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backport (dpvc): Fixed an error with the custom list checker setting the wrong field for the checker (OOPS!)
1 loadMacros('Parser.pl'); 2 3 sub _answerCustom_init {}; # don't reload this file 4 5 ###################################################################### 6 # 7 # This answer checker provides an easy method for creating an answer 8 # checker with a custom subroutine that performs the check for 9 # correctness. 10 # 11 # Pass the correct answer (either as a string or as a Parser object) 12 # as the first argument, and a reference to the checker subroutine 13 # as the second argument. Additional parameters can follow. These 14 # include any of the parameters for the usual answer checker of the 15 # of the type of the correct answer (e.g., showCoordinateHints), plus 16 # the following: 17 # 18 # sameClass => 0 or 1 If 1 (the default), only call the 19 # custom checker if the student answer 20 # is the same object class as the correct 21 # answer (e.g., both are points). 22 # If 0, the checker will be called 23 # whenever the student answer passes 24 # the typeMatch check for the correct 25 # answer. For example, if the correct 26 # answer is a vector, and promotePoints 27 # has been set to 1, then the checker 28 # will be called when the student answer 29 # is a vector OR a point. 30 # 31 # sameLength => 0 or 1 If 1 (the default), only call the 32 # custom checker if the student answer 33 # has the same number of coordinates as 34 # the correct answer. 35 # 36 # If the correct answer is a list, the custom checker will be called 37 # on the individual entries of the list, not on the list as a whole. 38 # If the list is an unordered list, the routine may be called 39 # multiple times with various combinations of student and professor's 40 # answers in order to find a correct match. 41 # 42 # The checker routine will be passed the correct answer, the 43 # student's answer, and the answer evaluator object, in that order. 44 # 45 # For example, the following checks if a student entered 46 # a unit vector (any unit vector in R^3 will do): 47 # 48 # custom_cmp("<1,2,3>",sub { 49 # my ($correct,$student,$ans) = @_; 50 # return norm($student) == 1; 51 # }); 52 # 53 # The checker subroutine can call Value::Error(message) to generate 54 # an error message that will be reported in the table at the top of 55 # the page. If the checker generates a fatal runtime error (e.g., 56 # calls the "die" function), then the message is reported with the 57 # "pink screen of death", and includes a request for the student to 58 # inform the instructor. 59 # 60 61 sub custom_cmp { 62 my $correct = shift; my $checker = shift; 63 die "custom_cmp requires a correct answer" unless defined($correct); 64 die "custom_cmp requires a checker subroutine" unless defined($checker); 65 $correct = Value::makeValue($correct); 66 $correct = main::Formula($correct) unless Value::isValue($correct); 67 $correct->cmp( 68 checker => sub { 69 my ($correct,$student,$ans) = @_; 70 return 0 if $ans->{sameClass} && $correct->class ne $student->class; 71 return 0 if $ans->{sameLength} && $correct->length != $student->length; 72 return &{$ans->{custom_checker}}($correct,$student,$ans); 73 }, 74 custom_checker => $checker, 75 sameClass => 1, 76 sameLength => 1, 77 showEqualErrors => 1, # make sure we see errors in list checker 78 @custom_cmp_defaults, 79 @_, 80 ); 81 } 82 83 # 84 # Set this to include any default parameters you want 85 # to include in the custom answer checkers 86 # 87 @custom_cmp_defaults = (); 88 89 90 # 91 # This one installs a custom list-based answer checker (for the 92 # List and Union classes). Basically it is just a shell that makes 93 # it a little easier to do, and provides an interface similar to 94 # custom_cmp. 95 # 96 # You pass the correct answer (as a string or as a List or Union 97 # object) as the first argument, and the custom list checker as 98 # the second argument. You can pass any additional parameters 99 # that should be included in the answer checker following those 100 # two required ones. 101 # 102 # The checker will be passed a reference to the array of correct 103 # answers, a reference to the array of student answers, and 104 # the answer evaluator object. Note that the correct and student 105 # answers are array references, not List structures (this is because 106 # a list of formulas becomes a formula returning a list, so in order 107 # to keep the formulas separate, they are passed in an array). 108 # 109 # For example, the following checks for any list of the same length 110 # as the instructor's list. (A stupid checker, but just an example.) 111 # 112 # custom_list_cmp("1,2,3",sub { 113 # my ($correct,$student,$ans) = @_; 114 # scalar(@{$correct}) == scalar(@{$student}); 115 # }); 116 # 117 # The checker subroutine can call Value::Error(message) to generate 118 # an error message that will be reported in the table at the top of 119 # the page. If the checker generates a fatal runtime error (e.g., 120 # calls the "die" function), then the message is reported with the 121 # "pink screen of death", and includes a request for the student to 122 # inform the instructor. 123 # 124 125 sub custom_list_cmp { 126 my $correct = shift; my $checker = shift; 127 die "custom_list_cmp requires a correct answer" unless defined($correct); 128 die "custom_list_cmp requires a checker subroutine" unless defined($checker); 129 $correct = Value::makeValue($correct); 130 $correct = main::Formula($correct) unless Value::isValue($correct); 131 $correct->cmp( 132 list_checker => $checker, 133 @custom_list_cmp_defaults, 134 @_, 135 ); 136 } 137 138 # 139 # Set this to include any default parameters you want 140 # to include in the custom answer checkers 141 # 142 @custom_list_cmp_defaults = ();
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