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$xxx <<= 2 don't use "<<=", use the expanded version instead
m@xxx@ don't use m@...@, replace @ with / ! , or |
s:xxx:yyy: don't use s:...:, replace : with / ! , or |
qw/a b c/ don't use qw/.../, use qw(...) instead
qw{a b c} don't use qw{...}, use qw(...) instead
q{xxx} don't use q{...}, use q(...) instead
qq{xxx} don't use qq{...}, use qq(...) instead
qx(xxx) don't use qx(...), use `...` instead
-xxx don't use -xxx, use '-xxx' instead
not $xxx don't use "not", use "!" instead
$1 =~ /xxx/ do not use the result of a match (eg: $1) to match another pattern
$xxx =~ "yyy" use a regexp, not a string
xxx() =~ s/xxx/yyy/ you can only use s/// on a variable
$1 =~ /xxx/ do not use the result of a match (eg: $1) to match another pattern
grep /xxx/, @l always use "grep" with a block (eg: grep { ... } @list)
for (@l) {} write "foreach" instead of "for"
foreach ($xxx = 0; $xxx < 9; $xxx++) {} write "for" instead of "foreach"
foreach $xxx (@l) {} don't use for without "my"ing the iteration variable
foreach ($xxx) {} you are using the special trick to locally set $_ with a value, for this please use "for" instead of "foreach"
unless ($xxx) {} else {} don't use "else" with "unless" (replace "unless" with "if")
unless ($xxx) {} elsif ($yyy) {} don't use "elsif" with "unless" (replace "unless" with "if")
zzz() unless $xxx || $yyy; don't use "unless" when the condition is complex, use "if" instead
$$xxx{yyy} for complex dereferencing, use "->"
wantarray please use wantarray() instead of wantarray
eval please use "eval $_" instead of "eval"
local *F; open F, "foo"; use a scalar instead of a bareword (eg: occurrences of F with $F)
$xxx !~ s/xxx/yyy/ use =~ instead of !~ and negate the return value
pkg::nop $xxx; use parentheses around argument (otherwise it might cause syntax errors if the package is "require"d and not "use"d
new foo $xxx you must parenthesize parameters: "new Class(...)" instead of "new Class ..."
*xxx = *yyy "*xxx = *yyy" is better written "*xxx = \&yyy"
$_xxx = 1 variable $_xxx must not be used
(variable with name _XXX are reserved for unused variables)
sub f2 { my ($x, $_y) = @_; $x } not enough parameters
f2(@l); # ok
f2(xxx()); # bad
$xxx = <<"EOF"; Don't use <<"MARK", use <<MARK instead
foo
EOF
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