Release notes for WeBWorK 2.4.9

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This article has been retained as a historical document.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.

See more recent notes in Category:Release_Notes

                         Online Homework Delivery System                        
                                  Version 2.4.9                                

                    Copyright 2000-2010, The WeBWorK Project                    
                              All rights reserved.                              


Release date: 2010 December 1
SVN tag: rel-2-4-9 
SVN url/branch:  module
Modules:    webwork2   pg

 IMPORTANT!! Be sure to inspect changes in the configuration files when upgrading to this release.


For Students

New features 2.4.9

Tool tips for previewing answers

  • The "preview answers" and "correct answers" fields which respond to student entries are now typeset. Hovering over the fields will bring up a tooltip with the entry in it's original unformatted form. The tooltip contents can be copied and pasted back into answer blanks if desired.
  • This feature uses the open source tooltips javaScript suite written by Walter Zorn. The code is stored in the file webwork2/htdocs/js/wz_tooltip.js.
  • This makes the "Entered" field redundant since it's content is identical to the tooltip which comes up when hovering over the "preview answers" field. It's likely that we'll remove the "Entered" field at some later date unless there is good reason to keep it.

Hardcopy changes

  • Added separate checkbox for printing answers entered by students for any hardcopy (including quizzes). The print correct answer checkbox remains as well. The "print student answers" box is checked by default.
  • 7/17/09 Allow instructor to print hardcopy for student by adding effectivePermissionLevel (level of user to whom question has been assigned) and permissionLevel (user viewing the assignment) to the PG environment.

MathJax option

  • MathJax (a successor to jsMath) can now be selected as a means of displaying the mathematics equations.
  • See MathJax for more details.

For Course Instructors

New features added to 2.4.9

Changes to course administration

  • Added buttons (javaScript) to select all or unselect all checkboxes on the classlist and homework set editor pages

Extensions to "Email the instructor"

  • The standard behavior of the "Email the instructor" button remains the same. Pressing the button brings up a form which the student fills out and submits. The contents is emailed to the appropriate instructors determined by the settings made in Course Configuration. Other settings such determining the email target for a given section are set in global.conf.
  • If $courseURLs{feedbackURL} is not empty then the form filled out by the student is submitted to that URL for processing. For example this could be used to submit the email for posting to a joint Moodle wiki where the message could be viewed and replied to by the entire class.
  • If $courseURLs{feedbackFormURL} is not empty then the button calls up the form supplied by that URL. For example this could be used to call up the welcome form for a tutoring site (The video session MathNerds.com_(Video) describes the interaction of WeBWorK and the free online tutoring service MathNerds ).

While these preferences can be set on a course by course basis it is probably best if the changes are made to course.conf by someone with command line access (e.g. the site administrator) in case something goes wrong. There is no safety net (from the web) when modifying course.conf.

Extended and unified naming conventions

  • Set names can contain alphanumeric characters, hyphens(-), underbars(_), periods(.), and commas(.), colons (:), and slashes(/).
  • User names can contain alphanumeric characters, hyphens(-), underbars(_), periods(.), and at signs(@). This allows the use of most email addresses as login user_id's. For safety the at sign, comma and period are converted to underbars when labeling on-the-fly graphs.
  • Problem_id's can contain only numbers.
  • IP's (used in proctored gateway quizzes) can contain alphanumeric characters, hyphens(-), underbars(_), periods(.), commas(.), colons (:), and slashes(/).
  • FileManager will allow commas in directory names.
  • Periods in set names are automatically converted to _ when printing hardcopy to avoid incompatibility with TeX. Still it is probably wise to limit set names characters to letters, numbers and underbars to avoid conflicts with auxiliary tools such as TeX, and mySQL.
  • Image names can contain underbars and still act peacefully with TeX (at least most of the time :-) ).
Technical note:
In conjunction with this unified naming convention a centralized macro in, check_user_id, is called to make sure that
user names conform to the standards above.  This is also done when uploading classlists.  It is
expected that this will eliminate a previous bug which allowed student ID's with non-English characters
to corrupt the database resulting in non-deletable users with "diamond" characters in their user names.

see Naming_conventions for further updates.

