On 2017-10-24 22:36, H. S. Teoh wrote:
On Tue, Oct 24, 2017 at 01:22:41PM -0600, Jonathan M Davis via Digitalmars-d
wrote:
[...]
Personally, I don't want them in D. If you have enough arguments that
it matters, then the function probably has too many parameters or too
many similar parameters.
If a function has too many parameters, or only a small subset of
parameters need to be something other than some default value, or the
set of parameters may change frequently, then my default approach is to
abstract the parameters into a struct:
struct OutputArgs {
string filename;
int width = 300;
int height = 300;
string fontDir = "/usr/share/local/fonts/arial.ttf";
int fontSize = 12;
Color background = Color.black;
Color foreground = Color.white;
bool antiAlias = true;
}
void generateOutput(OutputArgs args) { ... }
void main() {
// Setup function arguments.
// N.B.: only .filename needs to be explicitly set.
OutputArgs args;
args.filename = "/tmp/output.png";
// Call function with mostly default arguments.
generateOutput(args);
}
For this, it would be nice if static initialization [1] work without
temporary variables. Then it would be pretty close to named parameters.
[1] https://dlang.org/spec/struct.html#static_struct_init
--
/Jacob Carlborg
