Stop integer addition from removing strings it can't be applied to

When processing strings in the parser you can use integer addition to turn a 1 to a 2 etc etc. Very useful as regex can't normally do this from what I have seen, but when this is done it also filters out anything that is not an integer.

This is a problem for me, cause I am trying to use the parser to pull from a site that has the main page that hides the other pages, instead it shows the first 10 page's links and their thumbnail links. these thumbnail links are the only way I see of pulling the actual file.

I was going to pull the thumbnail link send it to a second parser for the thumbnail links that will then edit the link in a formula to point to the fullsized version. If that link pulls a download it would trigger the next gallery page formula which would split the link into 3 strings, add 1 to pull the next page, and then join them into the next page link.

It would just pull every page from what I know until there are no more downloads, but after it splits and I add the integer it filters out the rest of the link so it can't be rejoined.

I was very tired when I made it, so there is probably some other way to do this, but also I don't get why integer addition acts like a filter regardless.

No file or test is named. Start by reproducing integer addition on a parser value containing both numeric and non-numeric string parts, then locate the parser implementation and its existing tests. Done means integer segments can be incremented without discarding the other link segments, with coverage for this mixed-string case.