Jonathan Gardner wrote:
One of the bad things with languages like perl and Ruby that call
without parentheses is that getting a function ref is not obvious. You
need even more syntax to do so. In perl:
foo(); # Call 'foo' with no args.
$bar = foo; # Call 'foo; with no args, assign to '$bar'
$bar = &foo; # Don't call 'foo', but assign a pointer to it to '$bar'
# By the way, this '&' is not the bitwise-and '&'!!!!
$bar->() # Call whatever '$bar' is pointing at with no args
Compare with python:
foo() # Call 'foo' with no args.
bar = foo() # 'bar' is now pointing to whatever 'foo()' returned
bar = foo # 'bar' is now pointing to the same thing 'foo' points to
bar() # Call 'bar' with no args
One is simple, consistent, and easy to explain. The other one requires
the introduction of advanced syntax and an entirely new syntax to make
function calls with references.
If you get rid of the syntax specific to Perl, then having to explicitly
obtain a function reference, or to dereference the result, is not such a big
deal:
foo # Call 'foo' with no args.
bar = foo # Call 'foo; with no args, assign to 'bar'
bar = &foo # Don't call 'foo', but assign a pointer to it to 'bar'
bar^ # Call whatever 'bar' is pointing at with no args
(Here I use ^ instead of -> to dereference.) Compared with Python, it saves
3 lots of (), but needs & and ^ added. Still a net saving.
One of the bad things with languages like perl and Ruby that call
without parentheses is that getting a function ref is not obvious.
I'd say that having this "&" symbol in front of "foo" makes it more obvious
than just foo by itself. But I agree not quite as clean.
Another thing is that you have to know whether "bar" is a function, or a
function ref, and use the appropriate syntax. Sometimes this is helpful,
sometimes not.
--
Bartc
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