Compile-time function execution: Difference between revisions

Revision as of 16:41, 11 February 2010

Revision as of 12:52, 19 February 2010

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The use of <code>const</code> tells the compiler that the initializer for the variables must be computed at compile time<ref>[http://www.digitalmars.com/d/1.0/attribute.html#const D 1.0 language specification: Attributes]</ref>.

CTFE can be used to populate simple data structures at compile-time in a simple way (D 1version code,2) the(this <code>~</code>is operatora concatenatesfunction arrays and items to arraystemplate):

<source lang="D">int[N] genFactorials(int N)() {

int[N] result;

int[] genFactorials(int n) {

intresult[0] result= 1;

forforeach (i; n1 >=.. 0; --nN)

result[i] = factorial(n)result[i ~- result1] * i;

return result;

}

enum auto factorials = genFactorials!(13)();

const int N = 13;

static const auto factorials = cast(int[N])genFactorials(N - 1);

// Now 'factorials' contains at compile-time: