An expression or spread chart is constructed using one or more contracts, numerical constants and simple mathematical operators (+-*/). All Expression or spreads must begin with an equal sign (=).
All Special Symbols (Preferreds, Warrants, Units, etc), Futures, Index or Options Symbols must be enclosed with a single quotation marks ( ' ) at the beginning and the end of the symbol. Example: 'CL H2', 'JPM/PB', 'BAC/WA', '$INDU'
Expressions are calculated from left to right using Standard Mathematical order. Use parentheses to change the order of the calculations, numerical constant and mathematical operator.
here are some example:
='$spx' - 'sp m2'
=’rim-tc’ – rimm
=((ibm-msft) / '$indu'))
=’bac/pc’ – bac
contracts used in an expression can be the explicit contract ('sp h2', 'us m2005', etc.), a nearby contract ('sp 1!', 'us 1!', etc.) or a forward contract ('sp 3!', 'us 3!', etc.).
=(('cl h2'+'clj2'+'cl k2')/3)
=(‘cl 1!’ + ‘cl 2!’ + ‘cl 3!’) /3
=('xrb 1!' * 28 +'ho 1!' * 14) - 'cl 1!'
when using expressions in a watchlist or chart, you can specify the price field that is used (if omitted, last is default). this is done by using the dot (.) operator.
=msft.low / csco.low
=goog.low / 'rim-tc'.high
chartable expressions do not display the open, high, low, close, and change fields in the chart's header, they simply display the result of the expression.
Certain studies are also unavailable on expression charts