Xah Lee wrote:
In many languages, they don't have namespace and is often a well known
sour point for the lang. For example, Scheme has this problem up till
R6RS last year. PHP didn't have namespace for the past decade till
about this year. Javascript, which i only have working expertise,
didn't have namespace as he mentioned in his blog. Elisp doesn't have
name space and it is a well known major issue.
Namespaces are useful for one reason: they allow you to have conflicts
with names in some cases. In Java, there are two Lists: java.awt.List
and java.util.List. Since a name must only be unique within a namespace,
you can use shorter names without fear of conflict.
In languages without these namespaces, you end up with stuff like
g_type_init, e_data_server_module_init, mysql_connect, etc., where the
prefixes are used to emulate the unique nature of namespaces.
Of languages that do have namespace that i have at least working
expertise: Mathematica, Perl, Python, Java. Knowing these langs
sufficiently well, i do not see anything special about namespace.
Most features aren't sufficiently appreciated until one has to do
without it. The avoidance of collision that comes with namespaces has
shown to be sufficiently useful that I doubt we'll ever see a future
major language that doesn't have some sort of namespace feature.
> The
_essence_ of namespace is that a char is choosen as a separator, and
the compiler just use this char to split/connect identifiers.
That's just composition of namespace names. It's not what namespaces is
about.
i cannot fathom what could possibly be difficult of
introducing or implementing a namespace mechanism into a language.
Namespaces go to the very core of a language, name resolution.
Retroactively adding such a feature is extremely difficult because there
is a strong chance of accidentally breaking existing code.
> I
do not understand, why so many languages that lacks so much needed
namespace for so long? If it is a social problem, i don't imagine they
would last so long. It must be some technical issue?
It's technical: it would be difficult to retroactively implement such a
feature.
--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth
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