Scripting Guide - SAS

368 Display Trees Chapter 11
Constructing Display Trees
Y Scale( ymin, ymax ),
Line Style( 2 ),
H Line( 0 ),
Line Style( 0 ),
Y Function( polynomial, x ),
Line Style( 3 ),
Pen Color( 3 ),
V Line( xx[1] ),
V Line( xx[2] ),
Marker Size( 2 ),
Marker( 0, {xx[1], 0}, {xx[2], 0} )
)
)
);
);
/* If no (for example, with a=3, b=4, c=5), put up an error window with a
helpful graph: */
error = Expr(
New Window( "Error",
V List Box(
Text Box( " " ),
Text Box( " Polynomial " || po || " has no real roots. " ),
Text Box( " " ),
Text Box( "Examine a graph of the function to get an idea why." ),
Graph Box(
framesize( 200, 200 ),
X Scale( -20, 20 ),
Y Scale( -20, 20 ),
Line Style( 2 ),
H Line( 0 ),
Line Style( 0 ),
Y Function( polynomial, x )
)
)
)
);
/* Either way, the script needs to have some strings ready. Rewrite the
polynomial with the coefficients specified: */
polynomial = Expr( a * x ^ 2 + b * x + c );
//Store this instance of the polynomial as a string:
po = Char( Eval Expr( polynomial ) );
//Store the solution list as a string:
xxx = Char( Eval Expr( x ) );
//Now it's ready for the test:
If( Is Missing( xx[1] ) | Is Missing( xx[2] ),
error,
results
);
When you run this script, you first see a window like this: