Is w:en:String-searching_algorithm possible with wiki? I need it to look for whether an input value given for a template contain the specific characters "[[" for wikilinking, so that the template can automatically remove extra brackets if they were manually added.
I am looking specifically for merging Clickable_buttons and similar templates that break with extra link brackets
No, I am looking for something like "w:en:Module:String". I think templates "Str find" and "Replace" would suffice
In this case you got the central point already.
I could recommend w:de:Wikipedia:Lua/Modul/WLink/en #getPlain which will have stripped off any link syntax.
However, you might fail to detect any {{ within template parameters since they have been resolved (expanded) already at the time the parameter value is passed to the receiving template. Supposed they have been properly balanced.
