B::Lint - Perl lint
perl -MO=Lint[,OPTIONS] foo.pl
The B::Lint module is equivalent to an extended version of the -w
option of perl. It is named after the program lint which carries out a similar process for
C programs.
Option words are separated by commas (not whitespace) and follow the usual
conventions of compiler backend options. Following any options (indicated
by a leading -) come lint check arguments. Each such argument (apart from the special all and none options) is a word representing one possible lint check (turning on that
check) or is no-foo (turning off that check). Before processing the check arguments, a standard
list of checks is turned on. Later options override earlier ones. Available
options are:
- context
-
Produces a warning whenever an array is used in an implicit scalar context.
For example, both of the lines
$foo = length(@bar);
$foo = @bar;
will elicit a warning. Using an explicit B<scalar()> silences the
warning. For example,
$foo = scalar(@bar);
- implicit-read and implicit-write
-
These options produce a warning whenever an operation implicitly reads or
(respectively) writes to one of Perl's special variables. For example, implicit-read will warn about these:
/foo/;
and implicit-write will warn about these:
s/foo/bar/;
Both implicit-read and implicit-write warn about this:
for (@a) { ... }
- dollar-underscore
-
This option warns whenever
$_ is used either explicitly
anywhere or as the implicit argument of a print statement.
- private-names
-
This option warns on each use of any variable, subroutine or method name
that lives in a non-current package but begins with an underscore (``_'').
Warnings aren't issued for the special case of the single character name
``_'' by itself (e.g.
$_ and @_).
- undefined-subs
-
This option warns whenever an undefined subroutine is invoked. This option
will only catch explicitly invoked subroutines such as
foo() and not indirect invocations such as &$subref()
or $obj->meth(). Note that some programs or modules delay definition of subs until runtime by means of the
AUTOLOAD mechanism.
- regexp-variables
-
This option warns whenever one of the regexp variables $', $& or $' is
used. Any occurrence of any of these variables in your program can slow
your whole program down. See the perlre manpage for details.
- all
-
Turn all warnings on.
- none
-
Turn all warnings off.
- -u Package
-
Normally, Lint only checks the main code of the program together with all
subs defined in package main. The -u option lets you include other package names whose subs are then checked by
Lint.
This is only a very preliminary version.
Malcolm Beattie, mbeattie@sable.ox.ac.uk.
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