ILIAS  release_5-2 Revision v5.2.25-18-g3f80b828510
ilDclExpressionParser Class Reference

Class ilDclExpressionParser. More...

+ Collaboration diagram for ilDclExpressionParser:

Public Member Functions

 __construct ($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 ($token)
 Check if a given token is a math expression. More...
 
 calculateFunctions ($token)
 Execute any math functions inside a token. More...
 
 getFunctionArgs ($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 ($function, array $args=array())
 Calculate a function with its arguments. More...
 
 calculate ($operator, $left, $right)
 

Protected Attributes

 $record
 
 $field
 
 $expression
 

Static Protected Attributes

static $operators
 
static $cache_tokens = array()
 
static $cache_fields = array()
 
static $cache_math_tokens = array()
 
static $cache_math_function_tokens = array()
 
static $functions
 

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

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

Definition at line 68 of file class.ilDclExpressionParser.php.

References $expression, $field, and $record.

Member Function Documentation

◆ calculate()

ilDclExpressionParser::calculate (   $operator,
  $left,
  $right 
)
protected
Parameters
string$operator
float$left
float$right
Returns
float|number
Exceptions
ilException

Definition at line 417 of file class.ilDclExpressionParser.php.

417 {
418 switch ($operator) {
419 case '+':
420 $result = $left + $right;
421 break;
422 case '-':
423 $result = $left - $right;
424 break;
425 case '*':
426 $result = $left * $right;
427 break;
428 case '/':
429 $result = ($right == 0) ? 0 : $left / $right;
430 break;
431 case '^':
432 $result = pow($left, $right);
433 break;
434 default:
435 throw new ilException("Unrecognized operator '$operator'");
436 }
437
438 return $result;
439 }
$result
Base class for ILIAS Exception handling.

References $result.

Referenced by parseMath().

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◆ calculateFunction()

ilDclExpressionParser::calculateFunction (   $function,
array  $args = array() 
)
protected

Calculate a function with its arguments.

Parameters
$functionFunction name to calculate
array$argsArguments of function
Returns
float|int|number
Exceptions
ilException

Definition at line 391 of file class.ilDclExpressionParser.php.

391 {
392 switch ($function) {
393 case 'AVERAGE':
394 $count = count($args);
395
396 return ($count) ? array_sum($args) / $count : 0;
397 case 'SUM':
398 return array_sum($args);
399 case 'MIN':
400 return min($args);
401 case 'MAX':
402 return max($args);
403 default:
404 throw new ilException("Unrecognized function '$function'");
405 }
406 }

Referenced by calculateFunctions().

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◆ calculateFunctions()

ilDclExpressionParser::calculateFunctions (   $token)
protected

Execute any math functions inside a token.

Parameters
string$token
Returns
string

Definition at line 187 of file class.ilDclExpressionParser.php.

187 {
188 if (isset(self::$cache_math_function_tokens[$this->field->getId()][$token])) {
189 $result = self::$cache_math_function_tokens[$this->field->getId()][$token];
190 if ($result === false) {
191 return $token;
192 }
193 } else {
194 $pattern = '#';
195 foreach (self::getFunctions() as $function) {
196 $pattern .= "($function)\\(([^)]*)\\)|";
197 }
198 if (!preg_match_all(rtrim($pattern, '|') . '#', $token, $result)) {
199 // No functions found inside token, just return token again
200 self::$cache_math_function_tokens[$this->field->getId()][$token] = false;
201
202 return $token;
203 }
204 }
205 // Function found inside token, calculate!
206 foreach ($result[0] as $k => $to_replace) {
207 $function_args = $this->getFunctionArgs($k, $result);
208 $function = $function_args['function'];
209 $args = $this->substituteFieldValues($function_args['args']);
210 $token = str_replace($to_replace, $this->calculateFunction($function, $args), $token);
211 }
212
213 return $token;
214 }
substituteFieldValues(array $tokens)
Given an array of tokens, replace each token that is a placeholder (e.g.
getFunctionArgs($index, array $data)
Helper method to return the function and its arguments from a preg_replace_all $result array.
calculateFunction($function, array $args=array())
Calculate a function with its arguments.

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

Referenced by parse().

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◆ formatScientific()

ilDclExpressionParser::formatScientific (   $value)
protected
Parameters
$value
Returns
string

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

125 {
126 if (abs($value) >= self::SCIENTIFIC_NOTATION_UPPER) {
127 return sprintf("%e", $value);
128 }
129 if (abs($value) <= self::SCIENTIFIC_NOTATION_LOWER && $value != 0 ) {
130 return sprintf("%e", $value);
131 }
132 if (is_float($value)) {
133 return $value;
134 }
135
136 return $value;
137 }
sprintf('%.4f', $callTime)

References sprintf.

