DScriptExecutor.java

/* --------------------------------------------------------- *
 *    __________    D E L T A S C R I P T                    *
 *   (_________()                                            *
 *    /  ===   /   - A fast, dynamic scripting language      *
 *   |  ==    |    - Version 4.13.11.0                       *
 *   /  ===   /    - Developed by Adam R. Nelson             *
 *  |  =  =  |     - 2011-2013                               *
 *  /  ===   /     - Distributed under GNU LGPL v3           *
 * (________()     - http://github.com/ar-nelson/deltascript *
 *                                                           *
 * --------------------------------------------------------- */

package com.sector91.delta.script;

import com.sector91.delta.script.instrs.DSInstr;
import com.sector91.delta.script.objects.DS_Array;
import com.sector91.delta.script.objects.DS_Callable;
import com.sector91.delta.script.objects.DS_Object;
import com.sector91.delta.script.objects.DS_Scope;
import com.sector91.delta.script.objects.DS_String;

public class DScriptExecutor
{
    private final DSInstr instr;
    private final DS_Scope scope;
    private final DScriptContext context;

    public boolean functionCall, loopBreak, loopContinue, returnBreak;
    
    DScriptExecutor(DSInstr instr, DS_Scope scope, boolean functionCall,
            DScriptContext context)
    {
        this.instr = instr;
        this.scope = scope;
        this.functionCall = functionCall;
        this.context = context==null ? new DScriptContext() : context;
    }
    
    public DScriptContext getContext()
    {return context;}
    
    DS_Object execInstance() throws DScriptErr
    {
        DScriptContext.push(context);        
        try
        {return instr.exec(scope, this);}
        catch (DScriptErr ex)
        {return tryToHandleError(scope, instr, ex);}
        finally
        {DScriptContext.pop();}
    }
    
    DS_Object execInstrAsFunctionCall(DSInstr instr, DS_Scope scope)
        throws DScriptErr
    {
        DScriptContext.push(context);
        try
        {
            if (functionCall) return instr.exec(scope, this);
            else
            {
                functionCall = true;
                final DS_Object retval = instr.exec(scope, this);
                functionCall = false;
                return retval;
            }
        }
        catch (Exception ex)
        {return tryToHandleError(scope, instr, ex);}
        finally
        {DScriptContext.pop();}
    }
    
    public DS_Object tryToHandleError(DS_Scope scope, DSInstr instr,
        Exception ex) throws DScriptErr
    {
        final DScriptErr dex;
        if (ex instanceof DScriptErr)
            dex = (DScriptErr)ex;
        else
            dex = new DScriptErr(ex.getMessage(), ex, instr);
        DS_Scope cs   = scope;
        DS_Object err = scope.getLocal(DeltaScript.ERROR_FUNC_NAME);
        while (!cs.isRootScope() &&
               (err == null || !(err instanceof DS_Callable) || scope.is(err)))
        {
            cs = cs.getParent();
            err = cs.getLocal(DeltaScript.ERROR_FUNC_NAME);
        }
        if (cs.isRootScope())
            throw dex;
        else
            return ((DS_Callable)err).call(
                new DS_String(dex.getMessage()),
                new DS_Array(dex.tags.toArray(new DS_Object[dex.tags.size()])),
                new DS_Array(dex.getInstrStackTrace()));
    }
}