[erlang-questions] lists:reverse/1 as a built-in function
Sun Jan 14 18:32:26 CET 2007
Thomas Lindgren wrote:
> --- Robert Virding <> wrote:
>>So with this in mind it is not really strange that
>>auto-imported, and have priority over "normal"
>>functions defined in
>>modules; they are part of the language. It is
>>perhaps unfortunate that
>>we allowed definition of functions with the same
>>name and arity as the
> It might have seemed like a good design choice at the
> time, but note that auto-import (with "override") has
> several unfortunate ramifications, which is why it
> should be aged out. As Richard mentioned, one such
> consequence is the difficulty in extending the set of
Sorry I think there is definitely a difference in stature between
functions which are part of the language, BIFs like spawn and link, and
normal user defined functions. If I redefine spawn then I have changed
the semantics of Erlang, just as if I were to allow modifying how
receive or ! works. Just because they have a special syntax does mean
that they are more fundamental than spawn or link. The reason we did not
define a special syntax for them was because they do not need it, and
because what a language does NOT need is a lot of unnecessary extra
syntax. But we can make operators for the lot of them and the problem
will be solved.
> Standardizing the set of functions implemented in C
> doesn't sound like a viable long term solution (nor
> does standardizing the set of overridden functions).
> Disallowing functions with the same names as builtins
> doesn't sound like a very good design choice either.
> Do note that there already is a simple,
> straightforward option that does the right thing.
I never said we should standardise the set of functions implemented in
C, just that we should find a name for functions which are implemented
in C but not part of the language. Using the name BIFs for everything
does not show the difference in stature of the functions. I have no
problems with choice functions from the standard libraries being
implemented in C, it is a question for the development team to decide
which functions are worth the extra effort, but there should definitely
not be a coupling between how functions are implemented and how they are
called. Just because lists:append/2 and lists:reverse/2 (not /1 if I
remember) are implemented in C does not mean you should be able to call
them with just append and reverse.
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