Use of these functions allows the user to specify
a default scheme for each Symbol to be
loaded.Different sources (e.g. yahoo, MySQL),
return classes (e.g. quantmod.OHLC,zoo, etc),
and more can be specified for each Symbol of
interest.
The argument list to setSymbolLookup is
simply the unquoted name of the Symbol matched
to the desired defaults.
For example, to signify that the stock data for
Sun Microsystems (SUNW) should be downloaded from
Yahoo! Finance, one would call
setSymbolLookup(SUNW='yahoo')
All changes are made to the current list, and will
persist until the end of the session. If it is
desirable to maintain the values, use saveSymbolLookup
and loadSymbolLookup.