User Interface Changes

  • HINTS and SOLUTIONS now are always shown to instructors -- this makes it easier to proof read all parts of a WeBWorK question including the solutions and instructions sections.
  • There is now a cleaner syntax for the hints and solution sections: BEGIN_HINT / END_HINT and BEGIN_SOLUTION / END_SOLUTION.
BEGIN_HINT is translated into TEXT(HINT(EV3P(<<'END_HINT'))); which is unwieldy to type directly. 
BEGIN_SOLUTION has a similar translation.

NPL additions

We have added libraries of questions donated by these institutions to the NationalProblemLibrary:

  • FortLewis -- from Paul Pearson at Fort Lewis College in Durango, CO
  • LoyolaChicago -- Loyola University in Chicago
  • Michigan (questions drawn from the Gleason, Hughes- Hallet, et. al. text) questions written by Gavin LaRose at U. of Michigan
  • NationalProblemLibrary questions have been upgraded with many bug fixes and improvements. (thanks to Spyro Roubos)
  • Physics problems are now available -- adapted by the Frank Wolfs (at University of Rochester) and his students from the CAPA physics problem collection. These can be downloaded from the rochester section of the svn repository but they are not yet part of the NationalProblemLibrary. (tagging remains to be done.)

Model Course Examples

We are collecting examples of questions from the NationalProblemLibrary which are appropriate to courses typically taught at colleges and universities in the US. Here is our first collection for 1st semester calculus.

  • This first model calculus problem collection was taken from a first semester "Engineering calculus" course taught at the University of Rochester in 2007 using Stewart's Calculus text book.
  • This collection also indicates the interaction of Moodle and WeBWorK. An outline for the course with chapters from Stewart is listed in the week by week syllabus page of Moodle. Each week has a link to the corresponding homework set in WeBWorK.
  • You can log in using the guest login button.

Encouraging best practices in coding WeBWorK problems.

  • The most important aspect of this collection is that the questions were rewritten to use MathObjects where ever possible and the questions represent the current "best practices" for writing new WeBWorK questions (as of 2010).
  • You can view the code for each question using the "Show Problem Source" button.
  • This model calculus problem collection (use guest login button) and
  • This wiki's Problem Techniques Category provide good resources for authors just beginning to write WeBWorK questions as well as for authors with more experience.
  • Another useful reference is the PGLabs page where one can try out snippets of PG code without creating an entire problem.

Moodle wwassignment/ WebworkSOAP changes

The WeBWorK/Moodle_bridge(Video) describes using Moodle and WeBWorK together.

mod/wwassignment php files changed in Moodle

  • 9/20/2009 correctly calculate point problems for grades rather than just the number of correct answers.
  • 9/20/2009 only administrators can edit a wwlink block to connect to a webwork site or course. (Instructors are not given permission to do this.)
  • 10/1/2009 Modify upgrade_dirty_sets() subroutine so that only wwassignment modules that have been touched since the last cron job are updated. Before this all grades in all courses (even archived courses) were updated causing unnecessary load on the server.
  • 10/03/2009 Refresh calendar events for the course (part of upgrade_dirty_sets)
  • 9/27/2010 Added a line that prevents errors when one of the moodle courses is no longer available.- The grade transfer process is skipped in this case.
  • 9/27/2010 make modifications that allow gateway quizzes to be initiated from Moodle.
  • 9/27/2010 Added to the grade_sets routine so that gateway quizzes can also have their grades returned to Moodle (first added 9/27/2010 in branches/gage_dev)


  • A new method of storing data for past answers has been implemented with this version of WeBWorK. Past answers entered into courses created with a previous version of WeBWorK here will be lost once a new answer is entered. There will be a warning message the first time this is done. It will read something like:
* problem fetching answers -- possibly left over from base64 days. Not to worry -- press "Preview" or "Submit"  
and this will go away permanently for this  question. Storable binary ....

This will only be noticeable to instructors viewing old courses or to students who are viewing problems from an old course which they answered using a previous version of WeBWorK. This warning message goes away as soon as the question is answered once using the new system.

For WeBWorK question authors

Best practices examples

Where to find advice on best practices for coding WeBWorK problems.

  • The most important aspect of the model calculus problem collection (login as guest) described above is that the questions were rewritten to use MathObjects where ever possible and the questions represent the current "best practices" for writing new WeBWorK questions (as of 2010).
  • You can view the code for each question using the "Show Problem Source" button.
  • This model calculus problem collection and
  • This wiki's Problem Techniques Category provide good resources for authors just beginning to write WeBWorK questions and for authors with more experience.
  • Another useful reference is the PGLabs page where one can try out snippets of PG code without creating an entire problem.

New Help Files for students

This new feature makes it easy to provide answer formatting information and other help for students in a consistent manner.

  • Example: \{ AnswerFormatHelp("formulas") \} $PAR
  • The helpFiles currently available are
angle,  decimal,  exponent,  equation,  formula,  fraction,  
inequalit,  interval,  log,  limit,  number,  point,  syntax,  unit,  vector

Thanks to Paul Pearson for the helpFile macros.


 #  Usage
 #  loadMacros("","",);
 #  TEXT(beginproblem());
 #  \{ AnswerFormatHelp("formulas") \} $PAR
 #  \{ AnswerFormatHelp("equations","help entering equations") \} $PAR
 #  \{ AnswerFormatHelp("formulas","help (formulas)","") \}
 #  First example: use defaults.
 #  Second example: use customized text displayed to the student
 #  as the html link.
 #  Third example: additionally points to a particular URL where 
 #  html help files are located. The URL must end with a forward slash.
 #  The third method is not recommended, as a universal, site-wide,
 #  or course-wide solution obtained by modifying the value of
 #  $helpdir in NPL/macros/FortLewis/ is preferable to setting the
 #  URL in every individual PG file manually.

The default location for help files is in the directory webwork2/htdocs/helpFiles/.

Client editor features

There is now support for authoring and editing WeBWorK questions on your local computer using your favorite editor. Once you have written the question you can send it to a WeBWorK site for conversion into HTML. The html is returned to your computer where it is displayed in your browser.

  • The script ...webwork/clients/ will render a WeBWorK problem submitted from the command line.
  • It does this by making a webservice call to a WeBWorK site via the XML_RPC protocol requesting that the contents be rendered as a WeBWorK PG question.
  • The script will work with most modern editors to allow you to check a WeBWorK question from within an editor such as BBedit, emacs, or gedit with a single command key. This allows you to use all of the features of your favorite editor while creating new WeBWorK questions and to store the file containing the question in a directory on your desktop machine.
  • For minor corrections of WeBWorK questions already in a homework set it is still quicker to use the PG editor in WeBWorK itself.
  • For those using Firefox the plug-in "It's all Text" allows you to edit TEXT AREA regions of an HTML form in your favorite editor. I often do this when making extensive changes to a WeBWorK question already in a homework set.
  • See Client_Editor for more details on configuration, use and the internal technical details.

New and changed contexts

  • Almost all of the Context and Parser files in pg/macros have been created or updated since release 2.4.7. This greatly increases the ease with which answers can be checked.
  • Details can be found on the Specialized_contexts page.

Additional changes to macro files

  • Status of
  • Moving common macros from NPL/macros/Union to pg (display table and list macros)
  • Move to pg/macros directory

DEBUG and WARNING channels

There are two new channels for transmitting warning or debug information from inside a WeBWorK problem to the outside. These are just preliminary versions and the exact behavior may change over time. At the moment they behave in the same way and simply print their message at the end of the problem.

 DEBUG_MESSAGE("This is a message used while debugging a WeBWorK question -- for example it might show the value of $myVariable");
 WARNING_MESSAGE(" This message might be left permanently in a WeBWorK question to warn about some 
                                         unexpected error -- e.g. division by zero ");

The main reason for having two of them, is that one can do a quick search and replace to comment out the debug messages, changing DEBUG_MESSAGE to #DEBUG_MESSAGE, while leaving the WARNING_MESSAGE() constructs in place.

You can still use the perl

warn "this is a warning message";

but it seems cleaner to have a separate channel for WeBWorK problem messages that doesn't have to conform to perl's rules for warn. In particular the DEBUG_MESSAGE and WARNING_MESSAGE constructs do not print to the apache error_log while perl's warn does and results in a lot of not very meaningful clutter for the system admin to look at.

PG language enhancements


  • While applets have been included in WeBWorK questions for some time now, keeping the applets running smoothly in a multitude of browsers is a challenge.
  • There has been steady progress in constructing an API that shields the WeBWorK author from messy details such as finding the precise url for the applet, verifying that the applet is properly loaded before commands are sent to it and so forth. No doubt more will need to be done as authors explore the rich user interface that can be developed by adding applets to WeBWorK questions (and to WeBWorK hints and solution sections).
  • We currently have support for 4 types of applets: Java applets, Flash Applets, HTML5 applets and applets created with GeoGebra.
  • One striking use of applets is to ask a question which the student is to answer by

drawing a curve representing a function.

  • An example of how to include an interactive GeoGebra applet into a WeBWorK question and set parameters in the GeoGebra applet from WeBWorK is now available in the Problem Techniques section of the documentation for Problem Authors: GeoGebra Applets in WeBWorK
  • Details and examples are in the Category:Applets (requires updating for Geogebra and Canvas and graph inputs)

The PGML markdown language

  • These commands developed by Davide Cervone provide a "markdown" language for writing WeBWorK questions.
  • They facilitate the layout of the question on the screen and provide a user interface that feels more like mathematics and less like computer code.
  • This makes it easier to enter and edit standard mathematics questions for those unfamiliar with computer programming languages.
  • To use PGML simply write the question inside BEGIN_PGML / END_PGML instead of the usual BEGIN_TEXT / END_TEXT tags.
  • To get started:
    • There is a video presentation by Davide of the features of PGML and
    • a PGLabs WeBWorK "homework set" which allows you to try out these features as well as a
    • "Power point" presentation (using WeBWorK) of the PGML features.
  • We do not yet have a full course of math problems written using PGML to serve as an example. (Volunteers?)


  • All occurrences of psvnNumber have been replaced by psvn. (This may affect some few problems that referred directly to psvnNumber.)
  • 7/17/09 Allow instructor to print hardcopy for student by adding effectivePermissionLevel (level of user to whom question has been assigned) and permissionLevel (user viewing the assignment) to the PG environment.

PG changes "under the hood"

There have been some major changes to the very basic PG code first written more than 10 years ago in perl 4 before objects became available in perl 5.

For the moment the changes involve rewriting some of the initial code to use perl objects instead of simulating objects by defining specialized namespaces. The new objects currently simulate the previous behavior but they also lay the foundation for future changes which will make the PG language more robust.

The changes contemplated mostly involve code previously kept in the file dangerousMacros which govern how macro files are located and loaded and how auxiliary files: applets, PNG or GIF files, auxiliary HTMl files, are kept track of. (The alias() command). The ways in which the answer blanks and the response evaluators are matched up will also be upgraded. This will involve changes to pg/lib/WeBWorK/PG/

Potential changes needed to adjust to the new structure of PG

So far there is only one.

  • Use ANS_NUM_TO_NAME(1) macro instead of calling AnSwEr1 directly (the label automatically assigned to answer blanks can change -- it is dangerous over the long term to assume that the label format is fixed.).

Following this practice will also make the question compatible with Gateway quizzes.

New files added

  • These are the files where the new objects are defined. Their names are mostly of concern to site administrators who need to make adjustments in global.conf
  • The modules PGcore, PGalias, PGresource PGloadfiles PGanswergroup, PGresponsegroup have been added to the WeBWorK code base.
Those macros or questions which made extensive use of "internal" macros in or may still find those capabilities available through the $PG object placed in the
the PG environment of each WeBWorK question. (see comments in the new modules above.)
The macros in pg/macros and those stored in the NationalProblemLibrary 
have already been modified to reflect these changes.  The graders in have
also been updated so that they don't make hidden assumptions about the labels automatically
generated for answer blanks.

For site administrators

We have switched to using SVN instead of CVS for this and all future updates

The Moodle module updates will remain in our CVS repository as long as Moodle keeps its code in a CVS repository. This allows a single cvs update to update both Moodle and the wwassign module.

