Difference between revisions of "ErrorMessageCustomization"

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(New page: <h2>Error Message Customization: PG Code Snippet</h2> <!-- Header for these sections -- no modification needed --> <p style="background-color:#eeeeee;border:black solid 1px;padding:3p...)
 
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<h2>Error Message Customization: PG Code Snippet</h2>
  
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{{historical}}
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<p style="font-size: 120%;font-weight:bold">This problem has been replaced with [https://openwebwork.github.io/pg-docs/sample-problems/problem-techniques/ErrorMessageCustomization.html a newer version of this problem]</p>
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<h2>Error Message Customization</h2>
   
 
<!-- Header for these sections -- no modification needed -->
 
<!-- Header for these sections -- no modification needed -->
   
 
<p style="background-color:#eeeeee;border:black solid 1px;padding:3px;">
  
<p style="background-color:#eeeeee;border:black solid 1px;padding:3px;">
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<em>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 <b>insertion</b>, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.</em>
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<em>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.
  +
<br />
  +
<br />
  +
You may also be interested in [http://webwork.maa.org/wiki/AnswerHints AnswerHints]
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</em>
 
</p>
  
</p>
   
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<td style="background-color:#ddffdd;border:black 1px dashed;">
  
<td style="background-color:#ddffdd;border:black 1px dashed;">
 
<pre>
  
<pre>
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loadMacros("MathObjects.pl");
  
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DOCUMENT();
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loadMacros(
  +
"PGstandard.pl",
  +
"MathObjects.pl",
  +
);
  +
TEXT(beginproblem());
 
</pre>
  
</pre>
 
</td>
  
</td>
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Context("Numeric");
  
Context("Numeric");
 
Context()->{error}{msg}{"Missing operand after '-'"}
 
Context()->{error}{msg}{"Missing operand after '-'"}
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= "Enter '-1' instead of '-'";
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= "Enter '-1' instead of '-'";
   
−
$ans1 = Real("-1");
 +
$ans1 = Real(-1);
 
$ans2 = Formula("x-2");
  
$ans2 = Formula("x-2");
 
</pre>
  
</pre>
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<b>Setup:</b>
 
<b>Setup:</b>
 
First, specify a Context. One way to remap the error message
  
First, specify a Context. One way to remap the error message
−
is through the context. In factoring -x+2 as -(x-2), students
 +
is through the context. In factoring <code>-x+2</code> as
  +
<code>-(x-2)</code>, students
 
may enter <code>-</code> instead of <code>-1</code> in the
 
may enter <code>-</code> instead of <code>-1</code> in the
 
first answer box and receive the error
 
first answer box and receive the error
 
message <code>Missing operand after '-'</code>. We can replace
  
message <code>Missing operand after '-'</code>. We can replace
 
this error message with <code>"Enter '-1' instead of '-'"</code> via
  
this error message with <code>"Enter '-1' instead of '-'"</code> via
−
the <code>Context()->{error}{msg} ....</code> code to the left.
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the <code>Context()->{error}{msg}...</code> code to the left.
 
The replacement error message can be anything you like as long as
  
The replacement error message can be anything you like as long as
 
it is nonempty. To generate a blank error message, use a quoted
  
it is nonempty. To generate a blank error message, use a quoted
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space <code>" "</code>.
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space <code>" "</code>, not <code>""</code>.
 
</p>
  
</p>
 
<p>
  
<p>
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Notes: on using this and related Contexts.
  
  +
For another way to customize the error message, see the
  +
Answer Evaluation section below.
 
</p>
  
</p>
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</td>
  
</td>
 
</tr>
  
</tr>
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<td style="background-color:#ffdddd;border:black 1px dashed;">
  
<td style="background-color:#ffdddd;border:black 1px dashed;">
 
<pre>
  
<pre>
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Context()->texStrings;
 
BEGIN_TEXT
  
BEGIN_TEXT
 
Factor \( -1 \) from \( -x+2 \).
  
Factor \( -1 \) from \( -x+2 \).
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\( \big) \)
  
\( \big) \)
 
END_TEXT
  
END_TEXT
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Context()->normalStrings;
 
</pre>
  
</pre>
 
<td style="background-color:#ffcccc;padding:7px;">
  
<td style="background-color:#ffcccc;padding:7px;">
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ANS( $ans1->cmp() );
  
ANS( $ans1->cmp() );
 
ANS( $ans2->cmp() );
  
ANS( $ans2->cmp() );
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  +
ENDDOCUMENT();
 
</pre>
  
</pre>
 
<td style="background-color:#eeccff;padding:7px;">
  
<td style="background-color:#eeccff;padding:7px;">
 
<p>
  
<p>
 
<b>Answer Evaluation:</b>
  
<b>Answer Evaluation:</b>
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As is the answer.
  
  +
Another way to customize the error message <code>Missing operand after '-'</code> would be to use a post-filter to remove the message after the answer has been graded. The <code>answerHints.pl</code> macro provides one way to do this, but it is probably just as easy to do it manually, as in:
  +
<pre>
  +
ANS($ans1->cmp->withPostFilter(sub {
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my $ans = shift;
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$ans->{ans_message} = "Enter '-1' instead of '-'"
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if $ans->{ans_message} eq "Missing operand after '-'";
  +
return $ans;
  +
}));
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</pre>
  +
 
</p>
  
</p>
 
</td>
  
</td>
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[[Category:Problem Techniques]]
  
[[Category:Problem Techniques]]
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  +
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<ul>
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<li>POD documentation: [http://webwork.maa.org/pod/pg/macros/answerHints.html answerHints.pl]</li>
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<li>PG macro: [http://webwork.maa.org/viewvc/system/trunk/pg/macros/answerHints.pl answerHints.pl]</li>
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</ul>

Latest revision as of 08:18, 28 June 2023

This article has been retained as a historical document. It is not up-to-date and the formatting may be lacking. Use the information herein with caution.

This problem has been replaced with a newer version of this problem

Error Message Customization


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.

You may also be interested in AnswerHints

Problem Techniques Index

PG problem file Explanation 
DOCUMENT();
loadMacros(
  "PGstandard.pl",
  "MathObjects.pl",
);
TEXT(beginproblem());

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 "".

For another way to customize the error message, see the Answer Evaluation section below. 

Context()->texStrings;
BEGIN_TEXT
Factor \( -1 \) from \( -x+2 \).
$BR
\( -x + 2 = \) 
\{ ans_rule(5) \} 
\( \cdot \big( \) 
\{ ans_rule(10) \} 
\( \big) \)
END_TEXT
Context()->normalStrings;

Main Text: The problem text section of the file is as we'd expect. 

ANS( $ans1->cmp() );
ANS( $ans2->cmp() );

ENDDOCUMENT();

Answer Evaluation: Another way to customize the error message Missing operand after '-' would be to use a post-filter to remove the message after the answer has been graded. The answerHints.pl macro provides one way to do this, but it is probably just as easy to do it manually, as in: 

ANS($ans1->cmp->withPostFilter(sub { 
  my $ans = shift; 
  $ans->{ans_message} = "Enter '-1' instead of '-'" 
    if $ans->{ans_message} eq "Missing operand after '-'";
  return $ans; 
}));

Problem Techniques Index


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