[GiNaC-devel] Parser breakage changes

Alexei Sheplyakov varg at metalica.kh.ua
Mon Aug 3 09:11:32 CEST 2009


Dear Jens,

On Fri, Jul 31, 2009 at 01:07:37PM +0200, Jens Vollinga wrote:

> because the parser as it was violated the basic assumption (not only  
> that of the people that complained but also mine!) that the parser,  
> without any tweaking, should just read any expression containing any  
> functions and classes defined at that moment.

I think this assumption is bogus. Just because you've defined a (C++) type
(class) doesn't mean you can print and/or parse objects of that type. Anyway,
the old (bison-generated) parser never 'just read any expression containing
any functions and classes defined at that moment' (actually it didn't handle
any user defined classes at all).

> A user shouldn't be forced to define his own reader just to get a simple
> expression read in 

Making a type printable/readable (and/or serializable) always requires some
boilerplate code.

> Yeah, more boilerplate code, right, but now only people with special  
> needs have to go through this hassle and not the average user anymore.

"A million lemmings can't be wrong"-alike arguments do nothing useful and
make some people (including myself) very angry.

Best regards,
	Alexei



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