Preg question type is a question type using regular expression pattern matching to find if studen response is correct. It is use Perl-compatible regular expressions dialect. For detailed description of regular expression syntax see http://www.nusphere.com/kb/phpmanual/reference.pcre.pattern.syntax.htm

Authors:
# idea, design, question type code, regex parsing and error reporting - Oleg Sychev;
# regex parsing, DFA regular expression matching engine - Dmitriy Kolesov.
We would gladly accept testers and contributors (see [[#Development plans|development plans]] section) - there is still more to be done than we have time.

For now new code with all this functionality located in the HEAD branch of preg question type (you could also download it from the [http://moodle.org/mod/data/view.php?d=13&rid=1901&filter=1 Modules and Plugins database] using 'latest version' link. It is works with Moodle 2.0. The code considered BETA quality - use it with care! If you find any bugs please report them on the tracker.

===Understanding expressions===
The regular expressions - as any '''expressions''' - are just a bunch of '''operators''' with their '''operands'''. Don't worry - you all learned to master arithmetic expressions from chilhood and regular ones are just as easy - if you look on them from the right angle. Learn (or recall) only 4 new words - and you are a master of regexes with very wide possibilities. Don't find that angle, and regular expressions could forever remain vast menace where only a few steps are sure. Let's go?

Look at a simple math expression: '''x+y*2'''. There are two '''operators''' there: '+' and '*'. The '''operands''' of '*' is 'y' and '2'. The '''operands''' of '+' is 'x' and result of 'y*2'. Easy?

Thinking about that expression deeper we could found, that there is a definite '''order of evaluation''' there, governed by operator's '''precedence'''. '*' has a precedence over '+', so it is evaluated first. You could change order of evaluation using brackets: '''(x+y)*2''' will evaluate '+' first and multiply it's results on the 2. Still easy?

One more thing we should learn about operators: their '''arity''', which is just the number of operands required. In example above '+' and '*' are '''binary''' operators - they both take two operands. Most arithmetic operators are binary, but minus has '''unary''' (single operand) form, like in this equation: '''y=-x'''. Note that unary and binary minuses work differently.

Now any epxression are just lego game, where you set a sequence of '''operators''' with correct number of '''operands''' for each ('''arity'''), taking heed of their order of evaluation using their '''precedence''' and brackets. Arithmetics expressions are for evaluating numbers. Regular expressions are for finding pattern matches in the strings, so they naturally use another operands and operators - but they are governed by the same rules of precedence and arity.

===Regular expressions===
The goal of a regular expressions is a pattern matching in the strings. So their '''operands''' are characters or characters set. '''A''' is a regular expressions too and it matches with single character 'A'. There are several way to define a character set, described below. Special characters, used to write operators,must be '''escaped''' when used as operands - preceded by backslash. Math expressions never had escaping problems since their operands (numbers, variables) are constructed from different characters than operators (+,- etc), but setting pattern for matching you should be able to use any character as operand.

Still, pattern that match only with one character isn't very useful. So there comes '''operators''' that allows us to define expression matching with string of a several characters.

====Operands====
You could use those operands in you expressions:
# ''simple characters'' match with themselves
# ''escaped special characters'' if you need to use character with special meaning (like |, * or bracket) just as usual character to match you should preceed it by backslash: '''a\*''' matches with a* (while '''a*''' matches with a zero or more times), backslash is a special character too and should be escaped '''\\''' matches with \
# ''character classes'' you could specify a number of possible characters in one place in square brackets:
#* '''[ab,!]''' matches with a or b or , or !
#* ''ranges'': '''[a-szC-F0-9]''' you could specify ranges for letters and digits in character classes, mixing them with single characters
#* ''negative character classes'' starts with ^ '''[^ab]''' means any characters except a and b
#* ''escaping inside character classes'': '''[\-\]\\]''' match with - or ] or \, other characters lost their special meaning inside character class and shoudn't be escaped, but if you want to include ^ in the character class it should not be first
# ''dot meta-character'' '''.''' match with any possible character (except newline, but student coudn't enter it anywhere), you should escape dot '''\.''' if you need to match single dot.

====Operators====
Most common regular expression operators used (could anyone help expand descriptions and examples please?):
# ''concatenation'' - so simple '''binary''' operator that is doesn't have any character at all. Still it is an operator and has it's precedence, which is important if you want to understand where to use brackets. Concatenation allows you to write several operands in sequence:
#* '''ab''' matches with ab
#* '''a[0-9]''' matches with a followed by any digit
# ''alternative'' - '''binary''' operator that lets you define a set of alternatives:
#* '''a|b''' mean a or b
#* '''ab|cd|de''' mean ab or cd or de
#* empty alternative: '''ab|cd|''' mean ab or cd or emptiness (useful as a part more complex expressions)
#* '''(aa|bb)c''' mean aac or bbc - use brackets to outline alternative set
#* '''(aa|bb|)c''' mean aac or bbc or c - typical use of emptiness
# ''quantifiers'' - '''unary''' operator that lets you define repetition of a character (or regular expression) used as it's operands:
#* '''x*''' mean x zero or more times
#* '''x+''' mean x one or more times
#* '''x?''' mean x zero or one times
#* '''x{2,4}''' mean x from 2 to 4 times
#* '''x{2,}''' mean x two or more times
#* '''x{,2}''' mean x from 0 to 2 times
#* '''x{2}''' mean x exactly 2 times
#* '''(ab)*''' mean ab zero or more times, i.e. if you want to use quantifier on more than one character, you should use brackets
#* '''(a|b){2}''' mean aa or ab or ba or bb, i.e. it is repeated alternative, not selection one alternative and repeating it

