This version fixes issues with obsolete javascript code.

Perl-compatible regular expression question

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, FA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. Explaining graph (authoring tool) - Vladimir Ivanov.


4. Syntax tree (authoring tool) - Grigory Terekhov.


5. Regex description (authoring tool) - Dmitriy Pahomov.


6. Assertion support - Elena Lepilkina.


7. Typo detection - Artem Prokudin

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
FA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.
Be sure to use Graphviz 2.36 or newer (earlier versions had a bug in svg output which led to incorrect pictures).

==========
3. Hinting

FA matching engine support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose FA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Regex constructor

Regex constructor help you with regular expression development. There are several tools in it. For now they are concentrated on the
describing you regular expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

Perl-compatible regular expression question

The major new feature of this release is the support for detecting typos in students' responses.

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, FA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. Explaining graph (authoring tool) - Vladimir Ivanov.


4. Syntax tree (authoring tool) - Grigory Terekhov.


5. Regex description (authoring tool) - Dmitriy Pahomov.


6. Assertion support - Elena Lepilkina.


7. Typo detection support - Prokudin Artem

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
FA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.
Be sure to use Graphviz 2.36 or newer (earlier versions had a bug in svg output which led to incorrect pictures).

==========
3. Hinting

FA matching engine support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose FA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Regex constructor

Regex constructor help you with regular expression development. There are several tools in it. For now they are concentrated on the
describing you regular expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

Perl-compatible regular expression question

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, FA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. Explaining graph (authoring tool) - Vladimir Ivanov.


4. Syntax tree (authoring tool) - Grigory Terekhov.


5. Regex description (authoring tool) - Dmitriy Pahomov.


6. Assertion support - Elena Lepilkina.

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
FA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.
Be sure to use Graphviz 2.36 or newer (earlier versions had a bug in svg output which led to incorrect pictures).

==========
3. Hinting

FA matching engine support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose FA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Regex constructor

Regex constructor help you with regular expression development. There are several tools in it. For now they are concentrated on the
describing you regular expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

This techincal release aimed at PHP 7 support

Perl-compatible regular expression question

WARNING: this version may not work on PHP 5.6 due to bug in the PHP. The bug was fixed, but fix would be available with PHP 5.7

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, FA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. Explaining graph (authoring tool) - Vladimir Ivanov.


4. Syntax tree (authoring tool) - Grigory Terekhov.


5. Regex description (authoring tool) - Dmitriy Pahomov.


6. Assertion support - Elena Lepilkina

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
FA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.
Be sure to use Graphviz 2.36 or newer (earlier versions had a bug in svg output which led to incorrect pictures).

==========
3. Hinting

FA matching engine support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions, conditional subexpressions, recursion etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose FA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Regex constructor

Regex constructor help you with regular expression development. There are several tools in it. For now they are concentrated on the
describing you regular expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

This is a technical release to adopt question for Moodle 2.7

Perl-compatible regular expression question

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, FA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. Explaining graph (authoring tool) - Vladimir Ivanov.


4. Syntax tree (authoring tool) - Grigory Terekhov.


5. Regex description (authoring tool) - Dmitriy Pahomov.

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
FA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.
Be sure to use Graphviz 2.36 or newer (earlier versions had a bug in svg output which led to incorrect pictures).

==========
3. Hinting

FA matching engine support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions, conditional subexpressions, recursion etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose FA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Regex constructor

Regex constructor help you with regular expression development. There are several tools in it. For now they are concentrated on the
describing you regular expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

Perl-compatible regular expression question

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, NFA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. DFA regex matching engine (deprecated for now) - Dmitriy Kolesov.


4. Explaining graph (authoring tool) - Vladimir Ivanov.


5. Syntax tree (authoring tool) - Grigory Terekhov.


6. Regex description (authoring tool) - Dmitriy Pahomov.

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
NFA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.

==========
3. Hinting

DFA and NFA matching engines support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions, conditional subexpressions, recursion etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose NFA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Authoring tools

Authoring tools help you with regular expression development. For now they are concentrated on the describing you regular
expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

Perl-compatible regular expression question

Authors:

1. Idea, design, question type and behaviours code, hinting, error reporting, regular expression testing (authoring tool) - Oleg Sychev.


