[mapserver-dev] Quote escaping in mapfile strings

[Umberto Nicoletti]

Daniel,
I think we are already using the first approach in the mapfile to
escape quotes, see maplexer.l lines 534 to 577.

Regards,
Umberto

On Wed, Jan 12, 2011 at 5:10 AM, Daniel Morissette
<dmorissette at mapgears.com> wrote:
> An issue that keeps coming back every once in a while is the lack of a
> mechanism to escape quotes (') and double quotes (") inside strings in
> mapfiles.
>
> 6.0 would be a good time to address this in case the fix implies new mapfile
> rules or limitations.
>
> The first step is to decide on the syntax to escape quotes. Can anyone think
> of a magic solution to this problem that will make everybody happy?
>
> Here are a few thoughts:
>
> 1- An obvious approach could be to use C escaping: \' , \" and \\ ... but
> unfortunately that would force the use of double \\ in all windows filename
> paths. I realize that one could use "/" on Windows instead but using this
> approach could cause unnecessary confusion with beginners and become a FAQ
> that comes up more often than the use dummy TEMPLATEs to enable queries in
> MapScript.
>
> 2- Another approach could be to use two double quotes ("") to escape a
> double quote, and two single quotes ('') to escape a single quote
>
> e.g.
>  "This string contains ""Double Quotes"""
>  'This string contains ''Single Quotes'''
>  "You don't need to escape single quotes in this string since it uses double
> quotes ("") as delimiter"
>  'And the same way "Double Quotes" don't need escaping here'
>  "Two ''single quotes'' in this string are not considered an escape sequence
> and remain two individual chars'
>
> /me thinks #2 could work with a minimum of disruption to existing mapfiles,
> unless I missed something. We'd need Steve's opinion on how this can be
> implemented in the parser.
>
> Anyone have better suggestions?
>
> Daniel
> --
> Daniel Morissette
> http://www.mapgears.com/
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