====Precedence and order of evaluation====
'''Quantifier''' has precedence over '''concatenation''' and '''concatenation''' has precedence over '''alternative'''. Let's look what it means:
# ''quantifier over concatenation'' means quantifiers are executed first and without brackets would repeat only single character:
#* '''ab*''' matches with a followed with zero or more b's
#* changing this using brackets allows us define a string repetition: '''(ab)*''' matches with ab zero or more times
# ''concatenation over alternative'' means you could define multi-character alternatives without brackets (for single character alternatives use character classes, not alternative operators) but should use brackets when you need to add something to the alternative set:
#* '''ab|cd|de''' matches with ab or cd or de
#* '''(aa|bb)c''' matches with aac or bbc - use brackets to outline alternative set
#* '''(aa|bb|)c''' matches with aac or bbc or c - typical use of an empty alternative
# ''quantifier over alternative'' means you should use brackets to repeat an alternative set (not the last character in it):
#* '''ab|cd*''' matches with ab or c followed with zero or more b's
#* '''(ab|cd)*''' matches with ab or cd, repeated zero or more time in any order, like ababcdabcdcd etc
#* note that quantifiers repeats alternative, not the definite selection from it, i.e.:
#*# '''(a|b){2}''' matches with aa or ab or ba or bb, not just aa or bb
#*# use '''a{2}|b{2}''' to match aa or bb only

====Assertions====
''Assertions'' are assertions about some part of the string that doesn't actually goes into matching text, but affects whether matching occur or not.
* ''positive lookahead assert'' '''a+(?=b)''' matches with any number of a ending with b without including b in the match
* ''negative lookahead assert'' '''a+(?!b)''' matches with any number of a that is not followed by b
* ''positive lookbehind assert'' '''(?<=b)a+''' matches with any number of a preceeded by b
* ''negative lookbehind assert'' '''(?<!b)a+''' matches with any number of a that is not preceeded by b

====Matching====
'''Matching''' means finding a part of the student answer (or a whole answer) that suited the regular expression. This part called a '''match'''.

You should enter regular expressions as '''answers''' to the question without modifiers or enclosing characters (modifiers would be added for you by question - '''u''' added always and '''i''' in case-insensitive mode). You should also enter one correct response (that matches at least one 100% grade regular expression) to be shown to the student as '''correct answer'''. The question would get use all regular expressions in order to find first full match (full for expression, but not necessary all response - see [[#Anchoring|anchoring]]) and give a grade from it. If there is no full match and engine supports partial matching (see [[#Hinting|hinting]]) than partial match that is shortest to complete would be choosen (for displaying a hint, zero grade is given) - or the longest one, if engine coudn't tell which one would be shortest to complete.

====Anchoring====
Anchoring sets restrictions on the matching process:
* if a regular expression starts with '''^''' the match should start at the start of the student's response;
* if a regular exhression ends with '''$''' the match should ends at the end of the student's reponse;
* otherwise regular expression match could be contained anywhere inside student response.

If you set '''exact matching''' options to yes (default setting), the question would add ^ and $ in each regular expression for you. However, you may prefer to use some non-anchored regexes to catch common errors and give feedback while using manually anchored expression for grading.

===Hinting===
Some matching engines could support hinting (not easy thing to do on the PHP at all) in adaptive mode.

Hinting starts with '''partial matching'''. When a student enters a partially correct answer, partial matching could find that response starts matching and on some character broke it. Consider you enter expression:
'''are blue, white(,| and) red'''
and student answered
they are blue, vhite and red
Partial matching will find that partial match is
are blue,
Remember, the regular expresion in unanchored so the match shouldn't start with the start of the student response. While using just partial matching the student will be shown correct and incorrect parts:
they are blue, vhite and red
When hinting is available, student will have '''hint''' button by pressing which he receive a hint with one next correct character, highlighted by background coloring:
they are blue, wvhite and red
You should typically set hint '''penalty''' more than usual question '''penalty''', because they are applied separately: usual penalty for an attempt without hinting, while hint penalty for an attempt with hinting.
Preg question doesn't add hint character to the student's response (like regex question do it), showing it separately instead for a number of reasons:
# it is student's responsibility whether he want to add hinted character to the his response (and some more possibly);
# it slightly facilitates thinking about hint, since when the response is modified it is too easy to repeatedly press '''hint''', which is not a desirable behavour usually.
When possible (if question engine supports it), hinting choosing a character that leads to shortest path to complete a match. Consider this response to the previous regular expression:
are blue, white; red
There are two possible hint characters: ',' or ' '. The question will choose ',' since it leads to the shortest path to complete a match, while ' ' leads to a path 3 characters longer.

