Specialized parsers

parserYourModsHere.pl Modifications to the Parser change the way that student responses are interpreted. By convention files that modify the parser are named starting with "parser" -- e.g. parserYourModsHere.pl.

SpecializedContexts Describes another advanced method for customizing MathObjects by modifying the context.

Examples of modifications are give below.

A description of advanced techniques for customizing the parser are at ModifyingParser (Advanced).

Specialized Parser Macro files

Here is a partial list of the parser modifying files.

Use loadMacros("parserAssignment.pl"); to make the parser modifications available for a WeBWorK question.

Check the POD documentation for more examples.

• parserAssignment.pl
  • checks answers of the form [math]y=3x+5[/math] with the LHS of the equation required.
  • follow the link above to see the additional statements that must be inserted in the question to use this file.
• parserAutoStrings.pl
  • parserAutoStrings.pl - Force String() to accept any string as a potential answer.

  AutoStrings()
    -- all strings are accepted
  DefineStrings("string1", "string2")
  DefineStrings(qw(string1 string2)) 
    -- is a quick way to define "legitimate" strings.

• parserCustomization.pl
  • Placeholder for site/course-local customization file.
• parserDifferenceQuotient.pl
  • An answer checker for difference quotients.
• parserFormulaUpToConstant.pl
  • implements formulas ``plus a constant.
  • Students must include the ``+C as part of their answers
• parserFormulaWithUnits.pl
  • Implements a formula with units.
  • For example:

     FormulaWithUnits("3x+1 ft")->cmp
     FormulaWithUnits($a*$x+1,"ft")->cmp

• parserFunction.pl
  • An easy way of adding new functions to the current context.
  • parserFunction("f(x)" => "sqrt(x+1)-2");
• parserImplicitEquation.pl
  • An answer checker for implicit equations.

   Context("ImplicitEquation");
   $f = ImplicitEquation("x^2 = cos(y)");
   $f = ImplicitEquation("x^2 - 2y^2 = 5",limits=>[[-3,3],[-2,2]]);
   $f = ImplicitEquation("x=1/y",tolerance=>.0001);

• parserImplicitPlane.pl
  • Implement implicit planes.

   $P = ImplicitPlane(Point(1,0,2),Vector(-1,1,3)); #  -x+y+3z = 5
   $P = ImplicitPlane([1,0,2],[-1,1,3]);            #  -x+y+3z = 5
   $P = ImplicitPlane([1,0,2],4);                   #  x+2z = 4
   $P = ImplicitPlane("x+2y-z=5");

• parserMultiAnswer.pl
  • Tie several blanks to a single answer checker.
• parserNumberWithUnits.pl
  • Implements a number with units.

   ANS(NumberWithUnits("3 ft")->cmp);
   ANS(NumberWithUnits("$a*$b ft")->cmp);
   ANS(NumberWithUnits($a*$b,"ft")->cmp);

• parserParametricLine.pl
  • Implements Formulas that represent parametric lines.
• parserPopUp.pl
  • Pop-up menus compatible with Value objects.
• parserPrime.pl
  • Defines f'(x) so that students and authors can use the prime notation in defining equations.
  • After loading file use perl command parser::Prime->Enable; to enable the feature.
• parserRadioButtons.pl
  • Radio buttons compatible with Value objects, specifically MultiAnswer objects.
• parserSolutionFor.pl
  • An answer checker that checks if a student's answer satisifies a (possibly non-linear) implicit equation.
• parserVectorUtils.pl
  • Utility macros that are useful in vector problems.