\n isn't literally \n.

If you aren't using a multi-line input then you'll need to manually find and replace \n.

Neither trog, it's upon using the user submitted value in text, I want to put it in as what they intended the characters to mean, not as the text that they entered.

I'll just use this

$replace = array(
'\n' => "\n",
'\r' => "\r",
'\t' => "\t",
'\v' => "\v",
'\e' => "\e",
'\f' => "\f",
);
return str_replace(array_keys($replace), array_values($replace), $string);

That covers all the weird untypable things.

The user isn't typing quotes in. I just wanted what they typed in, in a single line textfield, to behave as though it was hardcoded into the code with double quotes around it.

I guess I could add double quotes around it and eval it... !
But my str_replace thing seems to be working.

last edited by thermite at 15:15:35 16/May/12

Yeah the only reason I mentioned single and double quotes is because I can't find the words to explain what I'm saying. So I couldn't google this problem either.
The user isn't supplying any other text. That comes from elsewhere.

Looks like he has a single line input box, someone can come along and enter text \n like this \n and it'll automatically replace \n the backslash n with a newline character.

Why the hell not have a multi line input box? I can't imagine entering a whole paragraph of text on a single line with a bunch of \n's will be ideal.

Does it have to be stupidly flexible with weird and wonderful line ending markers?
I'd be tempted to constrain it if possible and change the text input to a drop down that has three options: CR, LF, and CRLF

Yeah the only reason I mentioned single and double quotes is because I can't find the words to explain what I'm saying. So I couldn't google this problem either.
The user isn't supplying any other text. That comes from elsewhere.

I think the commonly used term for them is still just single quoted and double quoted string literals, but I think double quoted string literals are also referred to as something like variable-parsed string literals. Unfortunately I'm pretty sure there's no simple way to parse a string variable in the same way that a double quoted string literal is parsed by PHP.

I think the closest you're going to get to exactly what you were looking for is by using eval, which is very undesirable because it can literally run any maliciously injected code if the user knows how the variable is eval'd by your code. But this line of code will do what you're looking for:

eval("\$str = \"$str\";");

In the end, though, I think your solution of just replacing characters in the string is probably simpler and safer.