Re: C programs in Scheme syntax

[John Cowan <cowan@ccil.org>]

Check out the Chibi library (chibi show c). in the Chibi repo at
lib/chibi/show/c.scm and .sld.  It provides combinators that create a C
equivalent of the sexp; there is both a macro-based compiler and an
interpreter, IIRC.  Unfortunately there is no real documentation.  There's
some cleverness in it: c-if in statement context expands to an
if-statement, but in an expression context to a ?: operator.  If you import
(chibi show) and (chibi show c) then (show #t (c-if 'foo 'bar 'baz)) will
generate a statement, but (show #t (c+ 2 (c-if 'foo 'bar 'baz))) will
generate an expression.


On Thu, May 28, 2020 at 11:38 PM Keith Wright <kwright@keithdiane.us> wrote:

> I am thinkging about a project that uses Scheme macros
> to generate C code.  To this end I want to encode C
> programs as S-expressions.  For example, the C program
> that is encoded in Ascii as
>
> for (j=0;j<12;++j) a[j] = j*pi/6;
>
> might be encoded as an S-expression as
>
> (for ((= j 0)(< j 12) (++ j)) (= (sub a j)(/ (* j pi) 6)))
>
> Note that this is not a valid Scheme program, even with
> non-standard functions defined.  It is a re-encoding
> of the Ascii C syntax as an S-expression.
>
> I think I have read about something like this, perhaps
> on this list, I am not sure.  (Note to future language
> inventors: a single letter name makes a horrible Google
> search query.  Name things with made up but pronouncable
> words---perl, fortran...)
>
> I most need to convert S-expr encoded C, to Ascii encoded C,
> but I am interested in
> (a) programs to convert S-expresions to C
> (b) specifications for the form of the S-expr encoding
> (c) better plans; advice from those who have tried and failed.
>
> Any pointers?
>
>    -- Keith
>
>
>