NAME
Perl::Critic::Policy::ValuesAndExpressions::ProhibitLiteralArithmetic - Write a number as the number it is, not as arithmetic on other numbers.
VERSION
version 0.001
Perl::Critic::Policy::ValuesAndExpressions::ProhibitLiteralArithmetic
Arithmetic whose operands are all literal numbers computes, every time it runs, a value that never changes. The reader then has to do the arithmetic to learn what the value is. Write the value, with digit separators where they help:
my $GB = 1024 * 1024 * 1024; # reported
my $GB = 1024 ** 3; # reported
my $GB = 1_073_741_824; # what to writePROHIBITED
my $day = 60 * 60 * 24;
my $mask = 1 << 20;
use constant TIMEOUT => 5 * 60;
my $x = $y + 2 * 3; # 2 * 3 is computed before the +
my $x = 2 * 3 + $y; # and so is this one
my $x = $y ** 2 ** 3; # ** is right associative: 2 ** 3 firstALLOWED
my $x = $y * 2 + 3; # $y * 2 first, then + 3
my $x = $y - 2 - 3; # ($y - 2) - 3
my $x = 2 ** 3 ** $y; # 2 ** (3 ** $y)
my @r = 1 .. 10; # a range, not arithmetic
my $s = '-' x 72; # repetition, not arithmetic
my $n = -1; # a negative literal
my $v = 1024 * $size; # a variable is not a literalWHAT COUNTS
An expression is reported when an operator in it has a literal number on each side, after perl's precedence and associativity decide what each side is. The operators are **, *, /, %, +, -, << and >>. A literal is a number in any notation that PPI reads as one, decimal, hex, octal, binary or exponent, with or without its sign. A version string such as v5.14 is not a number here.
One expression is one violation, at its first number, however many operators it has.
CAVEATS
PPI gives a statement as a list of tokens, not as a tree. So the policy applies perl's precedence to that list itself, and it knows the binary operators of perlop that can sit beside a number. An operator it does not know is taken to bind more loosely than any of these, which is true of every one that is left: the comparisons, the logical operators, the ternary, assignment and the comma.
Parentheses are a structure of their own in PPI. (2 + 3) * 4 is reported at 2 + 3, inside them, and not as the whole expression. Whoever writes out that value writes out the whole of it anyway.
METHODS
supported_parameters
default_severity
default_themes
applies_to
violates
BUGS
Please report any bugs or feature requests on the bugtracker website https://github.com/teodesian/perl-critic-policy-prohibitliteralarithmetic/issues
When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.
AUTHORS
Current Maintainers:
George S. Baugh <george@troglodyne.net>
COPYRIGHT AND LICENSE
Copyright (c) 2026 Troglodyne LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.