It is possible that not all regular expressions will give 100% grade. Consider you add an expression for the students with bad memory:
'''are white(,| and) red'''
with 60% grade and feedback about forgetting ''blue''. You may not want hinting to lead student to the response
are white, red
if he entered
are white, oh I forgot other colors.
'''Hint grade border''' controls this. Only regular expressions with grade greater or equal than hint grade border would be used for partial matching and hinting. If you set hint grade border to 1, only 100% grade regular expression would be used to hinting, if you set it to 0,5 regular expressions with 50%-100% grades would be used and 0%-49% would not. Regular expressions not used for hinting works only when they have a full match in the student response.

===Subpattern capturing and feedback===
Any pair of round brackets in the regular expressions are considered a '''subpattern''' and when doing matching engine (supporting subpatterns) remember ('''capture''') not only whole match, but it's parts corresponding to all subpatterns. Subpatterns can be nested. If subpattern is repeated (i.e. have quantifier), than only last match of all repeats will be captured. If you want to change order of evaluation without defining a subpattern to capture (which will speed up processing), you should use (?: ) instead of just ( ). Asserts don't create subpatterns.

Subpatterns are counted from left to right by opening brackets. Precisely '''0''' is the whole match, '''1''' is first subpattern etc. You could insert them in the ''answer's feedback'' using simple placeholders: '''{$0}''' is replaced by the whole match, '''{$1}''' by first subpattern value etc. That can improve the quality of you feedback. Placeholders won't work on the ''general feedback'' because different answers could have different number of subpatterns.

'''PHP preg engine''' support full subpattern capturing. '''DFA''' engine coudn't do it, so you could use only {$0} placeholder working with DFA engine.

Let's look at regex defining an decimal number with optional integral part:
[+\-]?([0-9]+)?\.([0-9]+)
It has two subpatterns: first capturing integral part, second - fractional part of the number.
You writed feedback:
The number is: {$0} Integral part is {$1} and fractional part is {2}
Then entering
123.34
the student will see
The number is: 123.34 Integral part is 123 and fractional part is 34
If no integral part is given, {$1} will be replaced by empty string. There is no way (for now) to erase "Integral part is" under that circumstances - the placeholder syntax may become complex and prone to errors.

===Error reporting===
Native PHP preg extension functions only report if there error in regular expression or not, so '''PHP preg extension''' engine couldn't tell you much about what is error .

'''DFA''' engine use custom '''regular expression parser''', so it supports advanced error reporting. The are several class of potential errors reported:
* unclosed square brackets of character class;
* unclosed opening parenthesis of any sort (different forms of subpatterns and assertions);
* unopened closing parenthesis;
* empty parenthesis of any sort (different forms of subpatterns and assertions);
* quantifiers without operand, i.e. at the start of (sub)expression with nothing to repeat;
* three or more top-level alternatives in the conditional subpattern.
PCRE (and preg functions) treat most of them as '''non-errors''', making many characters meaning context-dependent. For example quantifier {2,4} placed at the start of regular expression lose it's meaning as quantifier and is treated as five-characters sequence instead (that matches with {2,4}). However such syntax is very prone to errors and make writing regular expression harder.

For now I'm vote for reporting errors instead of treating them as literals, even if it means incompatibility with PCRE/preg. If you are stand for or against this decision please write you positions and reasons on the page comments please. It may be best to have two modes, but this literally means two parsers and this is out of current scope of development. There are more pressing issues ahead.

===Matching engines===
Matching engines means different program code that do matching (either by different methods or written by different people). There are no single 'best' matching engine - it depends on the features you want to use and regular expressions engine should handle. They have a different degree of stability and offer different features to use.
====PHP preg extension====
It is based on native PHP preg functions (which is in turn based on the PCRE library). It is supporting 100% perl-compatible regular expression features, been very stable and thoroughly tested. Sadly, PHP functions doesn't support partial matching (while PCRE could), so (unless we storm PHP developers to add support for partial matching) there is '''no hinting''' there. However it will support subpattern capturing. Choose it when you need complex regexp features other engines don't support, subpattern capturing or better performace.

====Deterministic finite state automata (DFA)====
This is a custom PHP code using DFA matching algorithm. It is heavily unit-tested, but considered beta-quality for now. Not all PHP operands and operators are supported, and for some (more exotic) ones support could still differs from standard (especially for non-latin characters). On the bright side it is support '''hinting'''.

Currently supported operands (there would be more):
* single characters
* escaped special characters
* character classes, including ranges and negative classes
* escape sequences \w\W\s\S\t\d\D (WARNING: they probably will not work for Unicode (non-latin) characters for now)
* octal and hexadecimal character codes preceeded by \o and \x
* meta-character . (any character)

Currently supported operators (there would be more):
* concatenation
* alternative |
* quantifiers * + ? {2,3} {2,} {,2} {2}
* positive lookahead assertions
* changing operator precedence ( ) (without subpattern capturing) or (?: )

Features that couldn't be supported by DFA matching at all:
* subpattern capturing
* backreferences

===Development plans===
There is no definite shedule or order of development for those features - it depends on the available time and developers. Many features require complex code to achieve results. If you want to help us with specific feature, please contact question type maintainer (Oleg Sychev) using http://moodle.org messaging.
* Update DFA matching engine to support all operations DFA algorithm could
* Improve Unicode support of custom matching engines
* Add automatic generation of shortest possible correct answer in user-readable form
* Add negative matching answers (AKA "missing words" from Joseph Rezeau question) - depends on developing and checking in extra_answer_fields() code
* Add generation of 'description' for regular expression to facilitate it's editing
* Develop NFA and backtracking matching engines
* Develop more help and examples for the people that don't know much about regular expressions.

[[Category:Contributed code]]

Preg question type

2010-09-21T15:57:22Z

Development:VSTU projects

2010-09-12T20:54:38Z

Oasychev: Created a page with a list of our projects

==Lead: Sychev Oleg Aleksandrovich==
Senior Lecturer of POAS (Software Engineering) department

===Core patches===
# [[Development:Categories editing interface improvment|Improvment of editing interface for category list]]. Moving category anywhere should require only one page reload. Developers: Sychev Oleg, Shkarupa Alex. Status: waiting reviewing!
# [[Development:Javascript-interface for repeat_elements function|Javascript-interface for repeat_elements function]] - adding new blanks to the form shoudn't require page reloads.
# [[Development:Forum thread subscription|Forum thread subscription]] - a long standing request to be able to subscript only to the thread, not whole forum.

===Activity modules===
# [[Development:Assignment development|New assignment-replacement module]] with support for individual tasks (with custom fields), several grading criterions, automatic graders etc. Developers: Sychev Oleg, Erofeev Anatolius.
# [[Development:Subcourse module improvments|Subcourse module improvments]] - improve Subcourse module to get rid of buggy Metacourses and make it actually useful.

===Question types===
# [[Preg question type]] - regular expression question type, developed on more solid algorithmic basis than regex one. Developers: Sychev Oleg, Kolesov Dmitry.
# [[Development:Auto-feedback shortanswer question|Auto-feedback shortanswer question]] shortanswer question which could be able to detect typos and misplaced, missing or extra words and give appropriate feedback.

===Blocks===
# [[Development:Linked activities|Linked activities]] to allow editing properties of multiple activities at once.
# [[Auto role assignment block]] is useful to temporary restrict (or enhance) user abilities while doing something.
# [[Under suprevision block]] is much better than IP filter+time control if you want students to be able to do something only under teacher supervision.

===Libraries===
# [[Development:Auto-backup library]] - adding very small information to install.xml files it is possible to automate many tedious tasks of programming backup/restore for the plugins.

Development:Developer notes

2010-09-12T20:46:16Z

Oasychev: /* Modules and other recognised plugin types */ - separated projects developed by VSTU

'''Note:''' New developer documentation pages should be added to the ''Development namespace'' by typing <code>Development:</code> before the new page name i.e. <code><nowiki>[[Development:New page name]]</nowiki></code>.

This area is for developers to work on various bits of code and documentation as necessary. Once material has matured it should be linked to from the main [[Development:Developer documentation|Developer documentation]] page.

==Core code==

*[[Other lang issues|Language issues]]
*[[Datalib Notes]]
*[[Application/session variables]]
*[[Filters schema]]
*[[Filterall support]]
*[[Groups documentation for module developers]]
*[[Development:Plan to improve ability to delegate administrator tasks to course category level|Plan to improve ability to delegate administrator tasks to course category level]]
*[[Development:Stealth mode and nested activities|Stealth mode and nested activities]]
*[[Development:Enrolment_plugins_2.0|How enrolments should work in Moodle 2.0]]
*[[Development:Redesigning the override roles page|Redesigning the override roles page]]

===Gradebook===

*[[Development:Gradebook_improvements|Gradebook improvements]] - ideas from Petr.
*[[Development:Tim's_Gradebook_thoughts|Tim's Gradebook thoughts]]

==Modules and other recognised plugin types==

===Lesson===

*[[Adding_question_types_to_lesson|Adding question types to lesson module]]
*[[Development:New lesson navigation | New lesson navigation]]
*[[Development:Adding blocks to lesson | Adding blocks to lesson]]

