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/*******************************************************************************
* Copyright (c) 2010 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
package org.luaj.vm2.ast;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
public class NameScope {
private static final Set<String> LUA_KEYWORDS = new HashSet<String>();
static {
String[] k = new String[] {
"and", "break", "do", "else", "elseif", "end",
"false", "for", "function", "if", "in", "local",
"nil", "not", "or", "repeat", "return",
"then", "true", "until", "while" };
for ( int i=0; i<k.length; i++ )
LUA_KEYWORDS.add( k[i] );
}
public final Map<String,Variable> namedVariables = new HashMap<String,Variable>();
public final NameScope outerScope;
public int functionNestingCount;
/** Construct default names scope */
public NameScope() {
this.outerScope = null;
this.functionNestingCount = 0;
}
/** Construct name scope within another scope*/
public NameScope(NameScope outerScope) {
this.outerScope = outerScope;
this.functionNestingCount = outerScope!=null? outerScope.functionNestingCount: 0;
}
/** Look up a name. If it is a global name, then throw IllegalArgumentException. */
public Variable find( String name ) throws IllegalArgumentException {
validateIsNotKeyword(name);
for ( NameScope n = this; n!=null; n=n.outerScope )
if ( n.namedVariables.containsKey(name) )
return (Variable)n.namedVariables.get(name);
Variable value = new Variable(name);
this.namedVariables.put(name, value);
return value;
}
/** Define a name in this scope. If it is a global name, then throw IllegalArgumentException. */
public Variable define( String name ) throws IllegalStateException, IllegalArgumentException {
validateIsNotKeyword(name);
Variable value = new Variable(name, this);
this.namedVariables.put(name, value);
return value;
}
private void validateIsNotKeyword(String name) {
if ( LUA_KEYWORDS.contains(name) )
throw new IllegalArgumentException("name is a keyword: '"+name+"'");
}
}