Question

What’s the best way to take some plain text (not PHP code) which contains PHP-style variables, and then substitute in the value of the variable. This is kinda hard to describe, so here’s an example.

// -- myFile.txt -- Mary had a little $pet.  // -- parser.php -- $pet = 'lamb'; // open myFile.txt and transform it such that... $newContents = 'Mary had a little lamb.'; 

I’ve been considering using a regex or perhaps eval(), though I’m not sure which would be easiest. This script is only going to be running locally, so any worries regarding security issues and eval() do not apply (i think?).

I’ll also just add that I can get all the necessary variables into an array by using get_defined_vars():

$allVars = get_defined_vars(); echo $pet;             // 'lamb' echo $allVars['pet'];  // 'lamb' 

Answer 1

If it’s from a trusted source you can use (dramatic pause) eval() (gasps of horror from the audience).

$text = 'this is a $test'; // single quotes to simulate getting it from a file $test = 'banana'; $text = eval('return '' . addslashes($text) . '';'); echo $text; // this is a banana