• d-bugmail puremagic.com (50/55) Apr 13 2014 https://issues.dlang.org/show_bug.cgi?id=12571

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=12571

          Issue ID: 12571
           Summary: Regression (2.063): Can no longer use static
                    introspection on circular references
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: regression
          Priority: P1
         Component: DMD
          Assignee: nobody puremagic.com
          Reporter: andrej.mitrovich gmail.com

This may or may not be a bug. But there was a nice trick from the D Templates
Book[1] which allowed a simple way to extract the symbol name of the current
scope:

-----
mixin template getScopeName()
{
    enum scopeName = __traits(identifier, __traits(parent, scopeName));
}

void main()
{
    mixin getScopeName;
    pragma(msg, scopeName);
}
-----

2.062:
$ dmd test.d
 main

2.063+:
 test.d(3): Error: circular reference to 'test.main.getScopeName!().scopeName'
 test.d(3): Error: argument __error has no parent
 test.d(3): Error: argument false has no identifier
 test.d(8): Error: mixin test.main.getScopeName!() error instantiating

If this is working as expected I suggest we introduce a new trait "scopeName".
I'll file a separate report if this is closed.

I've seen enough people try to hack their way around with using .stringof,
__FUNCTION__, and other tricks just to get the name of the current scope.

There is also a library workaround but it introduces symbol bloat:

-----
mixin template getScopeName()
{
    private enum __unused = 0;
    enum getScopeName = __traits(identifier, __traits(parent, __unused));
}

void main()
{
    mixin getScopeName;
    pragma(msg, getScopeName);  // main
}
-----

[1] : https://github.com/PhilippeSigaud/D-templates-tutorial

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