===Quiz & question types===

* [[Development:File storage conversion Quiz and Questions|File storage conversion Quiz and Questions]] - notes for MDL-16094.
* [[Development:How the quiz navigation should work in Moodle 2.0|How the quiz navigation should work in Moodle 2.0]] - MDL-20276.
* [[Development:Moodle 2.0 question bank improvements|Moodle 2.0 question bank improvements]] - including question tagging and improved searchability.
* [[Development:Question_Engine_2|Proposal to change the Moodle Question Engine]] This supersedes
** [[Development:Plans for adaptive mode|Plans for adaptive mode]]
** [[Development:Implementation of true negative marks in MC-type questions|Implementation of true negative marks in MC-type questions]]
* [[Calculated question development]]
* [[Numerical question units and intervals]]
* [[Development:Future question bank/sharing/versioning requirements|Future question bank/sharing/versioning requirements]]
* [[Development:States of a quiz attempt]]
* [[Development:Optional checkbox "This is all my own work" before submitting a quiz]]

===Other activity modules===

*[[Forum development|Forum functional upgrade]]
*[[Wiki development|Wiki module development]]

===Gradebook Plugins===

*[[Development:External Database Plugin]]

===Other===

*[[Blogs and forums|Blogs, forums and the nature of discussion]]
*[[Conditional activities]]
*[[Improved Payment Plugin]]
*[[Development:Moodle-specific customisations to the HTML editor]]
*[[Development:Moodle Automatic Regression Test and Inspection Nit-picker]]
*[[Development: VSTU projects|Projects developed in Volgograd State Technical University]] becomes to many to simple list them on that page.

== Markup & Theming ==
* [[Moodle CSS System]], idea from forum discussion on [http://moodle.org/mod/forum/discuss.php?d=126009 Object Oriented CSS]

==Other==

*[[MoodleDocs development]]
*[[Usability]]
*[[Document Management API]]
*[[wikindx|Possible integration of WIKINDX with Moodle]]
*[[Development:Snapshot - flat HTML export of complete course]]
*[[Development:Offline Moodle | Development:Offline Moodle - A Moodle that runs on a mobile device with the internet]]
*[[Development:A standard set of fixtures for unit tests?|A standard set of fixtures for unit tests?]]

==Archive: past proposals==

===Things that got implemented===

====Core code====

*[[Development:Ajax user selector|Ajax user selector]]
*[[Roles]] - in Moodle 1.7
*[[Moodle forms library]] - in Moodle 1.8
**[[Martin form notes]]

====Quiz & question types====

*[[Development:Quiz UI redesign | Quiz UI redesign]]
*[[Development:Administration page for question types|Administration page for question types]]
*[[Development:Plan_to_Improve_Flexibility_of_Question_Category_Sharing_and_Permissions|Plans for enhancing the question bank]] - in Moodle 1.9
*[[Development:Email notification when a quiz is submitted|Email notification when a quiz is submitted]] - in Moodle 1.9
*[[Development:Plans for enhancing import/export in questiontype plugins]] - in Moodle 1.9
*[[Development:quiz_navigation | Quiz navigation]]
*[[Development:Open_protocol_for_accessing_question_engines|Open protocol for accessing question engines]]
*[[Development:Quiz report enhancements|Quiz report enhancements]]
*[[Development:Flagging questions during a quiz attempt|Flagging questions during a quiz attempt]]

====Other====

*[[Quiz and quesions community testing day]]

[[Category:Developer]]

Development:Developer notes

2010-09-12T20:31:47Z

Oasychev: /* Other */

'''Note:''' New developer documentation pages should be added to the ''Development namespace'' by typing <code>Development:</code> before the new page name i.e. <code><nowiki>[[Development:New page name]]</nowiki></code>.

This area is for developers to work on various bits of code and documentation as necessary. Once material has matured it should be linked to from the main [[Development:Developer documentation|Developer documentation]] page.

==Core code==

*[[Other lang issues|Language issues]]
*[[Datalib Notes]]
*[[Application/session variables]]
*[[Filters schema]]
*[[Filterall support]]
*[[Groups documentation for module developers]]
*[[Development:Plan to improve ability to delegate administrator tasks to course category level|Plan to improve ability to delegate administrator tasks to course category level]]
*[[Development:Stealth mode and nested activities|Stealth mode and nested activities]]
*[[Development:Enrolment_plugins_2.0|How enrolments should work in Moodle 2.0]]
*[[Development:Redesigning the override roles page|Redesigning the override roles page]]

===Gradebook===

*[[Development:Gradebook_improvements|Gradebook improvements]] - ideas from Petr.
*[[Development:Tim's_Gradebook_thoughts|Tim's Gradebook thoughts]]

==Modules and other recognised plugin types==

===Lesson===

*[[Adding_question_types_to_lesson|Adding question types to lesson module]]
*[[Development:New lesson navigation | New lesson navigation]]
*[[Development:Adding blocks to lesson | Adding blocks to lesson]]

