Workaround for deprecated regex pattern modifier in PHP 5.5.0 and up (10.10 Yosemite)

Question

I'm relying on the Low Regex plugin to convert section handles from camelCase to lower-dash-case to use them in URLs, like so:

{section.handle|regex('/(^|[a-z])([A-Z])/e', 'strtolower(strlen("\\1") ? "\\1-\\2" : "\\2")',(section.handle))}

…and further, to convert the segment of the URL that contains the dash-separated section name to camel case, so I can work with it in my templates, like so:

{% set sectionHandle = craft.request.getFirstSegment() %}
{% set sectionHandleCc = sectionHandle | regex('/-([a-z])/e', 'strtoupper(strlen("\\1") ? "\\1\\2" : "\\2")',(sectionHandle)) %}
{% set section = craft.sections.getSectionByHandle(sectionHandleCc) %}

Now, OS X 10.10 Yosemite ships with PHP version 5.5.14 pre-installed and as of 5.5.0 the e-modifier for regex patterns is deprecated, so on my local machine I get this error and the site breaks:

I got in touch with the plugin author and he suggested removing the e-modifier, which seemed to work within the templates, but when I removed the modifier in the sections entry URL format the CP wasn't able to re-save my entries and I couldn't save new entries either.

The question that remains is: Is there a workaround using a different regex pattern or – and that would be my preferred scenario – is there an approach I didn't think of that allows me to omit the plugin dependency completely? I guess one option would be to keep the section handles all lowercase, but I'd like to have them dash-separated in the URLs.

Answer 1

Okay, so, thanks to carlcs' answer I managed to solve the camel-case to lower-dash-case conversion. The other direction was a bit trickier, but again, after digging in a bit deeper I was able to figure it out myself:

First off, I'm not using the plugin any longer! Yay! The secret was to create a custom Twig filter that would convert dash-separated strings like so:

{{ 'my-first-car'|dash2camel }}
{# outputs 'myFirstCar' #}

With the help of this guide and some code from this answer I created my own custom Twig filter within Craft. Nothing fancy and hacked together quickly, but I've put it on GitHub if someone runs into the same issues.

Answer 2

Can't help you with that \e modifier problem and my regex knowledge is very limited, but that camelCase problem can be solved with Twig filters:

{{ 'camelCase'|replace('/([A-Z])/', '-\\1')|lower }}