[JW Lua] Automatic float to integer conversion ... Lua 5.3 ?!

Jan Angermüller jan at angermueller.com
Tue Nov 10 17:22:53 CET 2015


Yes, Bruce, that is definitely the same bug.
Now I've already been fixing for six hours ... that's really a very 
annoying behaviour ...
but hopefully 5.3 will bring some new features. Maybe even a debugging 
feature ?

Am 10.11.2015 um 17:03 schrieb Bruce Olson:
>
> Jan,
>
> Thanks for tracking down the documentation. I found the same error on 
> Sunday, see the *PageFormatPrefs.SystemStaffHeight error: bad argument 
> #2 to '?' (number has no integer representation)* message I sent on 
> Sunday last.
>
> -- 
>
> Regards,
>
> Bruce
>
> *From:*JWLua [mailto:jwlua-bounces at jwmusic.nu] *On Behalf Of *Charles 
> O. Lawrence
> *Sent:* Tuesday, November 10, 2015 8:16 AM
> *To:* 'The JW Lua script plug-in.'
> *Subject:* Re: [JW Lua] Automatic float to integer conversion ... Lua 
> 5.3 ?!
>
> Jan,
>
> Interesting info.  I think you hit on the answer to the strange errors.
>
> Charles
>
> *From:*JWLua [mailto:jwlua-bounces at jwmusic.nu] *On Behalf Of *Jan 
> Angermüller
> *Sent:* Tuesday, November 10, 2015 8:11 AM
> *To:* The JW Lua script plug-in. <jwlua at jwmusic.nu 
> <mailto:jwlua at jwmusic.nu>>
> *Subject:* Re: [JW Lua] Automatic float to integer conversion ... Lua 
> 5.3 ?!
>
> Probably this is due to a change in Lua 5.3:
> the chapter on integer/float conversion is new ( 
> http://www.lua.org/manual/5.3/manual.html#3.4.3 ) and didn't exist for 
> Lua 5.2.
> It states:
> "The conversion from float to integer checks whether the float has an 
> *exact *representation as an integer (that is, the float has an 
> integral value and it is in the range of integer representation). If 
> it does, that representation is the result. Otherwise, the conversion 
> *fails*."
>
> Lesson learned:
> *Don't assign float types to properties that expect integers in Lua 
> 5.3.* *
> They will not be automatically converted to integers anymore.*
>
> This document gives a good overview of the new integer/float handling 
> in Lua 5.3:
> http://www.lua.org/wshop14/Ierusalimschy.pdf
>
> So it seems that I will have a lot of fails now...
> Bad luck then ... at least it leads to a cleaner code in the end.
>
> Jan
>
> Am 10.11.2015 um 11:08 schrieb Jan Angermüller:
>
>     Jari,
>
>     I am trying to make my scripts compatible with v.40/v.42 and get
>     lots of bad argument errors as Charles described some days ago
>     ("Strange Error Message"-thread), although with different
>     descriptions, for example:
>     bad argument #2 to '?' (number has no integer representation)
>     And in my case*these errors have not occured when running the
>     scripts in previous versions of JW Lua.*
>
>     For example:
>     (a is an FCArticulationDef)
>     a.MainHandleVerticalOffset=a.MainHandleVerticalOffset+vertoffset
>     It used to work fine for any vertoffset value, even with
>     vertoffset being a float type.
>     Now it throws the error message above WITHOUT the code line and
>     requires an explicit integer conversion to work:
>     a.MainHandleVerticalOffset=a.MainHandleVerticalOffset+math.floor(vertoffset)
>
>     Although the error message is technically correct (a float is not
>     an integer), the automatic type conversion used to work fine.
>     That will be probably be days of work to fix in more than 30.000
>     lines of code if you have to track down every error without a
>     debugger.
>
>     What's the reason for the new error message ? Is it a stricter
>     parser or Lua 5.3 or anything else ?
>     Do you see any chance of solving that without having to rewrite
>     all the code.
>     Or at least add the code line when a "Bad Argument" error is thrown ?
>
>     All the best,
>     Jan
>
>     Am 28.10.2015 um 22:40 schrieb Charles O. Lawrence:
>
>         Jari,
>
>         Sometimes when running a script I get an error message like
>         this.  There is no line number nor is there a red marker at
>         any source line.  It makes locating the problem rather
>         difficult in a large script. Any ideas?  Beta 0.42
>
>         bad argument #2 to '?' (number expected, got boolean)
>
>         Thanks,Charles
>
>         Sorry, I left off the subject
>
>
>
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