===Quiz & question types===

* [[Development:File storage conversion Quiz and Questions|File storage conversion Quiz and Questions]] - notes for MDL-16094.
* [[Development:How the quiz navigation should work in Moodle 2.0|How the quiz navigation should work in Moodle 2.0]] - MDL-20276.
* [[Development:Moodle 2.0 question bank improvements|Moodle 2.0 question bank improvements]] - including question tagging and improved searchability.
* [[Development:Question_Engine_2|Proposal to change the Moodle Question Engine]] This supersedes
** [[Development:Plans for adaptive mode|Plans for adaptive mode]]
** [[Development:Implementation of true negative marks in MC-type questions|Implementation of true negative marks in MC-type questions]]
* [[Calculated question development]]
* [[Numerical question units and intervals]]
* [[Development:Categories editing interface improvment|Improvment of editing interface for category list]]
* [[Development:Future question bank/sharing/versioning requirements|Future question bank/sharing/versioning requirements]]
* [[Development:States of a quiz attempt]]
* [[Development:Optional checkbox "This is all my own work" before submitting a quiz]]

===Other activity modules===

*[[Forum development|Forum functional upgrade]]
*[[Wiki development|Wiki module development]]
*[[Development:Assignment development|New assignment-replacement module]]

===Gradebook Plugins===

*[[Development:External Database Plugin]]

===Other===

*[[Blogs and forums|Blogs, forums and the nature of discussion]]
*[[Conditional activities]]
*[[Improved Payment Plugin]]
*[[Development:Moodle-specific customisations to the HTML editor]]
*[[Development:Linked activities|Linked activities]]
*[[Development:Moodle Automatic Regression Test and Inspection Nit-picker]]
*[[Development: VSTU projects|Projects developed in Volgograd State Technical University]] becomes to many to simple list them on that page

== Markup & Theming ==
* [[Moodle CSS System]], idea from forum discussion on [http://moodle.org/mod/forum/discuss.php?d=126009 Object Oriented CSS]

==Other==

*[[MoodleDocs development]]
*[[Usability]]
*[[Document Management API]]
*[[wikindx|Possible integration of WIKINDX with Moodle]]
*[[Development:Snapshot - flat HTML export of complete course]]
*[[Development:Offline Moodle | Development:Offline Moodle - A Moodle that runs on a mobile device with the internet]]
*[[Development:A standard set of fixtures for unit tests?|A standard set of fixtures for unit tests?]]

==Archive: past proposals==

===Things that got implemented===

====Core code====

*[[Development:Ajax user selector|Ajax user selector]]
*[[Roles]] - in Moodle 1.7
*[[Moodle forms library]] - in Moodle 1.8
**[[Martin form notes]]

====Quiz & question types====

*[[Development:Quiz UI redesign | Quiz UI redesign]]
*[[Development:Administration page for question types|Administration page for question types]]
*[[Development:Plan_to_Improve_Flexibility_of_Question_Category_Sharing_and_Permissions|Plans for enhancing the question bank]] - in Moodle 1.9
*[[Development:Email notification when a quiz is submitted|Email notification when a quiz is submitted]] - in Moodle 1.9
*[[Development:Plans for enhancing import/export in questiontype plugins]] - in Moodle 1.9
*[[Development:quiz_navigation | Quiz navigation]]
*[[Development:Open_protocol_for_accessing_question_engines|Open protocol for accessing question engines]]
*[[Development:Quiz report enhancements|Quiz report enhancements]]
*[[Development:Flagging questions during a quiz attempt|Flagging questions during a quiz attempt]]

====Other====

*[[Quiz and quesions community testing day]]

[[Category:Developer]]

Development:Auto-feedback shortanswer question

2009-12-17T09:31:19Z

Oasychev: /* Examples of error reporting */

==Goal==
Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student answer and automatically generate feedback messages describing errors, which could be useful to the student without revealing correct answer (if necessary).

Such question is very useful in adaptive mode (and in non-adaptive mode too for courses with minimal teacher involvement) whenever you try to teach some language (eithern natural or artificial). If someone knows about works or papers that trying to do similar things please let me know there or on page comments.

Question still will be based (at least from the beginning) on entering a number of correct answers.

Question will be able to handle correct answer with several identical words, but that is discouraged (unless absolutely necessary) beacuse it will lower accuracy of feedback.

==External specification draft==

===Creating a question===
Teacher input one or several correct answers (with possible feedback describing particular answer). These answers are tokenised (this process will be called '''scanning''' later) to break them down to smaller parts ('''lexems'''): words, numbers, separators, operators etc.
:Since I couldn't start this work from writing universal scanner similar to the flex etc, it would be good to have pluginable scanners for the first time (e.g. natural language scanner, C++ scanner etc).

