"Perl Programmers Reference Guide (англ.) (программ.) /19.12.1998/ " - читать интересную книгу автора

This may seem a bit weird, but that's okay, because it is
weird.

Because variable and array references always start with
'$', '@', or '%', the "reserved" words aren't in fact
reserved with respect to variable names. (They ARE
reserved with respect to labels and filehandles, however,
which don't have an initial special character. You can't
have a filehandle named "log", for instance. Hint: you
could say open(LOG,'logfile') rather than
open(log,'logfile'). Using uppercase filehandles also
improves readability and protects you from conflict with
future reserved words.) Case _I_S significant--"FOO",
"Foo", and "foo" are all different names. Names that
start with a letter or underscore may also contain digits
and underscores.

It is possible to replace such an alphanumeric name with
an expression that returns a reference to an object of
that type. For a description of this, see the _p_e_r_l_r_e_f
manpage.

Names that start with a digit may contain only more
digits. Names that do not start with a letter,
underscore, or digit are limited to one character, e.g.,
$% or $$. (Most of these one character names have a
predefined significance to Perl. For instance, $$ is the
current process id.)

CCCCoooonnnntttteeeexxxxtttt

The interpretation of operations and values in Perl
sometimes depends on the requirements of the context
around the operation or value. There are two major
contexts: scalar and list. Certain operations return list
values in contexts wanting a list, and scalar values
otherwise. (If this is true of an operation it will be
mentioned in the documentation for that operation.) In



14/Jun/98 perl 5.005, patch 02 9





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