1. A computer-implemented method for facilitating the evaluation of an equation that is used during circuit design or validation by a software program, comprising: obtaining one or more data-access functions to be used in the equation, wherein the one or more data-access functions access data from one or more data sources based on an analysis context; obtaining the analysis context for the equation separately from the data-access functions, wherein the analysis context includes at least one of: information of whether the data that is to be used to evaluate the equation is in time domain or frequency domain, an analysis time window to select the data that is to be used to evaluate the equation, or an analysis frequency range to select the data that is to be used to evaluate the equation; and using a computer to evaluate the equation by using the data-access functions.