This file is part of ILIAS, a powerful learning management system published by ILIAS open source e-Learning e.V. More...

Collaboration diagram for ilDclExpressionParser:

Public Member Functions
	__construct (string $expression, ilDclBaseRecordModel $record, ilDclBaseFieldModel $field)

	parse ()
	Parse expression and return result. More...

Static Public Member Functions
static	getOperators ()

static	getFunctions ()

Data Fields
const	N_DECIMALS = 1

const	SCIENTIFIC_NOTATION_UPPER = 1000000000000

const	SCIENTIFIC_NOTATION_LOWER = 0.000000001

Protected Member Functions
	formatScientific ($value)

	isMathToken (string $token)
	Check if a given token is a math expression. More...

	calculateFunctions (string $token)
	Execute any math functions inside a token. More...

	getFunctionArgs (int $index, array $data)
	Helper method to return the function and its arguments from a preg_replace_all $result array. More...

	substituteFieldValues (array $tokens)
	Given an array of tokens, replace each token that is a placeholder (e.g. More...

	parseMath (array $tokens)
	Parse a math expression. More...

	calculateFunction (string $function, array $args=array())
	Calculate a function with its arguments. More...

	calculate (string $operator, $left, $right)

Protected Attributes
ilDclBaseRecordModel	$record

ilDclBaseFieldModel	$field

string	$expression

Static Protected Attributes
static array	$operators

static array	$cache_tokens = array()

static array	$cache_fields = array()

static array	$cache_math_tokens = array()

static array	$cache_math_function_tokens = array()

static array	$functions

Detailed Description

This file is part of ILIAS, a powerful learning management system published by ILIAS open source e-Learning e.V.

ILIAS is licensed with the GPL-3.0, see https://www.gnu.org/licenses/gpl-3.0.en.html You should have received a copy of said license along with the source code, too.

If this is not the case or you just want to try ILIAS, you'll find us at: https://www.ilias.de https://github.com/ILIAS-eLearning

Definition at line 19 of file class.ilDclExpressionParser.php.

Constructor & Destructor Documentation

◆ __construct()

ilDclExpressionParser::__construct	(	string	$expression,
		ilDclBaseRecordModel	$record,
		ilDclBaseFieldModel	$field
	)

Definition at line 48 of file class.ilDclExpressionParser.php.

    {
        $this->expression = $expression;
        $this->record = $record;
        $this->field = $field;
    }

References $expression, $field, and $record.

Member Function Documentation

◆ calculate()

ilDclExpressionParser::calculate	(	string	$operator,
			$left,
			$right
	)

protected

Parameters

string	$operator
float \| int	$left
float \| int	$right

Returns: float|int

Exceptions

ilException

Definition at line 355 of file class.ilDclExpressionParser.php.

    {
        switch ($operator) {
            case '+':
                $result = $left + $right;
                break;
            case '-':
                $result = $left - $right;
                break;
            case '*':
                $result = $left * $right;
                break;
            case '/':
                $result = ($right == 0) ? 0 : $left / $right;
                break;
            case '^':
                $result = pow($left, $right);
                break;
            default:
                throw new ilException("Unrecognized operator '$operator'");
        }
 
        return $result;
    }

Referenced by parseMath().

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◆ calculateFunction()

ilDclExpressionParser::calculateFunction	(	string	$function,
		array	$args = `array()`
	)

protected

Calculate a function with its arguments.

Returns: float|int|number

Exceptions

ilException

Definition at line 330 of file class.ilDclExpressionParser.php.

    {
        switch ($function) {
            case 'AVERAGE':
                $count = count($args);
 
                return ($count) ? array_sum($args) / $count : 0;
            case 'SUM':
                return array_sum($args);
            case 'MIN':
                return min($args);
            case 'MAX':
                return max($args);
            default:
                throw new ilException("Unrecognized function '$function'");
        }
    }

Referenced by calculateFunctions().

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◆ calculateFunctions()

ilDclExpressionParser::calculateFunctions ( string $token )

protected

Execute any math functions inside a token.

Definition at line 148 of file class.ilDclExpressionParser.php.

