On Nov 13, 2003, at 11:47 AM, Dar Scott wrote:
Strings do just fine with ASCII NUL (0) and EOT (4). The Revolution EOF is encoded as 4, also.
A few features have trouble with some values. For example, you can't have a NUL in an array key.
I have seen (some versions back) NULs cause trouble in fields. They mess up display and the data gotten back is garbled. The last I looked, IIRC, the docs recommended avoiding any control characters in fields other than tab and the end of line (LF in Rev).
I don't know of a way somebody might type those. I have some vague memory of holding down some key and typing digits in Windows. I have not tried that with Revolution.
Typing isn't the problem for the most part - it's copy-pasting from other apps into a Rev field. I am going to implement pasteKey and do a replacetext in there - removing all the control characters that you mention.
I am not sure I understand.
Is this because you open a pipe to a process and that process looks for the EOF character instead of a close?
Or is this because it makes a mess of parsing?
Actually, it turns out the CLIPS docs were wrong- and it allows all characters in strings, except quotes are delimiters so must they escaped like \".
What happened however, did involve file IO and that's where the EOF caused trouble. The scenario was like this:
-- User pastes some text into Rev a app
-- Transcript handler gets the text and calls a CLIPS external function with that text as part of the parameter.
-- CLIPS runs, and saves it's state out to a file
-- CLIPS later reads the state in the file.
-- CLIPS finds EOF in the middle of a string and gives up parsing the data.
The limits, I think, to data passed to an external include the string being null terminated and some sort of 64K limit. I don't remember whether the latter is for the entire call or a single parameter.
If the CLIPS library has a character set limitation, it would be reasonable to matchText() on that in any case. I'd put that in and then use that to track down the source.
Thanks for your feedback Dar! I had a feeling you would be the one to answer this one :-)
Alex Rice <[EMAIL PROTECTED]> | Mindlube Software | <http://mindlube.com>
what a waste of thumbs that are opposable to make machines that are disposable -Ani DiFranco
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