Teacher than asked for a names for all lexems, that could be shown to the user without revealing correct answer. Examples of tokenised answer with named lexems:

'''Function header in C language''': void function(int abc, char def)
; void : type of returned value
; function : function name
; ( : bracket (or opening bracket for function arguments)
; int : first argument type
; abc : first argument name
; , : argument list separator
; char : second argument type
; def : second argument name
; ) : bracket (or closing bracket for function arguments)

'''English language sentence''': The cat ate the mouse.
; The : definite article
; cat : subject
; ate : verb
; the : definite article
; mouse : complement
; . : sentence ending point

:Could anyone write a natural language example please? I don't know well grammatical categories of English language in English to do so.

There will be probably some settings to determine how a grade should be calculated in case of errors, but they could be defined later.

===Types of errors to report===
# misspelled word (number, another complex lexem)
# missing separator
# invalid separator
# misplaced word (number, etc)
# missing word (number, etc)
# unwanted word (number, separator, etc)

===Examples of error reporting===
'''Correct answer''': void function(int abc, char def)

'''Student's response''': funcion (int, chardef)void

'''Feedback from the question''':

* please check function name, you are probably misspelled it
* first argument name is missing
* missing separator between second argument type and second argument name
* type of returned value is probably misplaced

'''Correct answer''': The cat ate the mouse.

'''Student's response''': The mouse eat a cat.

'''Feedback from the question''':
* complement misplaced
* verb is in wrong tense
* wrong article used before the subject
* subject misplaced

Development:Auto-feedback shortanswer question

2009-12-17T09:28:26Z

Oasychev: /* Creating a question */

Development:Auto-feedback shortanswer question

2009-12-15T12:44:35Z

Oasychev: /* Creating a question */

==Goal==
Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student answer and automatically generate feedback messages describing errors, which could be useful to the student without revealing correct answer (if necessary).

Such question is very useful in adaptive mode (and in non-adaptive mode too for courses with minimal teacher involvement) whenever you try to teach some language (eithern natural or artificial). If someone knows about works or papers that trying to do similar things please let me know there or on page comments.

Question still will be based (at least from the beginning) on entering a number of correct answers.

Question will be able to handle correct answer with several identical words, but that is discouraged (unless absolutely necessary) beacuse it will lower accuracy of feedback.

==External specification draft==

===Creating a question===
Teacher input one or several correct answers (with possible feedback describing particular answer). These answers are tokenised (this process will be called '''scanning''' later) to break them down to smaller parts ('''lexems'''): words, numbers, separators, operators etc.
:Since I couldn't start this work from writing universal scanner similar to the flex etc, it would be good to have pluginable scanners for the first time (e.g. natural language scanner, C++ scanner etc).

Teacher than asked for a names for all lexems, that could be shown to the user without revealing correct answer. Examples of tokenised answer with named lexems:

'''Function header in C language''': void function(int abc, char def)
; void : type of returned value
; function : function name
; ( : bracket (or opening bracket for function arguments)
; int : first argument type
; abc : first argument name
; , : argument list separator
; char : second argument type
; def : second argument name
; ) : bracket (or closing bracket for function arguments)

:Could anyone write a natural language example please? I don't know well grammatical categories of English language in English to do so.

There will be probably some settings to determine how a grade should be calculated in case of errors, but they could be defined later.

===Types of errors to report===
# misspelled word (number, another complex lexem)
# missing separator
# invalid separator
# misplaced word (number, etc)
# missing word (number, etc)
# unwanted word (number, separator, etc)

===Examples of error reporting===
'''Correct answer''': void function(int abc, char def)

'''Student's response''': funcion (int, chardef)void

'''Feedback from the question''':

* please check function name, you are probably misspelled it
* first argument name is missing
* missing separator between second argument type and second argument name
* type of returned value is probably misplaced

Development:Auto-feedback shortanswer question

2009-12-15T12:42:09Z

Oasychev: /* Examples of error reporting */

==Goal==
Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student answer and automatically generate feedback messages describing errors, which could be useful to the student without revealing correct answer (if necessary).

Such question is very useful in adaptive mode (and in non-adaptive mode too for courses with minimal teacher involvement) whenever you try to teach some language (eithern natural or artificial). If someone knows about works or papers that trying to do similar things please let me know there or on page comments.

Question still will be based (at least from the beginning) on entering a number of correct answers.

Question will be able to handle correct answer with several identical words, but that is discouraged (unless absolutely necessary) beacuse it will lower accuracy of feedback.

==External specification draft==

===Creating a question===
Teacher input one or several correct answers (with possible feedback describing particular answer). These answers are tokenised (this process will be called '''scanning''' later) to break them down to smaller parts ('''lexems'''): words, numbers, separators, operators etc.
:Since I couldn't start this work from writing universal scanner similar to the flex etc, it would be good to have pluginable scanners for the first time (e.g. natural language scanner, C++ scanner etc).