                                                        : string
    {
        if (isset(self::$cache_math_function_tokens[$this->field->getId()][$token])) {
            $result = self::$cache_math_function_tokens[$this->field->getId()][$token];
            if ($result === false) {
                return $token;
            }
        } else {
            $pattern = '#';
            foreach (self::getFunctions() as $function) {
                $pattern .= "($function)\\(([^)]*)\\)|";
            }
            if (!preg_match_all(rtrim($pattern, '|') . '#', $token, $result)) {
                // No functions found inside token, just return token again
                self::$cache_math_function_tokens[$this->field->getId()][$token] = false;
 
                return $token;
            }
        }
        // Function found inside token, calculate!
        foreach ($result[0] as $k => $to_replace) {
            $function_args = $this->getFunctionArgs($k, $result);
            $function = $function_args['function'];
            $args = $this->substituteFieldValues($function_args['args']);
            $token = str_replace($to_replace, $this->calculateFunction($function, $args), $token);
        }
 
        return $token;
    }

References $token, calculateFunction(), getFunctionArgs(), and substituteFieldValues().

Referenced by parse().

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◆ formatScientific()

ilDclExpressionParser::formatScientific ( $value )

protected

Parameters

float | int $value

Returns: string|int

Definition at line 101 of file class.ilDclExpressionParser.php.

    {
        if (abs($value) >= self::SCIENTIFIC_NOTATION_UPPER) {
            return sprintf("%e", $value);
        }
        if (abs($value) <= self::SCIENTIFIC_NOTATION_LOWER && $value != 0) {
            return sprintf("%e", $value);
        }
        return $value;
    }

Referenced by parse().

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◆ getFunctionArgs()

ilDclExpressionParser::getFunctionArgs	(	int	$index,
		array	$data
	)

protected

Helper method to return the function and its arguments from a preg_replace_all $result array.

Definition at line 181 of file class.ilDclExpressionParser.php.

                                                               : array
    {
        $return = array(
            'function' => '',
            'args' => array(),
        );
        for ($i = 1; $i < count($data); $i++) {
            $_data = $data[$i];
            if ($_data[$index]) {
                $function = $_data[$index];
                $args = explode(';', $data[$i + 1][$index]);
                $return['function'] = $function;
                $return['args'] = $args;
                break;
            }
        }
 
        return $return;
    }

References $data, $i, and $index.

Referenced by calculateFunctions().

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◆ getFunctions()

static ilDclExpressionParser::getFunctions ( )

static

Definition at line 117 of file class.ilDclExpressionParser.php.

                                         : array
    {
        return self::$functions;
    }

References $functions.

Referenced by ilDclFormulaFieldRepresentation\buildFieldCreationInput(), ilDclTable\getFieldsForFormula(), and isMathToken().

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◆ getOperators()

static ilDclExpressionParser::getOperators ( )

static

Definition at line 112 of file class.ilDclExpressionParser.php.

                                         : array
    {
        return self::$operators;
    }

References $operators.

Referenced by ilDclFormulaFieldRepresentation\buildFieldCreationInput(), ilDclTable\getFieldsForFormula(), and ilDclTokenizer\getMathTokens().

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◆ isMathToken()

ilDclExpressionParser::isMathToken ( string $token )

protected

Check if a given token is a math expression.

Definition at line 125 of file class.ilDclExpressionParser.php.

                                                 : bool
    {
        if (isset(self::$cache_math_tokens[$this->field->getId()][$token])) {
            return self::$cache_math_tokens[$this->field->getId()][$token];
        } else {
            if (strpos($token, '"') === 0) {
                return false;
            }
            $operators = array_keys(self::getOperators());
            $functions = self::getFunctions();
            $result = (bool) preg_match(
                '#(\\' . implode("|\\", $operators) . '|' . implode('|', $functions) . ')#',
                $token
            );
            self::$cache_math_tokens[$this->field->getId()][$token] = $result;
 
            return $result;
        }
    }

References $functions, $operators, $token, and getFunctions().

Referenced by parse().

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◆ parse()

ilDclExpressionParser::parse ( )

Parse expression and return result.