It is pretty easy to switch over to the SVN updating mechanism. The instructions are at

Changes between 2.4.7 and 2.4.9

Changes in Configuration files

It is important to compare the global.conf.dist files with global.conf (and similarly database.conf.dist and database.conf and webwork.apache2-conf.dist and webwork.apache2-conf ). The differences that you recognize as being made to accommodate local settings (e.g. location of standard unix tools, or preferences on how webwork behaves) should be preserved in global.conf. New lines appearing in global.conf.dist should probably be transferred over. This is especially true of new permission lines and of new module lines

Here are some of the significant sections of global.conf that have been changed. (This also gives a good overview of what has changed since rel-2-4-7. ) You can get full report of all changes by using the SVN diff facility and comparing the current version with the version from June 2009 when rel-2-4-7 was released.


  1. Control of WeBWorK's email feedback system is enhanced. It is possible to redirect the email to be sent to a url for posting. It is also possible to replace the email form itself with an external url. (Constructed for use by MathNerds)
  2. All urls refering to machines have been changed to machines.
  3. Controls for MathJax (the new upgraded jsMath) have been added in several sections. You can allow the user to chose between jsMath, MathJax and images when viewing equations.
  4. The timezone is initialized to America/New_York by default instead of to blank.
  5. The moodle authen configuration has been removed -- it is no longer used in moodle/webwork installations
  6. There are additional configuration options when using LDAP directly with WeBWorK. (thanks to Mark Hamrick and Jason Aubrey).
  7. "report_bugs" permission defaults to ta now rather than to student.
  8. "download_hardcopy_view_errors" has been added and set to "professor".
  9. The paths to many macro libraries in the NationalProblemLibrary have been added by default. This will lead to fewer surprises when a question written at another school appears not to work because it can't find the appropriate macros.
  10. More URLS have been added to the search paths for applets, including geogebra.
  11. The default positions of the CAPA libraries have been changed.
  12. Added the capability to define problemDefaults for max_attempts and value on a course basis from the web using the Course Configuration page or site wide using global.conf.
  13. Controls for the reducedScoringPeriod have been added. (Less credit if the student hands homework in late.)
  14. Can specify defaultDisplayMatrixStyle in ansEvalDefaults.
  15. IMPORTANT. The "List" module's name has been changed to "ChoiceList" to avoid confusion with the MathObjects "List" object. List is called by Math, Multiple and several other modules but is seldom called directly except in macro files. The macrofiles in the NPL (especially Union) have been modified to accommodate this change. This change will break questions that called List directly but that seems to be a rare occurence.
  16. The modules PGcore, PGalias, PGresource PGloadfiles PGanswergroup, PGresponsegroup, Tie::IxHash have been added. This is the beginning of a major upgrade to the internals of the PG language. It will not affect most users, but it may affect questions or macros that use the lowest level internal functions designed for matching answer blanks with answer evaluators. The macros in the NPL have been modified to accommodate these changes.
  17. Added the module CanvasApplet which implements HTML5 techniques for inputting a graph.
  18. Added -d flag to lwp-request to reduce overhead when checking urls with checkurl

Changes in site administration operations

We continue to make incremental changes to increase the power of administering WeBWorK from the web instead of from the command line. The archive and unarchiving process has been made more robust. The integrity of the database structure is checked before archiving and when unarchiving a course.

  1. The automatic integrity checking of each course when the admin homepage loads has been discontinued. The integrity is now checked only when you choose the "Upgrade Course" tab. This speeds up loading of the admin site when there are many courses on the site.
  2. You will need to upgrade each active course when upgrading from 2.4.7 to 2.4.9 since the reducedScoringPeriod feature has added extra fields to the database.
  3. The Upgrade Course allows one to select multiple courses for upgrading. The course's integrity -- the agreement between the courses data structure in the database and the datastructure defined in database.conf -- is analyzed as well as the existence and permissions set for the various directories in the course. Simple and safe fixes can then be performed by clicking the upgrade course button. More complicated fixes must still be performed from the command line since a bad fix is usually worse than no fix at all.
  4. Multiple courses can be selected for archiving. Each one is screened and approved individually but the list of courses to work on is selected at the start. There is a known bug in the process which stops work on the remaining list of archive courses if one declines to archive one of them.
  5. An instructor can archive their own course from the File Manager page. This allows them to back up courses and save them for a later semester. The integrity of the course is automatically checked and updated if necessary (and possible). There is no opportunity to decide not to update. Only administrators with command line access can unarchive a course.
  6. The Upgrade Course facility means that the command line module is no longer used for upgrades. It might be needed if one is sequentially updating a release that is more than 3 years old.
  7. It is possible to access the integrity subroutines from the command line and to build custom command line scripts which batch process the archiving, upgrading and unarchiving of courses. -- for details see the forum and the wiki -- for descriptions of how this has been done at individual sites. These scripts usually need to be modified for use at a new site, but they provide a starting point.


