Re: [Chicken-users] How do I name these procedures?

[Thomas Chust]

2010/4/15 Jeronimo Pellegrini <address@hidden>:
> [...]
> Most mpfi functions receive pointer to structures that represent
> intervals, and the return value is the first argument:
>
> mpfi_add (a, b, c);  /* This is a <- b + c */
>
> When translating this into Scheme, I thought I'd offer
> three versions of each function. For example, the function
> mpfi_add, which sums intervals, would generate:
>
> (ia+ia!! a b c) ; same as mpfi (a, b, c)
>
> (ia+ia! a b)    ; defined as (ia+ia!! a a c)
>                ; a will be overwritten
>
> (ia+ia a b)     ; allocates a new structure x and
>                ; does (ia+ia!! x a b)
>                ; See below:
> [...]

Hello Jeronimo,

thinking about it, I would only provide two wrappers per function: One
destructive version that accepts two mandatory input arguments and an
optional output argument defaulting to the first input argument. And
one non-destructive version that accepts just the two input
arguments and allocates an output target.

The code would look like this:

  (define (ia+! a b #!optional [out a])
    ((foreign-lambda void "mpfi_add" c-pointer c-pointer c-pointer)
     out a b)
    out)

  (define (ia+ a b)
    (ia+! a b (make-ia-interval)))

I would also just prefix the operator names with characters, not
suffix them — mostly because of the stylistic similarity to existing
bindings like fx+.

Ciao,
Thomas


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When C++ is your hammer, every problem looks like your thumb.