qtype_numerical_answer_processor Class Reference

This class processes numbers with units. More...

Public Member Functions
	__construct ($units, $unitsbefore=false, $decsep=null, $thousandssep=null)
	add_unit ($answer, $unit=null)
	apply_units ($response, $separateunit=null)
	Takes a number in almost any localised form, and possibly with a unit after it. More...
	are_units_before ()
	Whether the units go before or after the number. More...
	contains_thousands_seaparator ($value)
	get_default_unit ()
	get_point ()
	get_separator ()
	get_unit_options ()
	Get the units as an array suitably for passing to html_writer::select. More...
	is_known_unit ($unit)
	Is this unit recognised. More...
	set_characters ($decsep, $thousandssep)
	Set the decimal point and thousands separator character that should be used. More...

Protected Member Functions
	build_regex ()
	Create the regular expression that parse_response() requires. More...
	parse_response ($response)
	This method can be used for more locale-strict parsing of repsonses. More...

Protected Attributes
string	$decsep
	character used as decimal point.
	$regex = null
string	$thousandssep
	character used as thousands separator.
array	$units
	unit name => multiplier.
boolean	$unitsbefore
	whether the units come before or after the number.

Detailed Description

This class processes numbers with units.

Copyright

2010 The Open University

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Member Function Documentation

add_unit()

qtype_numerical_answer_processor::add_unit	(		$answer,
			$unit = null
	)

Parameters

string	$answer	a response.
string	$unit	a unit.

apply_units()

qtype_numerical_answer_processor::apply_units	(		$response,
			$separateunit = null
	)

Takes a number in almost any localised form, and possibly with a unit after it.

It separates off the unit, if present, and converts to the default unit, by using the given unit multiplier.

Parameters

string

$response

a value, optionally with a unit.

Return values

array(numeric,sting)

the value with the unit stripped, and normalised by the unit multiplier, if any, and the unit string, for reference.

are_units_before()

qtype_numerical_answer_processor::are_units_before

(

)

Whether the units go before or after the number.

Return values

true	= before, false = after.

build_regex()

qtype_numerical_answer_processor::build_regex ( )

protected

Create the regular expression that parse_response() requires.

Return values

string

contains_thousands_seaparator()

qtype_numerical_answer_processor::contains_thousands_seaparator

(

$value

)

Return values

bool	If the student's response contains a '.' or a ',' that matches the thousands separator in the current locale. In this case, the parsing in apply_unit can give a result that the student did not expect.

get_default_unit()

qtype_numerical_answer_processor::get_default_unit

(

)

Return values

string

the default unit.

get_point()

qtype_numerical_answer_processor::get_point

(

)

Return values

string

the decimal point character used.

get_separator()

qtype_numerical_answer_processor::get_separator

(

)

Return values

string

the thousands separator character used.

get_unit_options()

qtype_numerical_answer_processor::get_unit_options

(

)

Get the units as an array suitably for passing to html_writer::select.

Return values

array

of unit choices.

is_known_unit()

qtype_numerical_answer_processor::is_known_unit

(

$unit

)

Is this unit recognised.

Parameters

string

$unit

the unit

Return values

bool	whether this is a unit we recognise.

parse_response()

qtype_numerical_answer_processor::parse_response (   $response )

protected

This method can be used for more locale-strict parsing of repsonses.

At the moment we don't use it, and instead use the more lax parsing in apply_units. This is just a note that this funciton was used in the past, so if you are intersted, look through version control history.

Take a string which is a number with or without a decimal point and exponent, and possibly followed by one of the units, and split it into bits.

Parameters

string

$response

a value, optionally with a unit.

Return values

array

four strings (some of which may be blank) the digits before and after the decimal point, the exponent, and the unit. All four will be null if the response cannot be parsed.

set_characters()

qtype_numerical_answer_processor::set_characters	(		$decsep,
			$thousandssep
	)

Set the decimal point and thousands separator character that should be used.

Parameters

string	$decsep
string	$thousandssep

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The documentation for this class was generated from the following file:

• question/type/numerical/questiontype.php