2. Regex parsing, NFA regex matching engine, matchers testing, backup&restore, unicode support, selection in regex text (in authoring tools) - Valeriy Streltsov.


3. DFA regex matching engine (deprecated for now) - Dmitriy Kolesov.


4. Explaining graph (authoring tool) - Vladimir Ivanov.


5. Syntax tree (authoring tool) - Grigory Terekhov.


6. Regex description (authoring tool) - Dmitriy Pahomov.

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question;


• Bondarenko Vitaly - for conversion of a vast set of regular expression matching tests from PCRE library.

==============

1. Description
   ==============
   The question was primarily intended to allow the usage of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive and interactive
behaviours if the student is stuck, which can be useful in training quizzes.

To use hinting you don't need to know anything about regular expressions. Choosing Moodle Shortanswer notation allows
you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
NFA engine is preferable for such questions for now.

===============
2. Installation

To work with hinting, Preg question type needs 2 behaviours: adaptivehints and adaptivehintsnopenalties.
They all need to be installed in order for question to work. You can download the question type and behaviours
in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow them to be downloaded together),
you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type folder of Moodle installation.
"adaptivehints", "interactivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of your teachers would use it, though you can choose engine in every question.
See the "Matching engines" section for more information.

In order to get Authoring tools to work, you should also install Graphviz package and make it accessible from Moodle, using the admin setting
"Path to Dot" at Administration > Server > System Paths. It is necessary for drawing Syntax Tree and Explaining Graph for regular expression.
Graphviz is a well-known and respected open source package for drawing graphs and should not cause any trouble to you server.

==========
3. Hinting

DFA and NFA matching engines support hinting for partial matching. If there is no full match in the response,
question chooses the partial match that has less characters to complete matching. It could also show
a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

===================
4. Matching engines

There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
choosing default engine, that could be set on the question type settings page.

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions, conditional subexpressions, recursion etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose NFA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

==================
5. Authoring tools

Authoring tools help you with regular expression development. For now they are concentrated on the describing you regular
expression in different ways.

Syntax tree shows you the internal structure of expression - what is inside what. If you understand regular expressions throught operators
and operands, it can be of a great help to you. If not, it can help you determine if repeating or alternative applied to the correct parts
of the expression, do you need to use parentheses and where they should be placed.

Explaining graph shows you graphically how expression works: its nodes are characters or character sequences; concatenation, alternation and
simple assertions are shown by edges, while rectangles show you repetition and subpattern capturing.

Description is a natural language sentence, generated from regular expression, which explains you how your expression will work.

Testing tool allows you to see how you regexes match different strings. It expected to be much more convenient than question previewing.
Entered test strings will be saved in database with the question for future use.

For better understanding of how regex parts affect the entire picture, you can select a regex part to be highlighted in the syntax tree,
explaining graph and description tools. Testing tool will show you parts of strings, matched with given selection.

====================================
6. Bugs, suggestions and giving back

Please report bugs at GoogleCode tracker (set Component-Preg label) - this is the preferable way - or at Moodle tracker.
Google Code tracker can be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
You may also post suggestions of how to develop question type in the future, but please accompany them with information of
who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary mean money or tough programming.

You could publish a paper or thesis about using this question type and send me a reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and its usage with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "tests" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.

This version should be stable enought for production in existing features of Preg question, but is BETA quality in major new feature - Authoring Tools.

If you are forced to upgrade and use Preg question right now use it. I plan a STABLE release in early September.

Small buggix to Preg 2.3.1

This is bugfix and small improvments release of Preg 2.3. Use with corresponding behaviour versions only,

If you use Preg 2.3, it is strongly recommended to upgrade to this version.

Changes:

• standard Moodle text hints now supported in adapative behaviour along with special Preg hints;


• default language setting should finally work;


• fixed syntax error in lib.php, which could interfere with cron script execution;


• several fixes in NFA engine, improving already good whole match possibilities for several corner cases.

