What autocomplete you need in J? For verbs and conjunctions which are at most 2 letters long?
> how do you give ideas whether the user should use @ or ^ at a given point?
In the same way as IDE helps you to choose . or exp() ? They are completely different concepts, how can you mix them?
> it's near impossible to search for code examples and such
I think it's a common problem for complex code examples, in any language. You may, though, search for comments.
From http://www.jsoftware.com/help/jforc/foreword.htm#_Toc1917342... :
> C is a computer language; it lets you control the things the computer does. J is a language of computation: it lets you describe what needs to be done without getting bogged down in details
I think it's a great help. J doesn't just reduces typing; it also reduces the amount of things one needs to keep in the head to solve the problem.
I even coerced SES (the Emacs spreadsheet) to act as an editor for large arrays.
I would argue that I have suceeded at least partially, such that I can say that it's definitely possible to implement an IDE for APL.