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=head1 TITLE
Alternate Syntax for variable names
=head1 VERSION
Maintainer: David Corbin <dcorbin@machturtle.com>
Date: 20 Aug 2000
Last Modified: 28 Aug 2000
Version: 2
Mailing List: perl6-language@perl.org
Number: 133
=head1 ABSTRACT
Many new users are confused by the use of $@% to represent context,
when it is also used to declare variables. This is a syntactic change
that introduces a bit more logic to the context/type confusion.
=head1 DESCRIPTION
Context is an essential part of Perl. When evaluating a symbolic
expression, $, @ and % are used to indicate the context of the
expression. However, when variables are declared (using local, my, or
simply implicitly as an lvalue) these same symbols are used. C<my
@array; my %hash; $var=1> To many people, most notably programmers new
to Perl, the $@% is mistakenly believed to be part of the variable
name. This leads to such erroneous attempts to use them as
C<@array[0]>, and C<@%hash{key}>.
Consider the following syntax:
my var; # declaring a scalar
my array[]; # declaring an array
my hash{}; # declaring a hash
Then, when it is necessary to distinguish context explicitly (it often
is not), you can use $@% as before. Consider:
count = array; # scalar context because of assignment to scalar.
alt_array[] = array; # list context
value = hash{key}; #
print $array," ",@array #Context must be clearly designated.
I'm not the linguist that Mr. Wall is, but it strikes me that context
should be derrived automatically as much as possible.
An slightly different alternative would be that arrays and hashes are
always referred to with their trailing indicator ([] or {}). So, from
the example above, you'd have
count=array[];
alt_array[] = array[];
=head1 IMPLEMENTATION
Unknown.
=head1 REFERENCES
RFC 9: Highlander Variable Types
RFC 109: Less linenoise - let's get rid of @%