Referenced by parse().

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◆ getFunctionArgs()

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

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

Parameters
$index
array$data
Returns
array

Definition at line 225 of file class.ilDclExpressionParser.php.

225 {
226 $return = array(
227 'function' => '',
228 'args' => array(),
229 );
230 for ($i = 1; $i < count($data); $i ++) {
231 $_data = $data[$i];
232 if ($_data[$index]) {
233 $function = $_data[$index];
234 $args = explode(';', $data[$i + 1][$index]);
235 $return['function'] = $function;
236 $return['args'] = $args;
237 break;
238 }
239 }
240
241 return $return;
242 }

References $data.

Referenced by calculateFunctions().

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◆ getFunctions()

static ilDclExpressionParser::getFunctions ( )
static
Returns
array

Definition at line 151 of file class.ilDclExpressionParser.php.

151 {
152 return self::$functions;
153 }

References $functions.

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

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◆ getOperators()

static ilDclExpressionParser::getOperators ( )
static
Returns
array

Definition at line 143 of file class.ilDclExpressionParser.php.

143 {
144 return self::$operators;
145 }

References $operators.

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

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◆ isMathToken()

ilDclExpressionParser::isMathToken (   $token)
protected

Check if a given token is a math expression.

Parameters
string$token
Returns
bool

Definition at line 163 of file class.ilDclExpressionParser.php.

163 {
164 if (isset(self::$cache_math_tokens[$this->field->getId()][$token])) {
165 return self::$cache_math_tokens[$this->field->getId()][$token];
166 } else {
167 if (strpos($token, '"') === 0) {
168 return false;
169 }
170 $operators = array_keys(self::getOperators());
172 $result = (bool)preg_match('#(\\' . implode("|\\", $operators) . '|' . implode('|', $functions) . ')#', $token);
173 self::$cache_math_tokens[$this->field->getId()][$token] = $result;
174
175 return $result;
176 }
177 }

References $functions, $operators, $result, 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
Returns
string

Definition at line 83 of file class.ilDclExpressionParser.php.

83 {
84 if (isset(self::$cache_tokens[$this->field->getId()])) {
85 $tokens = self::$cache_tokens[$this->field->getId()];
86 } else {
87 $tokens = ilDclTokenizer::getTokens($this->expression);
88 self::$cache_tokens[$this->field->getId()] = $tokens;
89 }
90 // ilUtil::sendInfo( "<pre>" . print_r($tokens, 1) . "</pre>");
91 $parsed = '';
92 foreach ($tokens as $token) {
93 if (empty($token)) {
94 continue;
95 }
96 if ($this->isMathToken($token)) {
97 $token = $this->calculateFunctions($token);
98 $math_tokens = ilDclTokenizer::getMathTokens($token);
99 $value = $this->parseMath($this->substituteFieldValues($math_tokens));
100
101 $value = $this->formatScientific($value);
102
103 $parsed .= $value;
104 } else {
105 // Token is a string, either a field placeholder [[Field name]] or a string starting with "
106 if (strpos($token, '"') === 0) {
107 $parsed .= strip_tags(trim($token, '"'));
108 } elseif (strpos($token, '[[') === 0) {
109 $parsed .= trim(strip_tags($this->substituteFieldValue($token)));
110 } else {
111 throw new ilException("Unrecognized string token: '$token'");
112 }
113 }
114 }
115
116 return $parsed;
117 }
calculateFunctions($token)
Execute any math functions inside a token.
parseMath(array $tokens)
Parse a math expression.
isMathToken($token)
Check if a given token is a math expression.
static getMathTokens($math_expression)
Generate tokens for a math expression.
static getTokens($expression)

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

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◆ parseMath()

ilDclExpressionParser::parseMath ( array  $tokens)
protected

Parse a math expression.

Parameters
array$tokens
Returns
null
Exceptions
Exception

Definition at line 310 of file class.ilDclExpressionParser.php.

