I haven't found any topic about the different bugs of the Lua language on the TI Nspire.
The goal of this topic is to reference all the problem here and to find solutions or explanations.
(maybe there is already a topic or a place for this, even in another web site as Inspired Lua for example ? If so, please let me know. )

So I start with some problem I had or I know.

1) The function string.find(string,substring) produce an error with this substring : "(". If we replace the searchstring by string.uchar(40), this is the same.
The error is "unfinished capture".
Why ??

It seems that this problem occurs only with "(". (If the substring is for example "(g", there is no problem.)

==> How to avoid this ?
     * creating a function like this :
function strFind(str,ch)
    local chPos
    chPos=nil
    for i=1,string.len(str) do
        if string.sub(str,i,i)==ch and not chPos then
            chPos=i
        end
    end
    return chPos
end
    * using TI Basic inString( function with Lua math.eval( function.

    * string.find(str, "%(")
=> This is the best solution. Thank you jimbauwens.
Explications two posts later.



2) The graphical bug of Levak :
you can draw in the "status bar", top of the screen.



A simple example :
function on.paint(gc)
  gc:begin()

-- draw
  gc:setFont("sansserif", "b", 10)
  gc:drawString("Hello World", 0, 0, "top")

  gc:finish()
endThe bug seems to be possible when using gc:begin() / gc:finish instructions.

==> How to avoid this ?
* You don't have to use gc:begin() / gc:finish() generally. ^^


3) (that's not really a problem, but something good to know)
math.eval function runs TI Basic instruction (in a string)
All the instructions seem to work, except :
- I/O functions : Text, Request, RequestStr, Disp
- program call
- Local function

==> How to avoid this ?
* You have to program dialog boxes yourself ! xD
* You can use toolpalette functions for choices.
* You could use D2Editor but.. see 4)
* Instead of calling a basic program, paste all the code into a string in the math.eval( function.



4) The D2Editor seems to be very usefull but we can't remove it ! So you can't really use it..

==> How to avoid this ?
* You have to program yourself a "Request" function.. ^^
Simple example :
msg = ""

function on.paint(gc)
    gc:drawString(msg,10,10,"top")
end

function on.charIn(ch)
    msg = msg .. ch
    platform.window:invalidate()
end
If you want a full code to enter text (delete, clear, insert, go to the fisrt/last character, ...) I can post code from my ABA Logique program ! ^^

So, you can post your potential problems or your solutions/explications.

Thanks

Well, the reason for the first 'bug' (it isn't actually a bug) is because "(" is a magic character.
The second argument to string.find is a pattern, so it is parsed as a pattern, and if there is an error in it it will report it. To search for "(" just escape it with "%".
Example:
string.find(str, "%(")

More info on this at http://www.lua.org/pil/20.2.html.

Anyway, nice topic

Well, maybe ")" is a valid pattern, and doesn't cause an error. I didn't look yet into the details, but I will do that later.

Ah, didn't know it could be disabled. Thanks

Why 3?
It was a cool way of fetching external data

Oh, so it will become even become better \o/
Thanks for enlightening us

Too bad 2 will be fixed, though, because the Nyan Cat game will no longer display properly :'(

Well, it's just 18px

28px