NAME¶
Perl::Critic::Policy::NamingConventions::Capitalization - Distinguish different
program components by case.
AFFILIATION¶
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION¶
Conway recommends to distinguish different program components by case.
Normal subroutines, methods and variables are all in lower case.
my $foo; # ok
my $foo_bar; # ok
sub foo {} # ok
sub foo_bar {} # ok
my $Foo; # not ok
my $foo_Bar; # not ok
sub Foo {} # not ok
sub foo_Bar {} # not ok
Package and class names are capitalized.
package IO::Thing; # ok
package Web::FooBar # ok
package foo; # not ok
package foo::Bar; # not ok
Constants are in all-caps.
Readonly::Scalar my $FOO = 42; # ok
Readonly::Scalar my $foo = 42; # not ok
There are other opinions on the specifics, for example, in perlstyle. This
policy can be configured to match almost any style that you can think of.
CONFIGURATION¶
You can specify capitalization rules for the following things:
"packages", "subroutines",
"local_lexical_variables", "scoped_lexical_variables",
"file_lexical_variables", "global_variables",
"constants", and "labels".
"constants" are things declared via constant or Readonly.
use constant FOO => 193;
Readonly::Array my @BAR => qw< a b c >;
"global_variables" are anything declared using "local",
"our", or vars. "file_lexical_variables" are variables
declared at the file scope.
"scoped_lexical_variables" are variables declared inside bare blocks
that are outside of any subroutines or other control structures; these are
usually created to limit scope of variables to a given subset of subroutines.
E.g.
sub foo { ... }
{
my $thingy;
sub bar { ... $thingy ... }
sub baz { ... $thingy ... }
}
All other variable declarations are considered
"local_lexical_variables".
Each of the "packages", "subroutines",
"local_lexical_variables", "scoped_lexical_variables",
"file_lexical_variables", "global_variables",
"constants", and "labels" options can be specified as one
of ":single_case", ":all_lower", ":all_upper:",
":starts_with_lower", ":starts_with_upper", or
":no_restriction" or a regular expression; any value that does not
start with a colon, ":", is considered to be a regular expression.
The ":single_case" tag means a name can be all lower case or all
upper case. If a regular expression is specified, it is surrounded by
"\A" and "\z".
"packages" defaults to ":starts_with_upper".
"subroutines", "local_lexical_variables",
"scoped_lexical_variables", "file_lexical_variables", and
"global_variables" default to ":single_case". And
"constants" and "labels" default to
":all_upper".
There are corresponding "package_exemptions",
"subroutine_exemptions",
"local_lexical_variable_exemptions",
"scoped_lexical_variable_exemptions",
"file_lexical_variable_exemptions",
"global_variable_exemptions", "constant_exemptions", and
"label_exemptions" options that are lists of regular expressions to
exempt from the corresponding capitalization rule. These values also end up
being surrounded by "\A" and "\z".
"package_exemptions" defaults to "main".
"global_variable_exemptions" defaults to "\$VERSION @ISA
@EXPORT(?:_OK)? %EXPORT_TAGS \$AUTOLOAD %ENV %SIG \$TODO".
"subroutine_exemptions" defaults to "AUTOLOAD BUILD BUILDARGS
CLEAR CLOSE DELETE DEMOLISH DESTROY EXISTS EXTEND FETCH FETCHSIZE FIRSTKEY
GETC NEXTKEY POP PRINT PRINTF PUSH READ READLINE SCALAR SHIFT SPLICE STORE
STORESIZE TIEARRAY TIEHANDLE TIEHASH TIESCALAR UNSHIFT UNTIE WRITE" which
should cover all the standard Perl subroutines plus those from Moose.
For example, if you want all local variables to be in all lower-case and global
variables to start with "G_" and otherwise not contain underscores,
but exempt any variable with a name that contains "THINGY", you
could put the following in your
.perlcriticrc:
[NamingConventions::Capitalization]
local_lexical_variables = :all_lower
global_variables = G_(?:(?!_)\w)+
global_variable_exemptions = .*THINGY.*
TODO¶
Handle "use vars". Treat constant subroutines like constant variables.
Handle bareword file handles. There needs to be "schemes" or ways of
specifying "perlstyle" or "pbp". Differentiate lexical
Readonly constants in scopes.
BUGS¶
This policy won't catch problems with the declaration of $y below:
for (my $x = 3, my $y = 5; $x < 57; $x += 3) {
...
}
AUTHOR¶
Multiple people
COPYRIGHT¶
Copyright (c) 2008-2011 Michael G Schwern. All rights reserved.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself. The full text of this license can be found in
the LICENSE file included with this module.