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Re: floating point and other comments
On Saturday 20 December 2003 07:05 pm, Per Bothner wrote:
> I think an "intermediate format" that doesn't support "~8,2F" is
> missing the boat.
Despite the name "intermediate", I consider the srfi-48 level of format to be
basic support in any Scheme runtime. Admittedly, I am biased toward small
runtimes, including embedded implementations--Scheme in a doorknob with led
display or in real-time robotics (e.g. BIT, Scheme48).
For runtime routines I like to see
 no consing--bounded stack use, no heap allocation (if not output to a
 no assignment = no side effects
 a small amount of code which carries its weight
 I will claim without proof that
(display (number->string <num> <radix>) <port>)
can be replaced by a function
(display:number->string <num> <radix> <port>)
which does not allocate heap storage and uses a bounded, calculable stack
 The reference implementation does no assignments
 The complied reference implementation is compact:
mit-scheme format.com 8864 bytes -- bytecode
gambit format.so 16448 bytes -- cross-compiled to C
I have not done the work, but it I would guess that supporting ~w,dF would at
least double the size of the reference implementation. Looking at the ~F
section in the CommonLisp Hyperspec, I likewise suspect that specifying the
complex, rational, rounding, and error conditions would double the size of
Given this amount of effort, I would add ~W for writing circular structures,
~H for help (summary line, comment line, one line of text per option, staring
with the option), and so forth.
I am reluctant to go down this path for (what I see as) such a basic service.
E.g. for use in implementing ERROR.
So the crux of the issue is this. Would acceptance of the current SRFI-48 be
helpful to the community or not? Is there enough benefit for the level of
Alternately, is there enough benefit from ~F (et al) to mandate inclusion for
a small runtime?
My bias is apparent.
What does the Scheme community think?