On 12/10/2013 01:28 PM, Linda Walsh wrote: > > An option: > > shopt -s regex=(basic|[extended]|pcre) > where 'extended' is the default would be a > great extension.
But before bash takes on another library, it would be nicer to FIRST get libc patched to provide pcre regex by default. In other words, I think you are better off lobbying with the POSIX folks to standardize pcre as a third mode of regex worth including in libc, than you are to propose adding it to bash but letting all other regex programs (sed, grep, awk, ...) be stuck implementing pcre by themselves and possibly differently than how bash did it. Again, Chet's concern here is that the easiest way to support a particular regex syntax is to have that syntax built into the system libraries, so that ALL programs can use the same library and get the same syntax. > > Likely bash could just copy the re-engine selection and use-code from > grep... Grep uses a third-party library (libpcre) to provide it's third syntax; if that library is not present at compilation, then you can't use that flavor. So maybe bash could look into using libpcre as well. But my personal problem with libpcre is that it is bloat: bash is already bigger than dash, and requiring yet another third party library will further swing the balance away from bash for the systems that want their POSIX 'sh' to be small rather than bloated. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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