract. + */ + public abstract boolean is_non_term(); + + /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ + + /** Convert to a string. */ + public String toString() + { + return name(); + } + + /*-----------------------------------------------------------*/ + +} -- cgit