/ 
Math-JS-0.03
River stage zero No dependents
/ Math::JS

NAME

Math::JS - Emulate JavaScript arithmetic in perl

DESCRIPTION

Assign numeric values to Math::JS objects, and perform arithmetic
operations on those values according to the rules that JavaScript
uses.
This module was prompted by https://www.perlmonks.org/?node=11155911
and the unexpected arithmetical behaviour revealed therein.
JavaScript uses the C 'double' as its floating point data type, and
therefore the building of Math::JS is restricted to perls that have
that same configuration - ie where $Config{nvtype} is 'double' and
$Config{nvsize} is 8.
Prior to perl-5.30, perl's assignment of floating-point values to
double-precision NVs was buggy - hence we also limit this module to
perl-5.30.0 and later.

SYNOPSIS

use warnings; use strict;
use Math::JS;

my $js0 = Math::JS->new(2147483648);
$js0 >>= 1;
print $js0, "\n";
# Outputs -1073741824 (same as JavaScript)
my $js1 = ($js0 + 10000) & 123456789;
print $js1, "\n";
# Outputs 1296  (same as javascript)

FUNCTIONS

Exports no functions by default, and only one finction upon request:

$rop = urs($op, $shift);
  Emulate JavaScript's '>>>' operator.
  An usnsigned 32-bit rightshift of $shift places is performed on the
  value held by the Math::JS object $op. $rop is a created Math::JS
  object that holds, as its value, the result of that right shift.

Overloading of the '+', '-', '*', '/', '%', '**', '++', '--', '>=',
'<=', '==', '!=', '>', '<', '<=>', '""', '+=', '-=', '*=', '/=', '%=',
'**=', '&', '|', '^', '~', '&=',  '|=', '^=' operators is provided.

DISPLAYING FLOATING POINT VALUES

This warrants some specific documentation because it's not trivial to
get Perl to print out the values in the same form as JavaScript does.
(That's in addition to the fact that perl's print() function likes to
present inaccurate values, whereas JavaScript does not.)

The overloading of '""' uses perl's sprintf() function, which might present
more decimal mantissa digits than JavaScript does - though both forms will
accurately represent exactly the same double-precision value.

TODO: Use Math::Ryu to format the string, instead of perl's sprintf().
      But first, I have to reformat the string that Math::Ryu returns,
      otherwise little will have been achieved.

LICENSE

This program is free software; you may redistribute it and/or
modify it under the same terms as Perl itself.
Copyright 2024, Sisyphus

AUTHOR

Sisyphus <sisyphus at(@) cpan dot (.) org>