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@{$xxx} @{$xxx} can be written @$xxx
$h{"yyy"} {"yyy"} can be written {yyy}
"$xxx" $xxx is better written without the double quotes
$xxx->{yyy}->{zzz} the arrow "->" is unneeded
"xxx\$xxx" you can replace "xxx\$xxx" with 'xxx$xxx', that way you don't need to escape <$>
"xxx\$xxx" you can replace "xxx\$xxx" with 'xxx$xxx', that way you don't need to escape <$>
"xxx\"$xxx" you can replace "xxx\"xxx" with qq(xxx"xxx), that way you don't need to escape <">
/xxx\'xxx/ you can replace \' with '
/xxx\;xxx/ you can replace \; with ;
/\// change the delimit character / to get rid of this escape
{ nop(); } spurious ";" before closing block
+1 don't use unary +
return ($xxx) unneeded parentheses
if (($xxx eq $yyy) || $zzz) {} unneeded parentheses
if (($xxx =~ /yyy/) || $zzz) {} unneeded parentheses
nop() foreach ($xxx, $yyy); unneeded parentheses
($xxx) ||= 'xxx' remove the parentheses
$o->m0() remove these unneeded parentheses
$o = xxx() if !$o; "$foo = ... if !$foo" can be written "$foo ||= ..."
$o = xxx() unless $o; "$foo = ... unless $foo" can be written "$foo ||= ..."
$o or $o = xxx(); "$foo or $foo = ..." can be written "$foo ||= ..."
$_ =~ s/xxx/yyy/ "$_ =~ s/regexp/.../" can be written "s/regexp/.../"
$xxx =~ /^yyy$/ "... =~ /^yyy$/" is better written "... eq 'yyy'"
/xxx.*/ you can remove ".*" at the end of your regexp
/xxx.*$/ you can remove ".*$" at the end of your regexp
/[^\s]/ you can replace [^\s] with \S
/[^\w]/ you can replace [^\w] with \W
$xxx ? $xxx : $yyy you can replace "$foo ? $foo : $bar" with "$foo || $bar"
my @l = (); no need to initialize variables, it's done by default
$l[$#l] you can replace $#l with -1
$#l == 0 $#x == 0 is better written @x == 1
$#l == -1 $#x == -1 is better written @x == 0
$#l < 0 change your expression to use @xxx instead of $#xxx
$l[@l] = 1 "$a[@a] = ..." is better written "push @a, ..."
xxx(@_) replace xxx(@_) with &xxx
member($xxx, keys %h) you can replace "member($xxx, keys %yyy)" with "exists $yyy{$xxx}"
!($xxx =~ /.../) !($var =~ /.../) is better written $var !~ /.../
!($xxx == 1) !($foo == $bar) is better written $foo != $bar
!($xxx eq 'foo') !($foo eq $bar) is better written $foo ne $bar
grep { !member($_, qw(a b c)) } @l you can replace "grep { !member($_, ...) } @l" with "difference2([ @l ], [ ... ])"
any { $_ eq 'foo' } @l you can replace "any { $_ eq ... } @l" with "member(..., @l)"
foreach (@l) { use "push @l2, grep { ... } ..." instead of "foreach (...) { push @l2, $_ if ... }"
push @l2, $_ if yyy($_); or sometimes "@l2 = grep { ... } ..."
}
foreach (@l) { use "push @l2, map { ... } ..." instead of "foreach (...) { push @l2, ... }"
push @l2, yyy($_); or sometimes "@l2 = map { ... } ..."
}
foreach (@l) { use "push @l2, map { ... ? ... : () } ..." instead of "foreach (...) { push @l2, ... if ... }"
push @l2, yyy($_) if zzz($_); or sometimes "@l2 = map { ... ? ... : () } ..."
} or sometimes "@l2 = map { if_(..., ...) } ..."
if (grep { xxx() } @l) {} in boolean context, use "any" instead of "grep"
$xxx = grep { xxx() } @l; you may use "find" instead of "grep"
$xxx ? $yyy : () you may use if_() here
beware that the short-circuit semantic of ?: is not kept
if you want to keep the short-circuit behaviour, replace () with @{[]} and there will be no warning anymore
system(qq(foo "$xxx")) instead of quoting parameters you should give a list of arguments
system("mkdir", $xxx) you can replace system("mkdir ...") with mkdir(...)
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