ext::B::B::Lint(3Perl Programmers Reference Guext::B::B::Lint(3p)
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 stan-
dard 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 scalar()
silences the warning. For example,
$foo = scalar(@bar);
implicit-read and implicit-write
These options produce a warning whenever an opera-
tion 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) { ... }
bare-subs
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ext::B::B::Lint(3Perl Programmers Reference Guext::B::B::Lint(3p)
This option warns whenever a bareword is implicitly
quoted, but is also the name of a subroutine in the
current package. Typical mistakes that it will trap
are:
use constant foo => 'bar';
@a = ( foo => 1 );
$b{foo} = 2;
Neither of these will do what a naive user would
expect.
dollar-underscore
This option warns whenever $_ is used either expli-
citly anywhere or as the implicit argument of a
print statement.
private-names
This option warns on each use of any variable, sub-
routine or method name that lives in a non-current
package but begins with an underscore ("_"). Warn-
ings aren't issued for the special case of the sin-
gle 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 vari-
ables $`, $& or $' is used. Any occurrence of any of
these variables in your program can slow your whole
program down. See perlre for details.
all Turn all warnings on.
none Turn all warnings off.
NON LINT-CHECK OPTIONS
-u Package
Normally, Lint only checks the main code of the pro-
gram 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.
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ext::B::B::Lint(3Perl Programmers Reference Guext::B::B::Lint(3p)
This module doesn't work correctly on thread-enabled perls.
Malcolm Beattie, mbeattie@sable.ox.ac.uk.
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