invisible Return issue to know about
coiin at verizon.net
Mon Sep 19 11:56:00 EDT 2011
A card script that I had made using 4.6.1 was causing a script error in a button when used in 4.6.4. The button script had no problem, but it did call into an unrelated handler in the same card script where the problem line was.
It turned out that one line in that card script had an invisible line feed character in it. The way line feeds is handled changed in 4.6.3, and whereas before scripts could have such line feed characters in them without a problem, now they can't.
There was a clue to where the problem was, in that on opening the stack there was a script error that showed for the line after the one that was the real problem. The line it claimed was wrong had no problems, but because of the line feed character the error was really referring to the second half of the line before the one that was referring to.
Aside from using a bit of abstract thinking to figure it all out, one clue to there being a rogue line feed character is that if you comment out the script, the letters after where the line feed is located don't turn green. If that happens, selecting the line and retyping exactly what you see will fix it.
So, if you have a stack that worked fine with 4.6.2, but shows problems in 4.6.3 or later, and the line that it's complaining about seems perfectly good, comment out the line before that one, and see if the text all turns green. If it doesn't, retype the line.
I suspect the line feed got in there in the first place by me copying and pasting an example line of code from the documentation. Not the Help perhaps, but the earlier iPhone docs.
More information about the Use-livecode