www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - Restrictred names

reply Sean Kelly <sean f4.ca> writes:
Currently, the double underscore prefix is reserved, but I've been wondering if
there are any other identifier resrictions for D.  C, for example, also reserves
underscore followed by a capital letter for exclusive use, and all other
underscore-prefixed identifiers for use at file scope.  Since it will be quite
common for D to link to C libraries, do these rules hold for D as well?  And
what about the D library itself?  I've noticed that Phobos uses both leading
underscore conventions in different circumstances: the underscore capital
identifiers seem to typically represent C library code, while underscore
lowercase identifiers are more common for D-level externs.  The safest prefix
for D library code is probably some subset of the underscore lowercase range
(such as the "_d_" prefix used for callbacks) but nothing entirely eliminates
the possibility of a conflict.  I think this naming issue is only a concern for
extern(C) functions so there should not be a real risk of collisions anyway, but
I figured it was worth asking.  Should normal folks or library implementors
follow any naming convention?


Sean
Oct 21 2005
parent Sean Kelly <sean f4.ca> writes:
In article <djcbnd$cja$1 digitaldaemon.com>, Sean Kelly says...

Currently, the double underscore prefix is reserved, but I've been wondering if
there are any other identifier resrictions for D.  C, for example, also reserves
underscore followed by a capital letter for exclusive use, and all other
underscore-prefixed identifiers for use at file scope.  Since it will be quite
common for D to link to C libraries, do these rules hold for D as well?  And
what about the D library itself?  I've noticed that Phobos uses both leading
underscore conventions in different circumstances: the underscore capital
identifiers seem to typically represent C library code, while underscore
lowercase identifiers are more common for D-level externs.  The safest prefix
for D library code is probably some subset of the underscore lowercase range
(such as the "_d_" prefix used for callbacks) but nothing entirely eliminates
the possibility of a conflict.  I think this naming issue is only a concern for
extern(C) functions so there should not be a real risk of collisions anyway, but
I figured it was worth asking.  Should normal folks or library implementors
follow any naming convention?


I've considered this a bit and I think the C restrictions must be preserved in
D, simply because D programs can link to C libraries and include imported C
header files.  Since D has visibility specifiers (protected, private), the
file-scope prefix isn't needed by the D library, but a way to use externs is.
Therefore, I propose that the "_D_" subset of the underscore uppercase namespace
be reserved for D library use.  This will allow extern(C) functions to be
declared for library use without any risk of collisions with user or (hopefully)
C library code.  How does this sound?


Sean
Oct 22 2005