qtype_calculated_variable_substituter Class Reference

Public Member Functions
	__construct (array $values, $decimalpoint)
	format_float ($x, $length=null, $format=null)
	get_values ()
	calculate ($expression)
	replace_expressions_in_text ($text, $length=null, $format=null)
	get_formula_errors ($formula)
Protected Member Functions
	calculate_raw ($expression)
	substitute_values_for_eval ($expression)
	substitute_values_pretty ($text)
Protected Attributes
	$values
	$decimalpoint
	$search
	$safevalue
	$prettyvalue

---

Detailed Description

This class holds the current values of all the variables used by a calculated question.

It can compute formulae using those values, and can substitute equations embedded in text.

Copyright:

2011 The Open University http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Definition at line 261 of file question.php.

---

Constructor & Destructor Documentation

__construct	(	array $	values,
		$	decimalpoint
	)

Constructor

Parameters:

array

$values

variable name => value.

Definition at line 287 of file question.php.

Here is the call graph for this function:

---

Member Function Documentation

calculate

(

$

expression

)

Evaluate an expression using the variable values.

Parameters:

string

$expression

the expression. A PHP expression with placeholders like {a} for where the variables need to go.

Returns:

float the computed result.

Definition at line 343 of file question.php.

Here is the call graph for this function:

calculate_raw

(

$

expression

)

[protected]

Evaluate an expression after the variable values have been substituted.

Parameters:

string

$expression

the expression. A PHP expression with placeholders like {a} for where the variables need to go.

Returns:

float the computed result.

Definition at line 353 of file question.php.

Here is the caller graph for this function:

format_float	(	$	x,
		$	length = null,
		$	format = null
	)

Display a float properly formatted with a certain number of decimal places.

Parameters:

number	$x	the number to format
int	$length	restrict to this many decimal places or significant figures. If null, the number is not rounded.
	int	format 1 => decimalformat, 2 => significantfigures.

Returns:

string formtted number.

Definition at line 316 of file question.php.

Here is the caller graph for this function:

get_formula_errors

(

$

formula

)

Return an array describing any problems there are with an expression. Returns false if the expression is fine.

Parameters:

string

$formula

an expression.

Returns:

array|false list of problems, or false if the exression is OK.

Definition at line 405 of file question.php.

get_values

(

)

Return an array of the variables and their values.

Returns:

array name => value.

Definition at line 333 of file question.php.

replace_expressions_in_text	(	$	text,
		$	length = null,
		$	format = null
	)

Replace any embedded variables (like {a}) or formulae (like {={a} + {b}}) in some text with the corresponding values.

Parameters:

string

$text

the text to process.

Returns:

string the text with values substituted.

Definition at line 390 of file question.php.

Here is the call graph for this function:

substitute_values_for_eval

(

$

expression

)

[protected]

Substitute variable placehodlers like {a} with their value wrapped in ().

Parameters:

string

$expression

the expression. A PHP expression with placeholders like {a} for where the variables need to go.

Returns:

string the expression with each placeholder replaced by the corresponding value.

Definition at line 368 of file question.php.

Here is the caller graph for this function:

substitute_values_pretty

(

$

text

)

[protected]

Substitute variable placehodlers like {a} with their value without wrapping the value in anything.

Parameters:

string

$text

some content with placeholders like {a} for where the variables need to go.

Returns:

string the expression with each placeholder replaced by the corresponding value.

Definition at line 380 of file question.php.

Here is the caller graph for this function:

---

Field Documentation

$decimalpoint [protected]

Definition at line 266 of file question.php.

$prettyvalue [protected]

Definition at line 281 of file question.php.

$safevalue [protected]

Definition at line 275 of file question.php.

$search [protected]

Definition at line 269 of file question.php.

$values [protected]

Definition at line 263 of file question.php.

---

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

• C:/xampp/htdocs/moodle/question/type/calculated/question.php