On Tuesday, 30 April 2013 at 10:02:07 UTC, JR wrote:
[...]
For instance, is it possible to have MatrixWalker's F type to
have a default value of a NOP void function(), have the
innermost foreach loop check if the element is a function, and
if so call it directly without needing FuncRunner at all?
Let's start by turning MatrixWalker into a function template
(fixing the matrix template parameter on the way):
---
void walkMatrix(F,M: E[I][T],E,I,T)(F func, M matrix) {
/* those foreaches */
}
---
This way it can be called without explicitly instantiating the
template:
---
walkMatrix(&runner, funcyMatrix);
---
Now add an overload for callable elements:
---
void walkMatrix(M: E[I][T],E,I,T)(M matrix)
if(is(typeof(&FuncRunner!M.run))) {
walkMatrix(&FuncRunner!M.run, matrix);
}
---
A call:
---
walkMatrix(funcyMatrix);
---
Of course, FuncRunner is now only needed by that overload, so you
could move its implementation in there.
Also, is there a clever approach to have MatrixWalker call its
passed function variadically with only the arguments that its
signature allows? As in;
-------------
import std.stdio;
import std.concurrency;
struct Event { /* ... type, sender, target, content and
friends ... */ };
template MatrixWalker(F,E: E[I][T],I,T) {
// note addition of Event below
void applyFunc(ref Event evt, F func, E[I][T] matrix) {
/* ... Inception foreach ... */
func(evt, /* only the arguments of E, I and/or T that
type F accepts */);
}
}
const alias Blaawp MAJOR;
const alias Oorgle MINOR;
static void function(ref Event, MINOR)[MINOR][MAJOR]
funcyMatrix;
// note no MAJOR in func sig
void populate() {
/* ... */
}
void traverse() {
sendMessageAdapter = void function(ref Event evt, Tid) {
std.concurrency.send(tid, evt);
};
alias
MatrixWalker!(typeof(&sendMessageAdapter),typeof(funkyMatrix)).applyFunc
apply;
writeln("Traversing funcy matrix");
apply(&sendMessageAdapter, funkyMatrix);
}
void main(string[] args) {
populate();
traverse();
}
-------------
That sounds too good to be true, but it would make me warm and
fuzzy inside if I didn't have to resort to keeping a dozen
adapter/shim functions around.
I don't have a clever solution for that.
