debian-packages/taggedalgebraic
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Add template constraint to visit/tryVisit.

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This commit is contained in:
Sönke Ludwig 2019-02-22 12:22:38 +01:00
parent 2d9557dc21
commit 1c88c3c65d
1 changed files with 6 additions and 2 deletions
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8
source/taggedalgebraic/taggedunion.d
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@ -339,7 +339,9 @@ unittest { // test for name clashes
....
*/
template visit(VISITORS...) {
template visit(VISITORS...)
if (VISITORS.length > 0)
{
auto visit(TU)(auto ref TU tu)
if (isInstanceOf!(TaggedUnion, TU))
{
@ -422,7 +424,9 @@ private U to(U, T)(T val) {
Instead of failing to compile, `tryVisit` will throw an `Exception` if none
of the handlers is able to handle the value contained in `tu`.
*/
template tryVisit(VISITORS...) {
template tryVisit(VISITORS...)
if (VISITORS.length > 0)
{
auto tryVisit(TU)(auto ref TU tu)
if (isInstanceOf!(TaggedUnion, TU))
{