Perl-compatible regular expression question

Authors:

1. Idea, design, question type code, error reporting, hinting - Oleg Sychev


2. Parsing regular expression, DFA regular expression matching engine - Dmitriy Kolesov


3. NFA regular expression matching engine, backreferences, matchers cross-testing, Unicode support - Valeriy Streltsov

Thanks going to:

• Joseph Rezeau - for been devoted tester of preg question type in several releases;


• Tim Hunt - for his polite and useful answers and commentaries that helped writing this question.

1. Description
   The question was primarily intended to allow the use of php perl-compatible regular expressions in short answer
   questions. It supports full regular expression syntax and can be used with expressions of any complexity
   that php preg extension can handle. Regular expressions can be used to specify wide array of patterns for student
   answer to match. You can find some links to the descriptions of regular expression syntax in the question docs.

Preg question is also able to hint next character or lexem for a specified penalty in adaptive behaviour if the student is stuck.

You could use hinting without the need to know anything about regular expressions. Choosing Moodle Shortanswer
notation allows you to just copy answers from shortanswer question and have hinting capabilities. '*' wildcard is supported.
NFA engine is preferable for such questions for now.

2. Installation
   To work with hinting, Preg question type needs to behaviours: adaptivehints and adaptivehintsnopenalties.
   They all need to be installed in order for question to work. You could download question type and behaviours
   in one archive (from GoogleCode or GitHub) or separately.

If you downloaded one archive, unpacking it you should found "question" and "blocks" folders. Copy them in the main
directory of Moodle installation (the one containing config.php) - it will install everything in the correct places.

If you downloaded all parts separately (for example because Moodle Plugins Directory don't allow
them to be downloaded together), you should get 5 archives. Place "preg" and "poasquestion" folders in the question/type
folder of Moodle installation. "adaptivehints" and "adaptivehintsnopenalties" should be placed in question/behaviour folder.
"formal_langs" should be placed in the blocks folder.

After having files in place login as administrator and go to the notifications page.

Pay heed to the default matching engine setting. Most of you teachers would use it, thought you could choose engine in every question.
See "Matching engines" section for more information.

3. 
   

   Hinting
   DFA and NFA matching engines support hinting for partial matching. If there is no full match in the response,
   question chooses the partial match that has less characters to complete matching. It could also show
   a next character (or lexem) that leads to the shortest path to complete matching as a hint (with adding hint penalty)
   when using adaptive behaviour. Only answers with grade greater or equal hint grade border are used in hinting.

   
   


4. 
   

   Matching engines
   There is no 'best' matching enginge, so you could choose best fit for every question. Start by analyzing you needs and
   choosing default engine, that could be set on the question type settings page.

   
   

If you primary need is to use very complex regular expressions, than "PHP preg extension" is you most likely choice.
By "very complex" we understand regular expression using complex assertions, conditional subpatterns, recursion etc.

If you regular expressions are not that hardcore, but you want to make heavy use of hinting facility, choose NFA engine instead.

Then just experiment. If some engine don't allow you to do something you need (you get messages that something is unsupported, or
regular expression is too complex or hinting is inactive etc) or just have bug in you particular regular expression - try another one.

5. Bugs, suggestions and giving back
   Please report bugs in GoogleCode tracker (set Component-Preg label) - this is preferable way - or Moodle tracker.
   Google Code tracker could be found there: http://code.google.com/p/oasychev-moodle-plugins/issues/list
   You also may post a suggestions of how to develop question type in the future, but please accompany them with information of
   who are you, how you are using question type and how you intend to use enchancements you suggest pedagogically.

If you like the project, please consider helping it too. That doesn't necessary means money or tough programming.

You could publish a paper or thesis about using this question type and send me reference I could quote to
improve rating of this project. If you could publish a scientific paper on this question and it's use with
me as co-author this would help much more, please inform me immediately if you choose to do so.

You could also help by testing - either manual or unit-testing. Unit-testing of regular expressions
is not that hard - look for cross-test files in "simpletest" subfolder of "preg" folder for examples and feel free to ask me questions
about them. You need not be much of a programmer to write them at all - you only need to know regular expressions.