ErrorMessageCustomization

Error Message Customization: PG Code Snippet

This PG code shows how to customize (remap) the error messages students receive after submitting an incorrect response or making a syntax error when entering their answer. This requires using MathObjects or a macro file that loads MathObjects, so that a Context is defined. Note that this is an insertion, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.

Problem Techniques Index

PG problem file	Explanation
loadMacros("PGstandard.pl","MathObjects.pl");	Initialization: To be able to customize the error messages students receive, we must be using MathObjects or a macro that loads MathObjects and has a Context.
Context("Numeric"); Context()->{error}{msg}{"Missing operand after '-'"} = "Enter '-1' instead of '-'"; $ans1 = Real("-1"); $ans2 = Formula("x-2");	Setup: First, specify a Context. One way to remap the error message is through the context. In factoring -x+2 as -(x-2), students may enter - instead of -1 in the first answer box and receive the error message Missing operand after '-'. We can replace this error message with "Enter '-1' instead of '-'" via the Context()->{error}{msg} .... code to the left. The replacement error message can be anything you like as long as it is nonempty. To generate a blank error message, use a quoted space " ", not "".
BEGIN_TEXT Factor \( -1 \) from \( -x+2 \). $BR \( -x + 2 = \) \{ ans_rule(5) \} \( \cdot \big( \) \{ ans_rule(10) \} \( \big) \) END_TEXT	Main Text: The problem text section of the file is as we'd expect.
ANS( $ans1->cmp() ); ANS( $ans2->cmp() );	Answer Evaluation: As is the answer.

Problem Techniques Index