How can I convert an array into a php statement? - php

Question

I have an array like this...
[Summary] => Array
(
[0] => yearManufactured
[1] => &&
[2] => make
[3] => ||
[4] => model
)
how can I convert this array into function calls and operators and then use it to make a comparision, for example turn it into this...
if( $this->yearManufactured() && $this->make() || $this->model() ) {
// do something
} else {
// do something else
}
Methods in class..
public function yearManufactured() {
return true;
}
public function make() {
return false;
}
public function model() {
return true;
}

Answer 1

This seems like something that could actually be a valid use for eval. You can verify that each array item is either an operator or a valid method name, and convert the result of the method call to a boolean string. Putting those things together should result in a string that you can safely eval without worrying about it doing something nasty, other than maybe causing a parse error, which can be caught in PHP 7.
If you find anything in the array that isn't supposed to be there, or the expression doesn't parse, you can return null, or throw an exception, however you want to handle it.
public function evaluateExpressionArray(array $expression) {
// build the expression
$expr = '$result =';
foreach ($expression as $part) {
if ($part == '||' || $part == '&&') {
$expr .= " $part ";
} elseif (method_exists($this, $part)) {
$expr .= $this->$part() ? 'true' : 'false';
} else {
return null;
}
}
// try to evaluate it
try {
eval("$expr;");
} catch (ParseError $e) {
return null;
}
return $result;
}
Be very careful with eval, though. Don't ever put anything into it unless you know exactly what it is.
Here's an example to mess with.