[PHP-NOTES] note 130292 added to bcmath-number.construct

It seems that the constructor does not accept values ​​in the scientific format, e.g. "1e20". To get around this limitation, I wrote a function that converts floats represented by a scientific format string to floats represented by a string as a decimal fractional number. You can use the output of this function as the input to the constructor.

<?php
use BCMath\Number;

$num = -123e-40;   // can be a float or string variable, because...
$strNum = sci2dec( $num );  // ...there is an internal float to string conversion
$L = new Number( $strNum );
var_dump( $L );

function sci2dec( string $s ): string
{
	if( !preg_match( '/^([+-]?)(\d+(?:\.\d+)?)[eE]([+-]?\d+)$/', $s, $m ) )
		return $s; // it's not sci format, return unchanged
	[ $sign, $mantissa, $exp ] = [ $m[1], $m[2], (int)$m[3] ];
	[ $int, $frac ] = str_contains( $mantissa, '.' ) ? explode( '.', $mantissa, 2 ) : [ $mantissa, '' ];
	$digits = $int . $frac;
	$exp -= strLen( $frac );
	if( $exp >= 0 )
	{
		$digits .= str_repeat('0', $exp);
		$dec = lTrim($digits, '0');
		return $sign . ( $dec === '' ? '0' : $dec );
	}
	$pos = strLen( $digits ) + $exp;
	if( $pos > 0 ) // kropka w środku
		return $sign . subStr( $digits, 0, $pos ) . '.' . subStr( $digits, $pos );
	return $sign . '0.' . str_repeat( '0', -$pos ) . $digits;
}
?>

Output is:

object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(43) "-0.0000000000000000000000000000000000000123"
  ["scale"]=>
  int(40)
}
----
Server IP: 45.112.84.4
Probable Submitter: 80.90.5.137 (proxied: 193.142.112.99)
----
Manual Page -- https://php.net/manual/en/bcmath-number.construct.php
Edit        -- https://main.php.net/note/edit/130292
Del: integrated  -- https://main.php.net/note/delete/130292/integrated
Del: useless     -- https://main.php.net/note/delete/130292/useless
Del: bad code    -- https://main.php.net/note/delete/130292/bad+code
Del: spam        -- https://main.php.net/note/delete/130292/spam
Del: non-english -- https://main.php.net/note/delete/130292/non-english
Del: in docs     -- https://main.php.net/note/delete/130292/in+docs
Del: other reasons-- https://main.php.net/note/delete/130292
Reject      -- https://main.php.net/note/reject/130292
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