Find php variables that are used inside single quotes incorrectly

Question

I want to run a regex search from inside PhpStorm (could be any file manager though, Double/Total Commander handles regex searches just as well) to match php variables that are inside single quotes and therefore string interpolation won't work on them e.g. '$var'.

The content of the files would be something like this:

$var = 'Hello world!';

echo 'Lorem ipsum $var dolor sit amet'; // Match this.
echo "Lorem ipsum 'dolor sit amet $var consectetur' adipiscing elit"; // But not this.
echo "Lorem ipsum 'dolor sit amet \$var consectetur' adipiscing elit"; // Or this.

I want the regex search to match the first statement, but not the second or third.

I've tried '[\w ]+\$[\w]+[\w ]+' but that doesn't work because it matches all statements regardless of the double quotes or escaped dollar sign. (regex101).

This is just a regular regex search that I want to run on my repo to find buggy code.

What regex could I use for this?

_{(I don't need to get any text in between quotes, just php variables in between single quotes that aren't escaped.)}

Possible duplicate of [RegEx: Grabbing values between quotation marks](http://stackoverflow.com/questions/171480/regex-grabbing-values-between-quotation-marks) — Shira, May 20 '17 at 17:25
Just add `(?![\w$ ']+")` at the end (assuming that `\w$ '` are the only character allowed in a string)? — logi-kal, May 20 '17 at 17:59
Thanks @horcrux ! That works! Can you post an answer so I can accept it? — Ethan, May 20 '17 at 18:01
@David could you provide a working sample of horcrux's answer ? — Mostafa Hussein, May 20 '17 at 18:05
Here @MostafaHussein [regex101](https://regex101.com/r/cNpzPD/5/) `'[\w ]+\$[\w]+[\w ]+'(?![\w$ ']+")` — Ethan, May 20 '17 at 18:07

score 1 · Accepted Answer · answered May 20 '17 at 20:09

What you need is negative lookaround. In particular, negative lookahead, because in PHP you are not allowed to use no-fixed-length lookbehind:

'[\w ]+\$[\w]+[\w ]+'(?![\w$ ']*")

(?![\w$ ']*") means that the string that you want to match must not be followed by a ", with any number of character (the ones that you want to allow in a string) in the middle.

See also: http://www.regular-expressions.info/lookaround.html

Find php variables that are used inside single quotes incorrectly

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