Teacher than asked for a names for all lexems, that could be shown to the user without revealing correct answer. Examples of tokenised answer with named lexems:

'''Function header in C language''': void function(int abc, char def)
* void - type of returned value
* function - function name
* ( - bracket (or opening bracket for function arguments)
* int - type of the first argument
* abc - name of the first argument
* , - argument list separator
* char - type of the second argument
* def - name of the second argument
* ) - bracket (or closing bracket for function arguments)

:Could anyone write a natural language example please? I don't know well grammatical categories of English language in English to do so.

There will be probably some settings to determine how a grade should be calculated in case of errors, but they could be defined later.

===Types of errors to report===
# misspelled word (number, another complex lexem)
# missing separator
# invalid separator
# misplaced word (number, etc)
# missing word (number, etc)
# unwanted word (number, separator, etc)

===Examples of error reporting===
'''Correct answer''': void function(int abc, char def)

'''Student's response''': funcion (int, chardef)void

'''Feedback from the question''':

* please check function name, you are probably misspelled it
* first argument name is missing
* missing separator between second argument type and second argument name
* type of returned value is probably misplaced

Development:Auto-feedback shortanswer question

2009-12-15T12:34:56Z

Oasychev: /* Types of errors to report */

==Goal==
Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student answer and automatically generate feedback messages describing errors, which could be useful to the student without revealing correct answer (if necessary).

Such question is very useful in adaptive mode (and in non-adaptive mode too for courses with minimal teacher involvement) whenever you try to teach some language (eithern natural or artificial). If someone knows about works or papers that trying to do similar things please let me know there or on page comments.

Question still will be based (at least from the beginning) on entering a number of correct answers.

Question will be able to handle correct answer with several identical words, but that is discouraged (unless absolutely necessary) beacuse it will lower accuracy of feedback.

==External specification draft==

===Creating a question===
Teacher input one or several correct answers (with possible feedback describing particular answer). These answers are tokenised (this process will be called '''scanning''' later) to break them down to smaller parts ('''lexems'''): words, numbers, separators, operators etc.
:Since I couldn't start this work from writing universal scanner similar to the flex etc, it would be good to have pluginable scanners for the first time (e.g. natural language scanner, C++ scanner etc).

Teacher than asked for a names for all lexems, that could be shown to the user without revealing correct answer. Examples of tokenised answer with named lexems:

'''Function header in C language''': void function(int abc, char def)
* void - type of returned value
* function - function name
* ( - bracket (or opening bracket for function arguments)
* int - type of the first argument
* abc - name of the first argument
* , - argument list separator
* char - type of the second argument
* def - name of the second argument
* ) - bracket (or closing bracket for function arguments)

:Could anyone write a natural language example please? I don't know well grammatical categories of English language in English to do so.

There will be probably some settings to determine how a grade should be calculated in case of errors, but they could be defined later.

===Types of errors to report===
# misspelled word (number, another complex lexem)
# missing separator
# invalid separator
# misplaced word (number, etc)
# missing word (number, etc)
# unwanted word (number, separator, etc)

===Examples of error reporting===

Development:Auto-feedback shortanswer question

2009-12-15T12:31:19Z

Oasychev: New page: ==Goal== Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student ...

==Goal==
Develop a question type, that was similar to shortanswer (except that no initial wildcard support is planned, thought it can be added later) which will be able to analyze student answer and automatically generate feedback messages describing errors, which could be useful to the student without revealing correct answer (if necessary).

Such question is very useful in adaptive mode (and in non-adaptive mode too for courses with minimal teacher involvement) whenever you try to teach some language (eithern natural or artificial). If someone knows about works or papers that trying to do similar things please let me know there or on page comments.

Question still will be based (at least from the beginning) on entering a number of correct answers.

Question will be able to handle correct answer with several identical words, but that is discouraged (unless absolutely necessary) beacuse it will lower accuracy of feedback.

==External specification draft==

===Creating a question===
Teacher input one or several correct answers (with possible feedback describing particular answer). These answers are tokenised (this process will be called '''scanning''' later) to break them down to smaller parts ('''lexems'''): words, numbers, separators, operators etc.
:Since I couldn't start this work from writing universal scanner similar to the flex etc, it would be good to have pluginable scanners for the first time (e.g. natural language scanner, C++ scanner etc).

Teacher than asked for a names for all lexems, that could be shown to the user without revealing correct answer. Examples of tokenised answer with named lexems:

'''Function header in C language''': void function(int abc, char def)
* void - type of returned value
* function - function name
* ( - bracket (or opening bracket for function arguments)
* int - type of the first argument
* abc - name of the first argument
* , - argument list separator
* char - type of the second argument
* def - name of the second argument
* ) - bracket (or closing bracket for function arguments)

:Could anyone write a natural language example please? I don't know well grammatical categories of English language in English to do so.

There will be probably some settings to determine how a grade should be calculated in case of errors, but they could be defined later.

===Types of errors to report===

===Examples of error reporting===