regex for parsing a img tag in html with parameters

Question

I have this notational language for posting stuff on my blog and I use the following line to parse images

$$link_to_image width height alternative_description$$

I am parsing this with the following php sentence

preg_replace('/\$\$(.*?)\s\d+\s\d+\s(.*?)\$\$/','<img src = "\\1" width = "\\2px" height = "\\3px" alt = "\\4" >',$this->text);

where $this->text is the whole text of the blog's post.

the problem is when I enter something like $$http://s15.postimg.org/60dod0gu3/input.png 400 300 Raw data$$ I am getting

<img src="http://s15.postimg.org/60dod0gu3/input.png" width="Raw datapx" height="px" alt="">

What is wrong with the regex I wrote ?

Answer 1

You only capture 2 groups but you want 4. Add two more capturing groups for the numbers:

\$\$(.*?)\s(\d+)\s(\d+)\s(.*?)\$\$

Demo.