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Merge pull request #33 from s-ludwig/issue9_bogus_hasmember_result

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Add stronger restrictions to TA.opDispatch. Fixes #9.
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Sönke Ludwig 2019-10-11 11:19:43 +02:00 committed by GitHub
parent 152e410bdd f8a9b8c651
commit cde25d43bc
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1 changed files with 43 additions and 4 deletions
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47
source/taggedalgebraic/taggedalgebraic.d
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@ -98,10 +98,16 @@ struct TaggedAlgebraic(U) if (is(U == union) || is(U == struct) || is(U == enum)
// combination, so that we can actually decide what to do for each
// case.
/// Enables the invocation of methods of the stored value.
auto ref opDispatch(string name, this TA, ARGS...)(auto ref ARGS args) if (hasOp!(TA, OpKind.method, name, ARGS)) { return implementOp!(OpKind.method, name)(this, args); }
/// Enables accessing properties/fields of the stored value.
@property auto ref opDispatch(string name, this TA, ARGS...)(auto ref ARGS args) if (hasOp!(TA, OpKind.field, name, ARGS) && !hasOp!(TA, OpKind.method, name, ARGS)) { return implementOp!(OpKind.field, name)(this, args); }
/// Enables the access to methods and propeties/fields of the stored value.
template opDispatch(string name)
if (hasAnyMember!(TaggedAlgebraic, name))
{
/// Enables the invocation of methods of the stored value.
auto ref opDispatch(this TA, ARGS...)(auto ref ARGS args) if (hasOp!(TA, OpKind.method, name, ARGS)) { return implementOp!(OpKind.method, name)(this, args); }
/// Enables accessing properties/fields of the stored value.
@property auto ref opDispatch(this TA, ARGS...)(auto ref ARGS args) if (hasOp!(TA, OpKind.field, name, ARGS) && !hasOp!(TA, OpKind.method, name, ARGS)) { return implementOp!(OpKind.field, name)(this, args); }
}
/// Enables equality comparison with the stored value.
auto ref opEquals(T, this TA)(auto ref T other)
if (is(Unqual!T == TaggedAlgebraic) || hasOp!(TA, OpKind.binary, "==", T))
@ -764,6 +770,38 @@ private struct DisableOpAttribute {
string name;
}
private template hasAnyMember(TA, string name)
{
import std.traits : isAggregateType;
alias Types = TA.UnionType.FieldTypes;
template impl(size_t i) {
static if (i >= Types.length) enum impl = false;
else static if (!isAggregateType!(Types[i])) enum impl = impl!(i+1);
else static if (__traits(hasMember, Types[i], name))
enum impl = true;
else enum impl = impl!(i+1);
}
alias hasAnyMember = impl!0;
}
unittest {
import std.range.primitives : isOutputRange;
import std.typecons : Rebindable;
struct S { int a, b; void foo() {}}
interface I { void bar() immutable; }
static union U { int x; S s; Rebindable!(const(I)) i; }
alias TA = TaggedAlgebraic!U;
static assert(hasAnyMember!(TA, "a"));
static assert(hasAnyMember!(TA, "b"));
static assert(hasAnyMember!(TA, "foo"));
static assert(hasAnyMember!(TA, "bar"));
static assert(!hasAnyMember!(TA, "put"));
static assert(!isOutputRange!(TA, int));
}
private template hasOp(TA, OpKind kind, string name, ARGS...)
{
@ -796,6 +834,7 @@ unittest {
static assert(!hasOp!(TA, OpKind.method, "m"));
static assert(!hasOp!(const(TA), OpKind.binary, "+=", int));
static assert(!hasOp!(const(TA), OpKind.method, "m", int));
static assert(!hasOp!(TA, OpKind.method, "put", int));
}
unittest {