unix/ValueFunction.cpp

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/******************************************************************************/
/* REXX Unit Support                                                          */
/*                                                                            */
/* Unix system specific VALUE() built-in function routine                     */
/*                                                                            */
/******************************************************************************/
 
#include "RexxCore.h"
#include "StringClass.hpp"
#include "ActivityManager.hpp"
#include "SystemInterpreter.hpp"
 
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
 
#define  SELECTOR  "ENVIRONMENT"       /* environment selector              */
 
 
/**
 * Process a value function call for external repositories.
 *
 * @param Name     The variable name.
 * @param NewValue The new value to assign to that variable.
 * @param Selector The variable pool selector.
 * @param result   The returned existing value.
 *
 * @return true if this worked, false otherwise.
 */
bool SystemInterpreter::valueFunction(RexxString *name, RexxObject *newValue, RexxString *selector, RexxObject *&result)
{
    // we only recognize the environemnt selector
    if (!selector->strCaselessCompare(SELECTOR))
    {
        return false;                    // we can't handle this one
    }
 
    // if not there, we return a null string
    result = OREF_NULLSTRING;
 
    // see if we have an existing variable first
    const char *oldValue = getenv(name->getStringData());
    // either return the existing variable value or a null string.
    if (oldValue != NULL)
    {
        result = new_string(oldValue);
    }
 
    // set the variable if we have a new value
    if (newValue != OREF_NULL)
    {
        // .nil is special, it removes the variable
        if (newValue == (RexxString *)TheNilObject)
        {
            unsetenv(name->getStringData());
        }
        // we need a string value for the set.
        else
        {
            setenv(name->getStringData(), stringArgument(newValue, OREF_positional, ARG_TWO)->getStringData(), true) ;
        }
    }
    return true;
}