Hello Johannes,

W dniu 01.09.2016 o 15:56, Johannes Schindelin pisze: 
> On Thu, 1 Sep 2016, Jakub Narębski wrote:

>> It's a pity that emulation of named parameters in C requires
>> relying on designated inits from C99
>>   typedef struct {
>>     double pressure, moles, temp;
>>   } ideal_struct;
>>   #define ideal_pressure(...) 
>> ideal_pressure_base((ideal_struct){.pressure=1,   \
>>                                         .moles=1, .temp=273.15, __VA_ARGS__})
>>   double ideal_pressure_base(ideal_struct in)
>>   {
>>     return 8.314 * in.moles*in.temp/in.pressure;
>>   }
>>   ... ideal_pressure(.moles=2, .temp=373.15) ...

Forgot to add citation:

[1] Ben Klemens "21st Century C: C Tips from the New School", 2nd Ed. (2014),
    O'Reilly Media, chapter 10. "Better Structures", subsection
    "Optional and Named Arguments"

> Yeah, that looks unwieldy ;-)

Declaration needs some trickery, but use is much, much more readable
(if we cannot use sensibly named variables for passing arguments):

  ideal_pressure(.moles=2, .temp=373.15) 

It is even better if there are large amount of parameters:

  res = amortization(.amount=200000, .inflation=3,
                     .show_table=0, .extra_payoff=100)


  double amortize(double amt, double rate, double inflation, int months,
            int selloff_month, double extra_payoff, int verbose,
            double *interest_pv, double *duration, double *monthly_payment);

But we can't use it in Git, anyway
Jakub Narębski

Reply via email to