=head1 TITLE

length(@ary) deserves a warning

=head1 VERSION

  Maintainer: Nathan Torkington <gnat@frii.com>
  Date: 15 Sep 2000
  Mailing List: perl6-language-subs@perl.org
  Number: 238
  Version: 1
  Status: Developing
  Supercedes: RFC 212

=head1 ABSTRACT

Beginners often try C<length(@ary)> (which has bizarre consequences and 
no real purpose).  Make it emit a warning.

=head1 DESCRIPTION

Beginners think of the size of an array as its length, so try to use 
the length() function to find this information.  They should be told 
by the compiler that this is not correct.

The warning would be triggered when Perl finds an array in scalar 
context as the argument to length().  The construct serves no useful 
purpose otherwise, so backwards compatibility isn't a problem.

While I originally suggested "just make it work", this would (1) steer 
users away from the real understanding of context; (2) require changes 
to the prototype system to permit length() to still be overridable.  
While it is a good idea to do what users want, in this case I've been 
convinced that the user would benefit from being told the correct way 
to do it.

=head1 IMPLEMENTATION

When you check a length() function call, warn if its argument is a
scalar-context array.

=head1 REFERENCES

RFC 212: (retired) Make length(@array) work

perlfunc manpage for information on the length() function