  1. Removed the possibility of selecting moodle_sql which is now obsolete. Only one schema: sql_single is currently being used.

LDAP features


  • WebworkWebservice/WebworkSOAP configuration -- there is one URL that is not yet configured automatically. In the file lib/WebworkSOAP/ the RPC_URL constant needs to be changed from "localhost" to the url for the WeBWorK site.
  • If you edit a student from the classlist page then their status may be reset to guest (the lowest -5) because the student status of 0 is incorrectly read as blank. The correct workaround for this "feature" depends on which version of is being used. The changes are around line 1514 of The changes work for 3.42 but the original line on 1514 works with CGI 3.49 and the changed line does not. This is recognized as a problem by maintainers and we don't yet have code that will work with both versions of
1514				default => $default,	
  is changed to
1514				-default => [$default], # force default of 0 to be a selector value (instead of 
1515				                        # being considered as a null -- now works with CGI 3.42
  • There is a bug in the way mysql flags work. Changes may need to be made for the version used on your server. (The change is in Schema/NewSQL/ and involves the flags: --defaults-extra-file and --defaults-file which are used to retrieve temporarily cached credentials for accessing mysql.)
  • There is a bug in version 2.27 which makes it incompatible with WeBWorK. The symptom is that any action involving a MathObject, such as answering a WeBWorK question -- will send the child process serving that request into an infinite loop. Versions of before 2.23 appear to work fine. version 2.29 (the most recent as of this writing) works for most problems but will throw errors on specific WeBWorK problems - particularly ones using graphics.
  • A file labeled which is version 2.16 is included with this distribution. At the moment the lines use Safe; have been changed to use WWSafe; in these files
  • (Thanks to Zig Fiedorowicz and Geoff Goehle for research into this problem. Other references: and is used by WeBWorK to provide a clean namespace for each new problem and to prevent the accidental use of perl commands by webwork question authors that could harm the unix environment. In general it is not considered by the perl monks as a sufficient barrier against determined hacking attempts however it has worked well for us over the last 14 years.

Technical Bug fixes

  • 8/29/09 fixed bug in hardcopy preventing printing when no set was selected.
  • 9/24/09 fixed bug in CourseIntegrityCheck that confused msql tables of math101 and math101_fall09
  • 9/30/2009 First of changes working around bugs in that handle student permissions badly -- in pop up menus because they have permission level 0. This might require tweaking depending on the copy of used on your machine.
  • 1/23/2010 second attempt to fix the CGI bug.
  • 12/16/2009 Fixed major security hole -- only files below templates directory should be accessible from the homework set detail page (described in ).
  • 11/4/09 fixed bug in useBaseTenLog
  • 1/11/2010 Fix bug that gave error message when problem had not been assigned to any user.
  • 1/11/2010 Give more reasonable warning message if timezone is not correctly defined.
  • 5/13/2010 fixed mysqldump bug that affects archiving. (changes in Schema/NewSQL/ - work around for non-documented behavior of --defaults-file and --defaults-extra-file flags in calling mysql from the command line. This may need to be adjusted on different servers.
  • 5/14/2010 fixed typo in num_sort
  • 5/18/2010 insure that hardcopy error files can be read by the instructor from the web.
  • 6/8/2010 NPL update fix (from Gavin)
  • 7/20/ update findAppletCodebase (in
  • 7/21/2010 bugfix to ww_applet_support.js

Release_notes_for_WeBWorK_2.4.7 and previously.

Error Messages

DBD::mysql::st execute failed: Unknown column 'merge1.enable_reduced_scoring' 
in 'field list' at  /opt/webwork/webwork2/lib/WeBWorK/DB/Schema/NewSQL/ line 814.

This means the courses created with previous versions of WW need to be upgraded. This is done from admin "course". See items 1. and 2. at Release_notes_for_WeBWorK_2.4.9#Changes_in_site_administration_operations above.

Upgrade Instructions

See Upgrading_WeBWorK

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