310 {
312 $precedence = 0;
313 $stack = new ilDclStack();
314 $precedences = new ilDclStack();
315 $in_bracket = false;
316 foreach ($tokens as $token) {
317 if (empty($token) OR is_null($token)) {
318 $token = 0;
319 }
320 if (is_numeric($token) OR $token === '(') {
321 $stack->push($token);
322 if ($token === '(') {
323 $in_bracket = true;
324 }
325 } elseif (in_array($token, array_keys($operators))) {
326 $new_precedence = $operators[$token]['precedence'];
327 if ($new_precedence > $precedence || $in_bracket) {
328 // Precedence of operator is higher, push operator on stack
329 $stack->push($token);
330 $precedences->push($new_precedence);
331 $precedence = $new_precedence;
332 } else {
333 // Precedence is equal or lower, calculate result on stack
334 while ($new_precedence <= $precedence && $stack->count() > 1) {
335 $right = (float)$stack->pop();
336 $operator = $stack->pop();
337 $left = (float)$stack->pop();
338 $result = $this->calculate($operator, $left, $right);
339 $stack->push($result);
340 $precedence = $precedences->pop();
341 }
342 $stack->push($token);
343 $precedence = $new_precedence;
344 $precedences->push($new_precedence);
345 }
346 } elseif ($token === ')') {
347 // Need to calculate stack back to opening bracket
348 $_tokens = array();
349 $elem = $stack->pop();
350 while ($elem !== '(' && !$stack->isEmpty()) {
351 $_tokens[] = $elem;
352 $elem = $stack->pop();
353 }
354 // Get result within brackets recursive and push to stack
355 $stack->push($this->parseMath(array_reverse($_tokens)));
356 $in_bracket = false;
357 } else {
358 throw new ilException("Unrecognized token '$token'");
359 }
360 // $stack->debug();
361 }
362 // If one element is left on stack, we are done. Otherwise calculate
363 if ($stack->count() == 1) {
364 $result = $stack->pop();
365
366 return (ctype_digit((string)$result)) ? $result : number_format($result, self::N_DECIMALS, '.', "'");
367 } else {
368
369 while ($stack->count() >= 2) {
370 $right = $stack->pop();
371 $operator = $stack->pop();
372 $left = $stack->count() ? $stack->pop() : 0;
373 $stack->push($this->calculate($operator, $left, $right));
374 }
375 $result = $stack->pop();
376
377 return $result;
378 }
379 }
calculate($operator, $left, $right)
Class ilDclStack.

References $operators, $result, 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

Parameters
array$tokens
Returns
array

Definition at line 252 of file class.ilDclExpressionParser.php.

252 {
253 $replaced = array();
254 foreach ($tokens as $token) {
255 if (strpos($token, '[[') === 0) {
256 $replaced[] = $this->substituteFieldValue($token);
257 } else {
258 $replaced[] = $token;
259 }
260 }
261
262 return $replaced;
263 }

Referenced by calculateFunctions(), and parse().

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Field Documentation

◆ $cache_fields

ilDclExpressionParser::$cache_fields = array()
staticprotected

Definition at line 43 of file class.ilDclExpressionParser.php.

◆ $cache_math_function_tokens

ilDclExpressionParser::$cache_math_function_tokens = array()
staticprotected

Definition at line 51 of file class.ilDclExpressionParser.php.

◆ $cache_math_tokens

ilDclExpressionParser::$cache_math_tokens = array()
staticprotected

Definition at line 47 of file class.ilDclExpressionParser.php.

◆ $cache_tokens

ilDclExpressionParser::$cache_tokens = array()
staticprotected

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

◆ $expression

ilDclExpressionParser::$expression
protected

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

Referenced by __construct().

◆ $field

ilDclExpressionParser::$field
protected

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

Referenced by __construct().

◆ $functions

ilDclExpressionParser::$functions
staticprotected
Initial value:
= array(
'SUM',
'AVERAGE',
'MIN',
'MAX',
)

Definition at line 55 of file class.ilDclExpressionParser.php.

Referenced by getFunctions(), and isMathToken().

◆ $operators

ilDclExpressionParser::$operators
staticprotected
Initial value:
= array(
'+' => array( 'precedence' => 1 ),
'-' => array( 'precedence' => 1 ),
'*' => array( 'precedence' => 2 ),
'/' => array( 'precedence' => 2 ),
'^' => array( 'precedence' => 3 ),
)

Definition at line 29 of file class.ilDclExpressionParser.php.

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

◆ $record

ilDclExpressionParser::$record
protected

Definition at line 17 of file class.ilDclExpressionParser.php.

Referenced by __construct().

◆ N_DECIMALS

const ilDclExpressionParser::N_DECIMALS = 1

Definition at line 11 of file class.ilDclExpressionParser.php.

◆ SCIENTIFIC_NOTATION_LOWER

const ilDclExpressionParser::SCIENTIFIC_NOTATION_LOWER = 0.000000001

Definition at line 13 of file class.ilDclExpressionParser.php.

◆ SCIENTIFIC_NOTATION_UPPER

const ilDclExpressionParser::SCIENTIFIC_NOTATION_UPPER = 1000000000000

Definition at line 12 of file class.ilDclExpressionParser.php.


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