On 11/26/2013 10:24 AM, John Cowan wrote:
> Michael Montague scripsit:
>
>> I don't think that these are strong arguments for having
>> 'valid-sre?'. An implementation for which compiling is expensive,
>> could easily internally do the "is it valid"-type check before
>> compiling. Having it in the interface adds no functionality that is
>> not already easily available.
> It tells the compiler only to syntax-check and not go on to actually
> compile.  This is a very common feature in compilers: for example,
> in gcc the -fsyntax-only option activates this mode.  Sometimes
> all you want to know at present is whether something is syntactically valid.
>

The only use case for 'valid-sre?' mentioned so far is Peter's
interactive regular expression IDE. The C standard does not require the
-fsyntax-only option. These do not seem like compelling arguments for
including
'valid-sre?'.