LocalStaticScope.java

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 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
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 *
 * Software distributed under the License is distributed on an "AS
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 * Copyright (C) 2006 Thomas E Enebo <enebo@acm.org>
 * 
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package org.jruby.parser;

import org.jruby.ast.AssignableNode;
import org.jruby.ast.LocalAsgnNode;
import org.jruby.ast.LocalVarNode;
import org.jruby.ast.Node;
import org.jruby.ast.VCallNode;
import org.jruby.lexer.yacc.ISourcePosition;

public class LocalStaticScope extends StaticScope {
    private static final long serialVersionUID = 2204064248888411628L;

    public LocalStaticScope(StaticScope enclosingScope) {
        super(enclosingScope);
        
        addVariable("$~");
        addVariable("$_");
    }

    public StaticScope getLocalScope() {
        return this;
    }

    public int isDefined(String name, int depth) {
        return (depth << 16) | exists(name);
    }

    /**
     * @see org.jruby.parser.StaticScope#getAllNamesInScope()
     */
    public String[] getAllNamesInScope() {
        String[] variables = getVariables();

        // We subtract two since we know $_ and $~ are there and they are special and not
        // what Ruby considers a local name.  BTW- We always add $~ and $_ so we know variables
        // cannot be null.
        int localNamesSize = variables.length - 2;
        
        String[] names = new String[localNamesSize];
        System.arraycopy(variables, 2, names, 0, localNamesSize);
        
        return names;
    }
    
    public AssignableNode assign(ISourcePosition position, String name, Node value, 
            StaticScope topScope, int depth) {
        int slot = exists(name);
        
        // We can assign if we already have variable of that name here or we are the only
        // scope in the chain (which Local scopes always are).
        if (slot >= 0) {
            //System.out.println("LASGN1: " + name + ", l: " + depth + ", i: " + slot);

            return new LocalAsgnNode(position, name, ((depth << 16) | slot), value);
        } else if (topScope == this) {
            slot = addVariable(name);
            //System.out.println("LASGN2: " + name + ", l: " + depth + ", i: " + slot);

            return new LocalAsgnNode(position, name, slot , value);
        }
        
        // We know this is a block scope because a local scope cannot be within a local scope
        // If topScope was itself it would have created a LocalAsgnNode above.
        return ((BlockStaticScope) topScope).addAssign(position, name, value);
    }

    public Node declare(ISourcePosition position, String name, int depth) {
        int slot = exists(name);
        
        if (slot >= 0) {
            //System.out.println("LVAR: " + name + ", l: " + depth + ", i: " + slot);
            return new LocalVarNode(position, ((depth << 16) | slot), name);
        }
        
        return new VCallNode(position, name);
    }

}