I didn't notice your email, I just saw it. Modified accordingly,
that's better! Thanks.
Le sam. 4 mai 2024 à 15:40, Waldek Hebisch <de...@fricas.org> a écrit :
>
> On Sat, May 04, 2024 at 06:43:42AM +0200, Grégory Vanuxem wrote:
> > Hello,
> >
> > I have found 'devaluate' in some Spad files and it can be handy.
> <snip>
> > But, this is not my question, sometimes using 'devaluate' breaks
> > completely the code after, it's still compilable but not executable.
> > Any ideas why?
> > R is a Ring.
> > ===== spad ===============
> > NRing :String := string CAR((devaluate(R)$Lisp))$Lisp
> >
> > Rep := SExpression
> > pprint := true
> >
> > getind(m) ==> concat(["getindex(", "refs,_"", jlId m, "_")"])
> > =====
> > And later, the above macro is incorrectly treated (jlId is defined in
> > a category, and call the JLREFID *method*):
> >
> > >> System error:
> > There is no applicable method for the generic function
> > #<STANDARD-GENERIC-FUNCTION BOOT::JLREFID (1)>
> > when called with arguments
> > (|NemoIntegerMod|).
> > See also:
> > The ANSI Standard, Section 7.6.6
> >
> >
> > A work around is:
> > ================================================
> > NRing := CAR((devaluate(R)$Lisp))$Lisp pretend String
> > --NRing :String := string CAR((devaluate(R)$Lisp))$Lisp
>
> Robust use is
>
> op_of_PS : Symbol := CAR(devaluate(PS)$Lisp)$Lisp
>
> Usage like in 'fmtjfricas.spad':
>
> n: String := string CAR(devaluate(f)$Lisp)$Lisp
>
> is error prone: essentially Spad compiler can call _any_ function
> 'string' which returns a String. Namely, '$Lisp' disables normal
> Spad typechecking and Spad compiler belives you that type is
> right one. Without further restictions (like 'string$Symbl')
> Spad will assume that call is OK. But the Lisp expression
> returns Lisp symbol, so return value of Symbol is fine.
> 'pretend String' is wrong, Lisp symbol is _not_ a string.
> Lisp symbol can be treated as SExpression, but 'string' in
> SExpression requires Lisp string so will fail on Lisp symbols.
> One you messed types 'sbcl' is free to generate wrong code.
>
>
> Waldek Hebisch
>
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