Re: scm_num2float() ?

[Michael Livshin]

Martin Baulig <address@hidden> writes:

> Michael Livshin <address@hidden> writes:
> 
> > Martin Baulig <address@hidden> writes:
> > 
> > > what do you think about adding something like
> > > 
> > >     float scm_num2float (SCM a, const char *why);
> > > 
> > > either as function or as macro which does the typechecking
> > > to make sure that the value fits into a C float ?
> > 
> > why would a number _not_ fit in a C float?
> 
> For instance 1.0e40 won't fit into a C float - since MAX_FLT is normally
> about 3.8e38.

ah, right.  sorry.

> I was thinking of something like the following:
> 
> ====
> #define SCM_VALIDATE_FLOAT_COPY(pos,z,cvar) \
>   do { \
>     double x; \
>     SCM_ASSERT (SCM_INUMP (z) || SCM_BIGP (z) || SCM_REALP (z), z, pos, 
> FUNC_NAME); \
>     x = scm_num2dbl (z, FUNC_NAME); \
>     SCM_ASSERT_RANGE (pos, z, (- G_MAXFLOAT <= x) && (x <= G_MAXFLOAT)); \
>     cvar = (float) x; \
>   } while (0)
> ====

I think if we do this, then we should have `scm_num2float' too.

I wonder if I should add this in the stable branch?

-- 
There is no such thing as a "great rock critic" any more than there are
"great parasites".            -- Mike Dickson, in rec.music.progressive