isCallable is not an expression

[andre via Digitalmars-d-learn]

Hi,
following code throws an error when I uncomment method 
getPropertyDuplicate.
getPropertyDuplicate is just a copy of getProperty except the 
method name.


Why these errors are thrown?

C:\D\dmd2\windows\bin\..\..\src\phobos\std\traits.d(1257): Error: 
isCallable!(ge

tPropertyDuplicate) is not an expression
source\app.d(25):while looking for match for 
functionAttributes!(getProp

ertyDuplicate)
C:\D\dmd2\windows\bin\..\..\src\phobos\std\traits.d(1257): Error: 
template insta
nce std.traits.isCallable!(getPropertyDuplicate) error 
instantiating
source\app.d(11):instantiated from here: 
functionAttributes!(getProperty

Duplicate)
source\app.d(11):while looking for match for 
functionAttributes!(getProp

ertyDuplicate)

Kind regards
André

template MyTemplate()
{
	import std.traits : isSomeFunction, functionAttributes, 
FunctionAttribute, ReturnType;


string[] getPropertyNames()
{
string[] result;
foreach(m;__traits(allMembers, typeof(this)))
{
			static if (isSomeFunction!(__traits(getMember, typeof(this), 
m))
			  && functionAttributes!(__traits(getMember, typeof(this), m)) 
& FunctionAttribute.property)

{
result ~= m;
}
}
return result;
}

/*string[] getPropertyDuplicate()
{
string[] result;
foreach(m;__traits(allMembers, typeof(this)))
{
			static if (isSomeFunction!(__traits(getMember, typeof(this), 
m))
			  && functionAttributes!(__traits(getMember, typeof(this), m)) 
& FunctionAttribute.property)

{
result ~= m;
}
}
return result;
}*/
}

class A {
mixin MyTemplate;
}

void main() {
auto a = new A();
}

Re: isCallable is not an expression

[Ali Çehreli via Digitalmars-d-learn]

On 09/24/2014 01:11 AM, andre wrote:


 static if (isSomeFunction!(__traits(getMember,
typeof(this), m))


Submitted the following bug report:

  https://issues.dlang.org/show_bug.cgi?id=13528

import std.traits;

mixin template MyTemplate()
{
void foo()
{
pragma(msg, __traits(getMember, typeof(this), "foo"));
}
}

class A
{
mixin MyTemplate;
}

void main()
{
auto a = new A();
}

Error: Internal Compiler Error: CTFE DotType: this.A
   while evaluating pragma(msg, __traits(getMember, A, "foo"))

Ali

Re: isCallable is not an expression

[Ali Çehreli via Digitalmars-d-learn]

On 09/24/2014 01:11 AM, andre wrote:

> template MyTemplate()
> {
>  import std.traits : isSomeFunction, functionAttributes,
> FunctionAttribute, ReturnType;
>
>  string[] getPropertyNames()

1) You need a "this template parameter":

string[] getPropertyNames(this MyType)()

2) Now, replace all typeof(this) expressions with MyType below.

>  /*string[] getPropertyDuplicate()

3) Same here:

string[] getPropertyDuplicate(this MyType)()

And it works! :)

class A {
mixin MyTemplate;
@property int zzz()
{
return 42;
}
}

void main() {
auto a = new A();

import std.string;
assert(a.getPropertyNames() == [ "zzz" ]);
assert(a.getPropertyDuplicate() == [ "zzz" ]);
}

Ali

Re: isCallable is not an expression

[andre via Digitalmars-d-learn]

Thanks a lot.

Kind regards
André