This method loops the tokens and checks if Token is of type string or math. Concatenates results to produce resulting string of parsed expression.

Exceptions

ilException

Definition at line 61 of file class.ilDclExpressionParser.php.

                           : string
    {
        if (isset(self::$cache_tokens[$this->field->getId()])) {
            $tokens = self::$cache_tokens[$this->field->getId()];
        } else {
            $tokens = ilDclTokenizer::getTokens($this->expression);
            self::$cache_tokens[$this->field->getId()] = $tokens;
        }
        $parsed = '';
        foreach ($tokens as $token) {
            if (empty($token)) {
                continue;
            }
            if ($this->isMathToken($token)) {
                $token = $this->calculateFunctions($token);
                $math_tokens = ilDclTokenizer::getMathTokens($token);
                $value = $this->parseMath($this->substituteFieldValues($math_tokens));
 
                $value = $this->formatScientific($value);
 
                $parsed .= $value;
            } else {
                // Token is a string, either a field placeholder [[Field name]] or a string starting with "
                if (strpos($token, '"') === 0) {
                    $parsed .= strip_tags(trim($token, '"'));
                } elseif (strpos($token, '[[') === 0) {
                    $parsed .= trim(strip_tags($this->substituteFieldValue($token)));
                } else {
                    throw new ilException("Unrecognized string token: '$token'");
                }
            }
        }
 
        return $parsed;
    }

References $token, calculateFunctions(), formatScientific(), ilDclTokenizer\getMathTokens(), ilDclTokenizer\getTokens(), isMathToken(), parseMath(), and substituteFieldValues().

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◆ parseMath()

ilDclExpressionParser::parseMath ( array $tokens )

protected

Parse a math expression.

Exceptions

Exception

Definition at line 254 of file class.ilDclExpressionParser.php.

                                               : ?string
    {
        $operators = self::$operators;
        $precedence = 0;
        $stack = new ilDclStack();
        $precedences = new ilDclStack();
        $in_bracket = false;
        foreach ($tokens as $token) {
            if (empty($token) or is_null($token)) {
                $token = 0;
            }
            if (is_numeric($token) or $token === '(') {
                $stack->push($token);
                if ($token === '(') {
                    $in_bracket = true;
                }
            } elseif (in_array($token, array_keys($operators))) {
                $new_precedence = $operators[$token]['precedence'];
                if ($new_precedence > $precedence || $in_bracket) {
                    // Precedence of operator is higher, push operator on stack
                    $stack->push($token);
                    $precedences->push($new_precedence);
                    $precedence = $new_precedence;
                } else {
                    // Precedence is equal or lower, calculate result on stack
                    while ($new_precedence <= $precedence && $stack->count() > 1) {
                        $right = (float) $stack->pop();
                        $operator = $stack->pop();
                        $left = (float) $stack->pop();
                        $result = $this->calculate($operator, $left, $right);
                        $stack->push($result);
                        $precedence = $precedences->pop();
                    }
                    $stack->push($token);
                    $precedence = $new_precedence;
                    $precedences->push($new_precedence);
                }
            } elseif ($token === ')') {
                // Need to calculate stack back to opening bracket
                $_tokens = array();
                $elem = $stack->pop();
                while ($elem !== '(' && !$stack->isEmpty()) {
                    $_tokens[] = $elem;
                    $elem = $stack->pop();
                }
                // Get result within brackets recursive and push to stack
                $stack->push($this->parseMath(array_reverse($_tokens)));
                $in_bracket = false;
            } else {
                throw new ilException("Unrecognized token '$token'");
            }
            // $stack->debug();
        }
        // If one element is left on stack, we are done. Otherwise calculate
        if ($stack->count() == 1) {
            $result = $stack->pop();
 
            return (ctype_digit((string) $result)) ? $result : number_format($result, self::N_DECIMALS, '.', "'");
        } else {
            while ($stack->count() >= 2) {
                $right = $stack->pop();
                $operator = $stack->pop();
                $left = $stack->count() ? $stack->pop() : 0;
                $stack->push($this->calculate($operator, $left, $right));
            }
            $result = $stack->pop();
 
            return $result;
        }
    }

References $operators, $token, calculate(), and parseMath().

Referenced by parse(), and parseMath().

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◆ substituteFieldValues()

ilDclExpressionParser::substituteFieldValues ( array $tokens )

protected

Given an array of tokens, replace each token that is a placeholder (e.g.

[[Field name]]) with it's value

Definition at line 204 of file class.ilDclExpressionParser.php.

                                                           : array
    {
        $replaced = array();
        foreach ($tokens as $token) {
            if (strpos($token, '[[') === 0) {
                $replaced[] = $this->substituteFieldValue($token);
            } else {
                $replaced[] = $token;
            }
        }
 
        return $replaced;
    }

References $token.

Referenced by calculateFunctions(), and parse().

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Field Documentation

◆ $cache_fields

array ilDclExpressionParser::$cache_fields = array()

staticprotected

Definition at line 37 of file class.ilDclExpressionParser.php.

◆ $cache_math_function_tokens

array ilDclExpressionParser::$cache_math_function_tokens = array()

staticprotected

Definition at line 39 of file class.ilDclExpressionParser.php.

◆ $cache_math_tokens

array ilDclExpressionParser::$cache_math_tokens = array()

staticprotected

Definition at line 38 of file class.ilDclExpressionParser.php.

◆ $cache_tokens

array ilDclExpressionParser::$cache_tokens = array()

staticprotected

Definition at line 36 of file class.ilDclExpressionParser.php.

◆ $expression

string ilDclExpressionParser::$expression

protected

Definition at line 27 of file class.ilDclExpressionParser.php.

Referenced by __construct().

◆ $field

ilDclBaseFieldModel ilDclExpressionParser::$field

protected

Definition at line 26 of file class.ilDclExpressionParser.php.

Referenced by __construct().

◆ $functions

array ilDclExpressionParser::$functions

staticprotected

Initial value:

= array(
            'SUM',
            'AVERAGE',
            'MIN',
            'MAX',
        )

Definition at line 40 of file class.ilDclExpressionParser.php.

Referenced by getFunctions(), and isMathToken().

◆ $operators

array ilDclExpressionParser::$operators

staticprotected

Initial value:

= array(
            '+' => array('precedence' => 1),
            '-' => array('precedence' => 1),
            '*' => array('precedence' => 2),
            '/' => array('precedence' => 2),
            '^' => array('precedence' => 3),
        )

Definition at line 28 of file class.ilDclExpressionParser.php.

Referenced by getOperators(), isMathToken(), and parseMath().

◆ $record

ilDclBaseRecordModel ilDclExpressionParser::$record

protected

Definition at line 25 of file class.ilDclExpressionParser.php.

Referenced by __construct().

◆ N_DECIMALS

const ilDclExpressionParser::N_DECIMALS = 1

Definition at line 21 of file class.ilDclExpressionParser.php.

◆ SCIENTIFIC_NOTATION_LOWER

const ilDclExpressionParser::SCIENTIFIC_NOTATION_LOWER = 0.000000001

Definition at line 23 of file class.ilDclExpressionParser.php.

◆ SCIENTIFIC_NOTATION_UPPER

const ilDclExpressionParser::SCIENTIFIC_NOTATION_UPPER = 1000000000000

Definition at line 22 of file class.ilDclExpressionParser.php.

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

Modules/DataCollection/classes/Fields/Formula/class.ilDclExpressionParser.php

Public Member Functions

Static Public Member Functions

Data Fields

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ calculate()

◆ calculateFunction()

◆ calculateFunctions()

◆ formatScientific()

◆ getFunctionArgs()

◆ getFunctions()

◆ getOperators()

◆ isMathToken()

◆ parse()

◆ parseMath()

◆ substituteFieldValues()

Field Documentation

◆ $cache_fields

◆ $cache_math_function_tokens

◆ $cache_math_tokens

◆ $cache_tokens

◆ $expression

◆ $field

◆ $functions

◆ $operators

◆ $record

◆ N_DECIMALS

◆ SCIENTIFIC_NOTATION_LOWER

◆ SCIENTIFIC_NOTATION_UPPER