PointAnswers1
Answer is a Point or a List of Points
This PG code shows how to evaluate answers that are points or lists of points.
 File location in OPL: FortLewis/Authoring/Templates/Precalc/PointAnswers1.pg
 PGML location in OPL: FortLewis/Authoring/Templates/Precalc/PointAnswers1_PGML.pg
PG problem file  Explanation 

Problem tagging: 

DOCUMENT(); loadMacros( "PGstandard.pl", "MathObjects.pl", "AnswerFormatHelp.pl", "contextLimitedPoint.pl", ); TEXT(beginproblem()); 
Initialization:
We only need to load 
Context("LimitedPoint"); $f = Compute("x^21"); $xint = List( Point("(1,0)"), Point("(1,0)") ); $yint = List( Point("(0,1)") ); 
Setup:
We could have used 
Context()>texStrings; BEGIN_TEXT Enter the xintercept(s) and yintercept(s) of \( y = $f \). Enter a point as \( (a,b) \), including the parentheses. If there is more than one correct answer, enter a comma separated list of points. $BR $BR xintercept(s): \{ ans_rule(20) \} \{ AnswerFormatHelp("points") \} $BR yintercept(s): \{ ans_rule(20) \} \{ AnswerFormatHelp("points") \} END_TEXT Context()>normalStrings; 
Main Text: Be sure to tell students the proper syntax for how to enter their answers. 
$showPartialCorrectAnswers = 1; ANS( $xint>cmp() ); ANS( $yint>cmp() ); 
Answer Evaluation: 
Context()>texStrings; BEGIN_SOLUTION ${PAR}SOLUTION:${PAR} Solution explanation goes here. END_SOLUTION Context()>normalStrings; COMMENT('MathObject version.'); ENDDOCUMENT(); 
Solution: 