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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* Copyright (C) 1998-2001 Gerwin Klein <lsf@jflex.de> *
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* All rights reserved. *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License. See the file *
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* COPYRIGHT for more information. *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* You should have received a copy of the GNU General Public License along *
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* with this program; if not, write to the Free Software Foundation, Inc., *
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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* Symbol table and expander for macros.
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* Maps macros to their (expanded) definitions, detects cycles and
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* @author Gerwin Klein
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* @version JFlex 1.3.5, $Revision: 1.14 $, $Date: 2001/10/08 10:08:02 $
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final public class Macros {
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* Maps names of macros to their definition
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private Hashtable macros;
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private Hashtable used;
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* Creates a new macro expander.
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macros = new Hashtable();
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used = new Hashtable();
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* Stores a new macro and its definition.
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* @param name the name of the new macro
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* @param definition the definition of the new macro
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* @return <code>true</code>, iff the macro name has not been
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public boolean insert(String name, RegExp definition) {
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Out.debug("inserting macro "+name+" with definition :"+Out.NL+definition);
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used.put(name, new Boolean(false));
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return macros.put(name,definition) == null;
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* Marks a makro as used.
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* @return <code>true</code>, iff the macro name has been
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public boolean markUsed(String name) {
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return used.put(name, new Boolean(true)) != null;
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* Tests if a macro has been used.
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* @return <code>true</code>, iff the macro has been used in
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* a regular expression.
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public boolean isUsed(String name) {
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return ((Boolean)used.get(name)).booleanValue();
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* Returns all unused macros.
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* @return the enumeration of macro-names that have not been used.
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public Enumeration unused() {
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Vector unUsed = new Vector();
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Enumeration names = used.keys();
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while ( names.hasMoreElements() ) {
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String name = (String) names.nextElement();
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Boolean isUsed = (Boolean) used.get( name );
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if ( !isUsed.booleanValue() ) unUsed.addElement(name);
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return unUsed.elements();
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* Fetches the definition of the macro with the specified name,
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* The definition will either be the same as stored (expand() not
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* called), or an equivalent one, that doesn't contain any macro
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* usages (expand() called before).
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* @param name the name of the macro
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* @return the definition of the macro, <code>null</code> if
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* no macro with the specified name has been stored.
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* @see JFlex.Macros#expand
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public RegExp getDefinition(String name) {
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return (RegExp) macros.get(name);
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* Expands all stored macros, so that getDefinition always returns
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* a defintion that doesn't contain any macro usages.
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* @throws MacroException if there is a cycle in the macro usage graph.
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public void expand() throws MacroException {
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names = macros.keys();
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while ( names.hasMoreElements() ) {
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String name = (String) names.nextElement();
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macros.put(name, expandMacro(name, getDefinition(name)));
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// this put doesn't get a new key, so only the a new value
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// is set for the key "name" (without changing the enumeration
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* Expands the specified macro by replacing each macro usage
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* with the stored definition.
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* @param name the name of the macro to expand (for detecting cycles)
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* @param definition the definition of the macro to expand
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* @return the expanded definition of the macro.
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* @throws MacroException when an error (such as a cyclic definition)
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* occurs during expansion
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private RegExp expandMacro(String name, RegExp definition) throws MacroException {
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// Out.print("checking macro "+name);
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// Out.print("definition is "+definition);
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switch ( definition.type ) {
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RegExp2 binary = (RegExp2) definition;
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binary.r1 = expandMacro(name, binary.r1);
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binary.r2 = expandMacro(name, binary.r2);
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RegExp1 unary = (RegExp1) definition;
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unary.content = expandMacro(name, (RegExp) unary.content);
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String usename = (String) ((RegExp1) definition).content;
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if ( name.equals(usename) )
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throw new MacroException("Macro "+name+" contains a cycle");
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RegExp usedef = getDefinition(usename);
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if ( usedef == null )
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throw new MacroException("Found no definition for {"+usename+"} while expanding {"+name+"}");
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return expandMacro(name, usedef);
added
removed
src/JFlex/Macros.java
