Assignment statements create temporary data files, in DAN's Data File
format, whose size depends on the number of steps in the processing
domain.  Such files can then be used in subsequent expressions and/or
SAVEd for latter use in other algorithms.

For example, the following assignment statement creating TMPFILE

     TMPFILE = SIN(T) / T;

causes DAN to determine the value for SIN(T), determine the value for
T, and divide the two values.  The final expression value and the
current step value are stored in a file named TMPFILE.  This process
goes on for each step value until the stop value is reached.  The
temporary file TMPFILE then contains step values and the processed data
value pairs; one for each point at which the expression is evaluated. 
This file can then be used as a term in subsequent expressions.  For
example,

      WHATSTHIS = 1.234 * X + 5.6789 * (LN(TMPFILE) * TMPFILE/2);
+
Thus an assignment statement is actually an instruction to create a
file containing multiple pairs of processed data and corresponding
independent variable values that you intend to use on the right side of
the equal sign in some other assignment statement(s), as the file
defining the X axis values for a plot, or in an expression that is the
argument to some procedure call.
