The stupidest part of the whole thing is that pdf is basically a neutered postscript. The problem with postscript as a document format, is that there is no good

The stupidest part of the whole thing is that pdf is basically a neutered postscript. The problem with postscript as a document format, is that there is no good way to do metadata, jump to a specific page, count pages, etc. So pdf uses the rendering engine of postscript with all that annoying turing complete behavior torn out. Then at some point they wanted some computational capability in the document[1], but instead of reintroducing postscript into the mix they went with a third language, a wierd poorly designed one invent for browser scripting. 1. Yes we all know how stupid this was. but they wanted fillable forms and validating those forms made sense at the time. Really it was because they were trying to compete with the web.