
CTAT 3.1 Function Reference  
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Description
CTAT Functions  

edu.cmu.pact.BehaviorRecorder.ProblemModel.Matcher.Functions 
Java Math and String Functions Usable from CTAT  

java.lang 
These pages document functions that can be used within CTAT formulas—expressions you
can write for steps in an exampletracing tutor that enable the tutor to accept a wider variety of
student input. Formulas enable you to combine the values of inputs on other steps, studententered
input on the current step, and the contents of interface widgets (such as text fields) in evaluating
correctness. They can also be used to accept a variety of inputs, such as a number with a comma
and/or a dollar sign, or an expression that is not simplified but is otherwise correct. Formula
results can be embedded in the text of hint and other feedback messages by inserting the
formula expression within special brackets. And a formula result can rewrite a student input field,
so that, e.g., the tutor can display 8
if the student entered 6+2
.
For more information on how to write formulas and where to enter them, see the section Generalizing an exampletracing tutor with formulas in the CTAT Users Guide.
Note: When using any of the Java String or Math functions from within a CTAT
formula, specify the string or number you want to manipulate as the first argument to the
function. For example, to use String.replaceAll
to remove any leading spaces or dollar
signs in studententered input, use the formula replaceAll(input, "^[ $]*", "")

CTAT 3.1 Function Reference  
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